Altered salivary mucin composition in head and neck cancer patients prior to radiotherapy and its clinical implications for oral health

Altered salivary mucin composition in head and neck cancer patients prior to radiotherapy and its clinical implications for oral health | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Altered salivary mucin composition in head and neck cancer patients prior to radiotherapy and its clinical implications for oral health Maria G Agurto, Gabriel Andrade Cabrera, Sophie S Bozorgi, nicolas olivares, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9558012/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Objectives to examine pre-treatment salivary protein composition and secretion rate of head and neck cancer (HNC) patients and their association with oral health status, specifically clinical caries lesions. Material and Methods A cross-sectional study was conducted, including 40 HNC patients before undergoing intensity-modulated radiotherapy (IMRT) and 28 age- and sex-matched non-cancer controls. (Ethical approval/consent). Unstimulated whole-mouth saliva was collected under standardised conditions. Salivary flow rate, total protein concentration, and secretion rate were assessed. Specific proteins were evaluated(MUC5B, MUC7, ALBUMIN, cystatin S and α-amylase). The dental status was obtained clinically. Differences between groups were analysed using a nonparametric test, and regression models assessed the associations between salivary parameters, cancer status, and the presence of caries. Results There was a significant reduction in MUC5B (p < 0.0001) and MUC7 (p < 0.0001) concentrations and secretion rates (p = 0.0004 and p < 0.0001, respectively) in HNC patients. Despite no significant differences in flow rate and total protein secretion rate, albumin concentration (p = 0.009) and secretion rate (p = 0.02) significantly increased. Clinically, HNC patients had poorer dental status, with fewer healthy teeth and a higher prevalence of carious lesions. In the HNC group, lower MUC7 concentration was associated with the presence of caries lesions. Regression models confirmed that the reduction in mucins was independently associated with cancer status after adjusting for smoking. Conclusion HNC patients exhibit significant alterations in protein composition before IMRT, particularly affecting mucin secretion, while overall gland function remained preserved. These outcomes suggest that salivary dysfunction prior to IMRT may increase susceptibility to oral disease, particularly carious lesions. Clinical relevance: pre-radiotherapy assessment of salivary composition may help to identify HNC patients at increased risk of late oral complications and support the development of tailored preventive strategies before the cancer treatment. Head and Neck cancer Saliva Salivary Proteins Mucins caries radiotherapy Figures Figure 1 Figure 2 1. Introduction Head and neck cancers (HNCs) are the sixth most common malignancy globally, accounting for approximately 4–5% of all cases [ 1 – 5 ] . Oral squamous cell carcinoma (OSCC) accounts for 80 to 90% of head and neck cancers [ 6 ] . Despite advances in diagnosis and treatment, many cases are often diagnosed at later stages, leading to significant morbidity (Cancer Research UK, 2023; Pfister et al., 2020). Radiotherapy, particularly intensity-modulated radiation therapy (IMRT), plays a fundamental role in HNC treatment; however, it is associated with debilitating oral side effects, comprising salivary gland dysfunction, xerostomia, radiotherapy-induced caries, and osteoradionecrosis, all of which impair quality of life [ 2 , 8 – 15 ] . Salivary proteins are vital for dental health through lubrication, pellicle formation, antimicrobial activity, and mineral homeostasis. These functions influence bacterial colonisation and the development of carious lesions [ 16 ] . Previous studies have demonstrated an association between total salivary protein concentration and radiation-induced caries (RC) [ 10 ] ; however, the specific pre-treatment salivary protein profile associated with caries risk in HNC remains unclear. This is important due to the poor oral health status among HNC patients prior to treatment initiation [ 17 ] . Among salivary glycoproteins, MUC5B and MUC7 contribute to lubrication and microbial regulation, serving as the first line of defence in the mouth [ 18 – 25 ] . Altered mucin concentration or function may disrupt oral homeostasis and promote microbial dysbiosis [ 19 , 26 , 27 ] , increasing caries risk [ 28 , 29 ] . Other salivary proteins are also associated with caries risk. α-amylase, contributes to microbial metabolism [ 29 ] , biofilm formation and bacterial adhesion [ 18 , 28 – 32 ] . Albumin reflects gland epithelial permeability and inflammation [ 18 , 33 ] . Cystatin S plays a role in remineralisation [ 34 , 35 ] and in antibacterial defence. Cystatin S level has been associated with caries risk [ 34 , 36 ] . However, their role in HNC patient’s pre-treatment remains unclear. To date, no studies have comprehensively characterised the pre-treatment salivary protein profile in HNC patients in association with caries lesions Aim This cross-sectional study aimed to compare salivary protein composition and secretion rates between HNC patients before IMRT and in age- and sex-matched non-cancer controls and to assess their association with caries lesions. 2. Materials and Methods Study design A Cross-sectional study of HNC patients was conducted over 12 months at Guy’s and St Thomas’ Hospital National Health Service (NHS) Foundation Trust, London, UK. HNC patients were assessed before the initiation of IMRT and compared with age and sex matched controls, non-cancer controls. Outcomes measured : To evaluate the differences in caries lesion presence of head and neck cancer patients pre-IMRT with age and sex matched controls, non-cancer controls. To assess salivary flow rate, protein composition and secretion rates between HNC patients before IMRT and in age- and sex-matched non-cancer controls and the possible associations with caries lesions Ethics approval The North Scotland Research Ethics Service Committee approved the study (16/NS/0116, IRAS Project ID: 199,100). All participants provided written informed consent. Adverse events were reported in accordance with UK guidelines. However, no adverse events or safety concerns were reported during the study. Data of the Study . This study was submitted to the Research Data Protection Registration at King’s College London Research Governance (KDPR). Registration Reference: DPRF-17/18-6377. Patient enrolment We consecutively enrolled forty dentate adults with HNC before starting IMRT, and 28 non-cancer control subjects at Guys and Thomas Foundation Trust (London, UK) over 12 months (February 2017 – February 2018). Non-cancer controls were frequency matched to HNC cases by sex (male/female) and age (55–70 years) at the group level. This resulted in a final number of 28 non-cancer subjects due to clinic workflow and eligibility criteria. Analysis used independent group methods for the final sample, with age and sex included where applicable. Inclusion criteria Patients aged 18 years or older, dentate (with at least one tooth) and with a permanent dentition were eligible. Confirmed HNC with no distant metastases, evaluated pre-IMRT. For the non-cancer control group, there was no history of head and neck cancer or radiotherapy/chemotherapy. Stable systemic diseases controlled by regular medication were included. Additionally, smoking and drinking habits were analysed in subjects. Exclusion criteria Patients with Sjogren’s syndrome or other disorders that affect salivary flow rate, uncontrolled diabetes mellitus, uncontrolled hypertension, and those who have used antibiotics within the last three months. Patients receiving parenteral nutrition. Sample collection and biochemical analysis Saliva collection/assessment Unstimulated Whole Mouth Saliva (UWMS) was collected by the passive drooling method for 10 minutes after a minimum of 60 minutes of fasting. Collection was performed regularly between 13:30 and 15:30 to minimise the potential effects of circadian variation. Samples were transported on ice to the laboratory, aliquoted, and centrifuged at 10,000 g for 5 minutes at 4°C. The aliquots were then stored at − 80°C. The Salivary flow rate (SFR) was calculated (volume per minute, mL/min). Salivary Biochemical assays Total protein concentration (TPC) analysis. Total protein concentration was assessed using a bicinchoninic acid assay (BCA) kit (Pierce, Rockford, IL, USA). Samples were evaluated in duplicate. Total protein secretion rate (TPS) analysis This was calculated by multiplying the salivary flow rate (mL/min) by the protein concentration (µg/mL), yielding the rate in µg/min. Furthermore, the secretion rate of each protein was calculated to quantify the amount delivered to the oral cavity. Selected proteins analysis MUC5B and 7 analyses. After determining the total protein concentration, mucins 5B and 7 were analysed by SDS-PAGE. 20 µg of salivary proteins were loaded onto NuPAGE Novex 4%–12% bis-tris gels under reducing conditions and heated to separate the proteins by molecular weight. Mucins 5B and 7 were stained with polysaccharide periodic acid–Schiff reagent to identify mucin glycosylation. To semi-quantify MUC5B and MUC7 in the gels, a standard curve was generated using serially diluted purified mucin fractions of known concentrations (Malmö University, Sweden). The purified mucin fractions were serially diluted, subjected to electrophoresis, and stained with PAS. Images of the PAS-stained gel were analysed for band intensity using the ChemiDoc. Standard curves and linear equations were created for MUC5B and MUC7 concentrations against pixel intensity. The mucin concentrations of the samples were determined from the known pixel intensities using the linear equations derived from each standard curve (Fig. 1 ). The gels were scanned with the automated image-developing system, the ChemiDoc MP Imaging System (Bio-Rad, Hemel Hempstead, UK). They were then analysed in duplicate using the ChemiDoc Complementary Software, ImageLab (version 6.0 build 16; Bio-Rad, Hemel Hempstead, UK). α-Amylase analysis activity α-Amylase enzymatic activity was assessed using a commercial α-amylase kinetic assay (Sialimetrics LLC, PA, USA). The absorbance was measured at 405 nm at two time points (1 and 2 minutes) using a plate reader (iMark Microplate Absorbance Reader, BIO-RAD, UK). Samples were analysed in duplicates. Albumin analysis via sandwich enzyme-linked immunosorbent assay (ELISA) ELISA plates were coated overnight with an albumin capture antibody (Duo-Set ELISA, R&D Systems, Minneapolis, USA) and washed three times with phosphate-buffered saline containing Tween (PBS-T). The plates were then blocked with 1% BSA in PBS (pH 7.2) for one hour, followed by three additional washes with PBS-T. The samples and standards were diluted and incubated at room temperature for two hours, followed by three PBS-T washes. Biotinylated mouse antihuman serum albumin detection antibody, diluted in 1% BSA in PBS, was added to the samples and incubated at room temperature for 2 hours, followed by three PBS-T washes. Diluted horseradish peroxidase-conjugated streptavidin in 1% BSA in PBS was added to the samples at room temperature, and then the samples were washed three times with PBS-T. A substrate solution (tetramethylbenzidine) was added to the wells, and 2 M sulfuric acid was added after 5 minutes to stop the reaction. Finally, the plates were read at 400 nm using a plate reader (iMark Microplate Absorbance Reader, BIO-RAD, UK). The samples were analysed in duplicates. Cystatin S analysis using sandwich ELISA Cystatin S (CST4, Sandwich Cloud Clone Corp., USA), precoated with a specific antihuman polyclonal antibody to cystatin S, was used in this study. The samples were diluted 1:500 in ultra-high-quality water in duplicate, along with the standard, and incubated at 37°c for 1 hour. The liquid was then removed from each well. The biotinylated mouse antihuman serum cystatin S detection antibody was diluted in the assay diluent, added to the samples, incubated at 37°C for one hour, and then washed three times with wash solution diluted in ultra-pure water (1:30). Horseradish peroxidase-conjugated streptavidin was added to the samples for 30 minutes at 37°C, followed by five washes. A substrate solution of H2O2 and tetramethylbenzidine (1:1) was added to the samples and incubated for 20 min at 37°C. The reaction was stopped with 2 M sulfuric acid, and the plates were read at 450 nm using an iMark Microplate Absorbance Reader (BIO-RAD, UK). Clinical assessment of carious lesions Before undergoing cancer treatment, all HNC patients underwent a mandatory dental assessment in accordance with dental care recommendations. The clinical assessment for both groups included a clinical exam performed by the same consultant at the special dental care clinic and on the surgical floor under suitable conditions. Dental specialists were calibrated (Kappa index > 0.80) for caries detection (DMFT) using the criteria from the Adult Dental Health Survey (O'Sullivan, 2011). A panoramic or periapical radiograph was taken as part of the routine exam. Dental exam The dental examination was performed in accordance with the WHO guidelines to assess the DMFT index. enamel lesions on accessible surfaces, dentine lesions, both non-cavitated and cavitated, were included; missing teeth due to extraction were recorded; the presence of sound or healthy teeth was also recorded. This method relies on the examiner’s clinical experience; however, it is rapid, inexpensive, and has been used worldwide in epidemiology for more than 80 years [ 37 , 38 ] . Sound tooth: a tooth without visible caries after cleaning and drying the surfaces. Carious lesion: The carious lesion threshold was defined as follows: D1, an incipient enamel lesion with an intact surface; D2, a cavitated enamel lesion; and D3, a clinically detectable dentine lesion with cavitated enamel and exposed dentine (38–40). All of the above were compared across groups. Sample Size and Data Analysis. Since this is an exploratory pilot study, the sample size was based on previous research [ 39 – 41 ] concerning dental status outcomes and salivary protein parameters. The study used convenience, non-probability sampling, enrolling 40 HNC patients and 29 age- and sex-matched non-cancer individuals who met the inclusion criteria over a 12-month period, depending on clinic flow and eligibility. Due to the study having limited power as a preliminary step for further research Statistical analysis Continuous variables were tested for normality using the Shapiro–Wilk test, which indicated non-normality (p < 0.05) for all continuous variables. Therefore, results are presented as medians and interquartile ranges (IQRs) for continuous variables and as n (%) for categorical variables. Differences between groups in salivary flow rate, protein concentrations, and clinical dental outcomes were assessed using the Mann-Whitney test. Linear regression models with robust standard errors were developed to assess the association between HNC status and salivary gland function parameters, as well as specific salivary proteins. We developed two models, crude and adjusted for smoking status, with HNC as a binary variable (HNC = 1, non-cancer control = 0). Regression coefficients (β) with 95% confidence intervals (CI) were reported. Similarly, a logistic regression model was performed within the HNC cohort to evaluate the association between salivary parameters and the presence of at least one caries lesion ( > = 1), reporting odds ratios (OR) with 95% confidence intervals, and p-values were calculated for both crude and smoking-adjusted models. Crude models are univariable logistic regression analyses that examine the relationship between each selected salivary protein and the presence of caries lesions (at least one). Adjusted models include smoking status as a covariate. The smoking OR reflects the independent effect of smoking on caries risk within the adjusted model. All analyses were performed using Stata 19 (College Station, Texas, USA), GraphPad Prism 8 (La Jolla, California, USA), and Microsoft Excel 2018. Analyses were exploratory; the p-value was set at p < 0.05 for significance. 3. Results Baseline Characteristics Demographics, tumour characteristics, and lifestyle factors are shown in Table 1 . Age did not differ significantly between groups (p = 0.0789). The mean age of both groups was 59.12 (SD ± 10.19). Most participants were male, representing 88.9% of the HNC group and 87.5% of controls, with three females in the HNC group and four females in the age- and sex-matched controls. Most of the HNC cases were advanced in stage, with 61% stage IV disease. Medication use was significantly higher in the HNC group (p = 0.0016). Table 1 Demographics and clinical characteristics of the HNC patients and the age and sex matched controls. Variables HNC Total (n = 40) Number of patients (%) Non-Cancer (n = 28) Age, median (IQR) 56 (14.25) 55 (12.75) |Sex Female 4 (10%) 4 (14.2%) Male 36 (90%) 24 (85.8%) Cancer stage Stage I 1 (2.77%) - Stage II 7 (19.44%) - Stage III 6 (16.67%) - Stage IV 22 (61.11%) - Primary Tumour histology Squamous cell carcinoma 38(95%) - Adenocarcinoma 1 (2.5%) - Unknown 1 (2.55) - Smoking Nonsmoking 9 (25%) 22 (91.67%) Smoking 27 (75%) 2 (8.33%) Teeth number 23 (6,32) 27.5 (10,32) Caries teeth number 3.0 (0,12) 2 (0,6) Lost teeth number 8.0 (0, 24) 4 (0,22) Filled teeth number 7.0 (0, 20) 4 (0,15) Caries or filled teeth number 10.0 (1, 22) 5.5 (0,18) Healthy teeth number 12.0 (0,27) 21.5 (5, 30) Data are presented as frequencies (%) or medians, with minimum and maximum values. Dental assessment: presence of caries lesions. Dental clinical caries outcomes showed poorer dental status in the HNC group. HNC patients had fewer teeth (p = 0.074) and significantly more teeth with caries lesions (p = 0.050; 37/40 (92.5%) in HNC versus 20/29 (68%) in the non-cancer controls; see Fig. 2 . Healthy teeth were notably fewer in HNC (p = 0.0016, median 12 in the non-cancer group versus 21.5 teeth in HNC patients). Filled teeth showed no difference (p = 0.145). The combined number of decayed and filled teeth was significantly greater in HNC (p = 0.0019, median 10 versus 5.5 teeth). ( Fig. 2 ) The number of teeth with carious lesions was higher in HNC patients (p = 0.0502), nearly reaching statistical significance, with a median of 3 lesions ( Fig. 2 ). Among HNC patients, those with at least one caries lesion had significantly lower MUC7 concentrations in the crude analysis (OR = 0.92; 95% CI 0.85–1.00; p = 0.039), whereas MUC7 secretion rate was not significantly associated with caries presence (Table 4 ) Table 4 Predictors of caries presence (at least one ) in HNC patients: crude and smoking-adjusted logistic regression models (ORs). Outcome: Presence of caries (≥ 1), restricted to HNC patients. Predictor OR (95% CI) (crude) p-value OR (95% CI) (adjusted) p-value Smoking OR (95% CI) p-value Salivary gland function SFR (mL/min) 274278.2 (0.01, 8.7 x10 12 ) 0.156 1615.451 (0.001, 3.46 x10 9 0.321 2.85 (0.15, 56.02) 0.49 TPC (µg/mL) 1.23 (0.45, 3.38) 0.683 0.89 (0.37, 2.18) 0.806 1.03 (0.04, 27.57) 0.986 TPS (µg/min) 16.33 (0.29, 913.91) 0.174 2.86 (0.09, 94.73) 0.555 0.72 (0.02, 22.71) 0.85 Specific salivary proteins MUC5B concentration (µg/mL) 1.03 (0.95, 1.12) 0.507 0.98 (0.93, 1.03) 0.468 1.71 (0.04, 69.60) 0.776 MUC5B secretion rate (µg/min) 1.21 (0.83, 1.75) 0.316 0.98 (0.89, 1.08) 0.687 2.56 (0.05, 121.28) 0.633 MUC7 concentration (µg/mL) 0.92 (0.85, 1.00) 0.039 0.94 (0.87, 1.01) 0.072 2.34 (0.05, 104.13) 0.661 MUC7 secretion rate (µg/min) 0.89 (0.74, 1.06) 0.180 0.88 (0.76, 1.03) 0.110 1.57 (0.05, 52.61) 0.802 Albumin concentration (µg/mL) 1 (0.98, 1.02) 0.909 1 (0.98, 1.01) 0.606 4.17 (0.2, 85.41) 0.355 Albumin secretion rate (µg/min) 1.02 (0.96, 1.08) 0.6 1 (0.95, 1.05) 0.983 3.6 (0.18, 71.91) 0.402 Cystatin S concentration (µg/mL) 1 (0.83, 1.21) 0.99 0.84 (0.66, 1.07) 0.157 2.93 (0.12, 69.33) 0.505 Cystatin S secretion rate (µg/min) 1.04 (0.82, 1.32) 0.743 0.94 (0.74, 1.21) 0.647 3.80 (0.19, 74.16) 0.378 α-amylase concentration (U/mL) 1.01 (0.97, 1.05) 0.604 1 (0.98, 1.01) 0.83 1.02 (0.04, 25.70) 0.992 α-amylase secretion rate (U/min) 1.05 (0.92, 1.19) 0.47 1.01 (0.96, 1.06) 0.748 0.85 (0.03, 21.77) 0.919 Odds ratios (OR) and 95% confidence intervals (CI) are reported per 1-unit increase in each predictor. Model 1 is univariable (crude). Model 2 is adjusted for smoking (tobacco). Analyses are restricted to HNC patients (cancer = = 1). The very large odds ratio observed for SFR reflects model instability due to limited variability in the predictor and high outcome prevalence and should be interpreted with caution. Purified mucins with their linear equations were used to determine the concentration of MUC5B and MUC7 in various test samples. Both mucin bands were transformed into peaks, and the area under each curve represented the pixel intensity. The total number of teeth was lower in HNC patients (p = 0.074) than in the control group; however, the difference was not statistically significant. The number of healthy teeth was significantly higher in the non-cancer control group (p = 0.0016). The number of filled and decayed teeth was significantly higher in the HNC group (p = 0.0019). Data are shown as means ± SEM. Salivary gland function: salivary flow rate and content Table 2 summarises salivary gland function, including flow rate, total and selected salivary protein concentrations, and secretion rates among groups. Table 2 Salivary gland function and salivary biomarkers in head and neck cancer (HNC) patients pre-IMRT and non-cancer controls. Variable HNC pre-IMRT Median (IQR) Control Median (IQR) p-value (Mann–Whitney U) Salivary gland function Unstimulated salivary flow rate (SFR; mL/min) 0.45 (0.29) 0.55 (0.19) p = 0.12 Total protein concentration (TPC; µg/mL) 1.96 (1.6) 2.13 (1.69) p = 0.82 Total protein secretion rate (TPS; µg/min) 1.09 (1.87) 1.17 (1.12) p = 0.17 Specific salivary proteins MUC5B concentration (µg/mL) 72.09 (32.93) 111.31 (55.78) p < 0.0001 MUC5B secretion rate (µg/min) 33.56 (27.16) 63.31 (43.57) p = 0.0002 MUC7 concentration (µg/mL) 1.82 (1.87) 42.19 (52.39) p = 0.0001 MUC7 secretion rate (µg/min) 1.33 (1.23) 14.67 (26.65) p < 0.0001 Albumin concentration (µg/mL) 23.55 (67.43) 7.98 (11.03) p = 0.009 Albumin secretion rate (µg/min) 15.53 (26.14) 5.54 (5.46) p = 0.02 Cystatin S concentration (µg/mL) 12.97 (5.64) 15.74 (2.34) p = 0.59 Cystatin S secretion rate (µg/min) 8.68 (6.87) 8.96 (2.98) p = 0.14 α-amylase concentration (U/mL) 78.15 (78.8) 92.39 (73.77) p = 0.43 α-amylase secretion rate (U/min) 31.88 (42.19) 56.7 (42.1) p = 0.11 Shapiro–Wilk tests indicated non-normality for all continuous variables (p < 0.05); results are reported as medians (IQRs) and compared using the Mann–Whitney U test. Slivary flow rate The unstimulated salivary flow rate (SFR) did not differ between the HNC patients prior to IMRT and the age- and sex-matched controls (p = 0.12). The median salivary flow rate was slightly lower in HNC patients than in controls, although this difference was not statistically significant. Total protein concentration and secretion rate Similarly, total protein concentration (p = 0.82) and secretion rate (p = 0.17) were not significantly different between the groups (Table 2 ). Specific Salivary Protein concentration and secretion rate assessment. HNC patients exhibited lower MUC5B concentrations and secretion rates than non-cancer controls; the median MUC5B secretion rate was approximately half that of the controls. Similar reductions were observed in MUC7 concentration and secretion rate, both of which were significantly reduced in HNC patients. In contrast, albumin concentration (23.55 vs 7.98 µg/mL) and secretion rate (15.53 vs 5.54 µg/min) were significantly higher in HNC patients. There were no statistically significant differences for Cystatin S concentration and secretion rate, though the median was lower in HNC (8.68 vs 8.96 µg/min). Similarly, α-amylase concentration and secretion rate did not differ. (Table 2 ) Regression analysis of HNC association with specific salivary proteins Linear regression models were performed to evaluate the association between head and neck cancer status and salivary parameters. β coefficients indicate the average difference in each salivary parameter associated with HNC status relative to the control group. Crude models only include cancer status, while adjusted models account for both cancer status and smoking. The smoking β signifies the independent link between smoking and each salivary parameter. SFR was slightly lower in HNC but not significantly; TPC was not significantly different. However, TPS was significantly reduced after adjusting for smoking. In crude models, HNC presence was significantly associated with MUC5B and MUC7 concentration and secretion rate. MUC5B concentration and secretion rate were significantly lower in HNC patients. Similar reductions were observed for MUC7, where both concentration and secretion rate were significantly decreased. Suggesting that reductions in both mucins were associated with cancer status itself. These associations continued to be significant after smoking status was adjusted, indicating that these reductions were independent of smoking in HNC patients. Adjusted models reported significantly reduced MUC5B and MUC7 concentrations and secretion rates. (Table 3 ) Table 3 Linear regression of salivary gland function parameters and salivary biomarkers on cancer status (crude and adjusted for smoking), robust SEs Outcome β (95% CI) (crude) p-value β (95% CI) (adjusted) p-value Smoking β (95% CI) p-value Salivary gland function SFR (mL/min) −0.10 (− 0.22, 0.03) 0.139 −0.17 (− 0.38, 0.04) 0.108 0.10 (− 0.09, 0.30) 0.295 TPC (µg/mL) 0.09 (− 0.70, 0.88) 0.823 −0.22 (− 1.08, 0.64) 0.614 0.58 (− 0.34, 1.50) 0.21 TPS (µg/min) −0.23 (− 0.58, 0.11) 0.185 −0.60 (− 1.12, − 0.09) 0.022 0.59 (0.09, 1.08) 0.022 Specific salivary proteins MUC5B concentration (µg/mL) −73.16 (− 113.8, − 32.5) 0.001 −58.10 (− 99.66, − 16.55) 0.007 −24.52 (− 48.30, − 0.74) 0.044 MUC5B secretion rate (µg/min) −42.91 (− 71.06, − 14.75) 0.003 −45.80 (− 75.22, − 16.38) 0.003 −2.55 (− 18.08, 12.98) 0.744 MUC7 concentration (µg/mL) −34.69 (− 50.08, − 19.29) < 0.001 −35.55 (− 49.21, − 21.90) < 0.001 3.25 (− 3.88, 10.39) 0.365 MUC7 secretion rate (µg/min) −15.26 (− 22.64, − 7.88) < 0.001 −19.33 (− 27.02, − 11.64) < 0.001 5.03 (0.71, 9.34) 0.023 Albumin concentration (µg/mL) 37.59 (10.83, 64.34) 0.007 29.19 (− 1.08, 59.45) 0.058 12.67 (− 23.67, 49.00) 0.488 Albumin secretion rate (µg/min) 16.39 (4.25, 28.52) 0.009 9.53 (0.57, 18.49) 0.038 10.12 (− 3.11, 23.34) 0.131 Cystatin S concentration (µg/mL) −0.97 (− 3.26, 1.33) 0.404 −0.91 (− 6.13, 4.31) 0.729 0.13 (− 5.37, 5.62) 0.963 Cystatin S secretion rate (µg/min) −1.86 (− 4.78, 1.05) 0.205 −3.41 (− 7.17, 0.36) 0.075 1.72 (− 1.98, 5.42) 0.355 α-amylase concentration (U/mL) −5.59 (− 45.36, 34.18) 0.78 −5.14 ( − 57.32, 47.05) 0.844 0.28 (− 53.93, 54.49) 0.992 α-amylase secretion rate (U/min) −12.51 (− 31.21, 6.20) 0.186 −27.96 (− 52.76, − 3.16) 0.028 19.70 (− 4.83, 44.23) 0.113 β coefficients are from linear regression models with robust standard errors. Model 1 includes cancer status only; Model 2 includes cancer status and smoking (tobacco). Cancer is coded as 1 = cancer and 0 = control. Conversely, albumin concentration and secretion rate were significantly higher in HNC patients. After adjusting for smoking status, the association remained significant for the albumin secretion rate, while the concentration was only marginally non-significant. These results indicate possible increased mucosal permeability or inflammatory activity in patients with HNC. Non-significant associations were observed with cystatin S, whereas α-amylase secretion rate was significantly lower after adjustment for smoking status, which affects this protein output (Table 3 ). Dental assessment: Caries presence (at least 1) in HNC association with salivary gland function and salivary proteins concentration and secretion rate. Logistic regression models were used to assess the relationship between salivary gland flow rate, salivary proteins, and the presence of caries (at least one lesion). Salivary gland function parameters (SFR, TPC, and TPSR) were not significantly associated with caries presence in the crude and smoking-adjusted models. (Table 4 ) Among the analysed molecules, MUC7 concentration was the only salivary protein significantly associated with caries in the unadjusted analysis. MUC7 concentration showed a protective association (OR = 0.92; 95% CI, 0.85-1.00) in this study, suggesting that higher MUC7 levels were associated with lower odds of developing caries. (Table 4 ) 4. Discussion This study reported that salivary protein composition and secretion rate are significantly altered in HNC before radiotherapy. Specifically, significant reductions in MUC5B and MUC7 concentrations and secretion rates were observed, alongside increased albumin levels, despite similar unstimulated flow rates and total protein concentrations. These findings indicate that qualitative changes in salivary composition occur during cancer progression and are not solely a consequence of radiotherapy-induced salivary gland dysfunction [ 10 , 12 ] . MUC5B and MUC7 are core components of the pellicle, contributing to lubrication and microbial regulation (29,41). Their reduction contributes to an increased risk of radiation-induced caries [ 10 , 12 , 29 ][ 21 , 26 , 29 , 42 ] and may impair oral homeostasis, compromising oral defence. This provides a possible mechanism link between altered salivary composition and oral health outcomes in patients with HNC. This study demonstrated that HNC patients have poorer dental status than controls, with more teeth exhibiting carious lesions and fewer healthy teeth, consistent with previous studies in HNC patients before radiotherapy [ 17 , 43 ] . Moreover, the observed association between reduced MUC7 concentration and the presence of caries lesions supports the role of mucins in maintaining oral health. Although this association was not statistically significant after adjustment, this trend aligns with previously reported [ 44 – 46 ] and suggests a biologically relevant trend that merits further investigation in larger cohorts. The significantly elevated albumin levels may reflect increased epithelial permeability or subclinical inflammation [ 29 ] [ 33 ] , consistent with previous studies, in HNC patients before radiotherapy; however, this needs confirmation through longitudinal assessments of inflammatory markers. [ 47 ] α-Amylase and cystatin S levels did not differ between groups, suggesting that not all salivary proteins are equally affected and that alterations may be selective for certain proteins, particularly mucins. The unchanged total protein secretion rate supports that specific pathways may be altered in HNC patients rather than a generalised reduction in salivary protein secretion. Smoking status showed significant differences between groups; however, the associations between HNC and reduced levels of MUC5B and MUC7 persisted after adjustment, suggesting that these variations are likely related to the underlying disease process. Although previous reports have suggested that smoking can alter salivary composition and caries risk [ 48 ] , no independent association with the presence of carious lesions was observed in this study. Only MUC7 concentration showed a significant association with the presence of carious lesions in the crude model, suggesting a potential protective effect, although this association did not continue statistically significant after adjustment for smoking. These findings imply that the relationship between salivary proteins, tobacco exposure, and caries risk in HNC patients may be complex and multifactorial [ 48 , 49 ] . However, previous reports of Jiang et al. (2019) established a relationship between smoking and dental caries risk in the non-cancer population [ 50 ] . The lack of association reported in this study should be interpreted with caution and confirmed in larger studies, given the limited sample size and potential influences of additional factors, such as oral hygiene habits, diet, or cancer-related effects in the oral environment. Finally, our findings suggest that qualitative alterations in salivary composition precede radiotherapy rather than being solely attributable to it. Early identification of these changes could help guide preventive strategies to modify conventional clinical protocols. 5. Limitations The study design presents limitations that should be considered when interpreting the results. First, this is a cross-sectional study offering a snapshot of salivary composition in HNC patients before IMRT, complementing earlier publications that follow these patients after cancer treatment. However, it cannot establish a causal link between salivary proteins and caries lesion outcomes. Longitudinal studies are required to determine if these alterations predict post-treatment side effects. Second, the sample size was relatively small, reflecting the challenges of recruiting HNC patients before treatment. However, consistent differences in mucin concentration and secretion rate were reported, and the limited sample size may have reduced statistical power for some associations, particularly in multivariate models. In addition, residual confounding cannot be excluded because detailed information on lifestyle and host factors (such as nutritional status, systemic inflammation, stress levels, and alcohol consumption) was unavailable for all participants. These variables may influence salivary composition and contribute to the observed protein profiles. Regarding a mechanistic perspective, this study focused on salivary protein composition and did not include oral microbiome assessment, pellicle structure or salivary rheological properties. Future studies should integrate these parameters to provide a more comprehensive understanding of the biological consequences of mucin alterations. Finally, the carious lesion recording system is based on clinical examination, which may be affected by inter-examiner variability because it relies on the clinician’s knowledge and experience. However, there was a calibration between examiners who participated in this study. Despite these limitations, the study’s findings of a consistent reduction in both mucin concentration and secretion rate support the findings and highlight a biological alteration in salivary composition before radiotherapy. 6. Conclusion This study reports significant alterations in salivary proteins in HNC patients before the commencement of IMRT, characterised by reduced MUC5B and MUC7 concentrations and secretion rates, and increased albumin levels. These findings suggest that saliva composition is altered before radiotherapy, despite the preserved salivary flow rate. Mucin reduction may compromise the oral protection mechanism and contribute to the poor oral health status observed in the HNC patients. These results emphasise the potential benefit of using a salivary compositional assessment before radiotherapy to identify patients at high risk of oral complications and to support the development of targeted preventive strategies. Although the cross-sectional design limits causal inference, this study provides novel insight into salivary alterations in patients with head and neck cancer. Further longitudinal and mechanistic studies are required to clarify the clinical significance of these protein changes and their role in the development of oral diseases. Declarations Ethical Approval and consent to participate. Ethical approval was granted by the North Scotland Research Ethics Service Committee (REC reference: 16/NS/0116, IRAS Project ID:199100) in October 2016. Informed written consent was obtained from all participants before the study commenced, including for data publication. Adverse event reports would follow UK guidelines [51,52] ; however, there were no adverse events or safety concerns during the study period. Consent to Publication Not applicable Data Availability statement The data were submitted to the Research Data Protection Registration at King’s College London’s research governance, KDPR Registration Reference: DPRF-17/18-6377. Research data are stored in an institutional repository and will be shared upon request to the corresponding author. Funding The research leading to these results received funding from Agencia Nacional de Investigación y Desarrollo, Chile, under Grant Agreement No. 6694/201 Conflict of Interest : None Author contribution Dr Maria Gonzalez A: ( Corresponding Author ) This study is a part of a thesis submitted for the degree of Doctor of Philosophy. Dr Sophie S Bozorgi: Experimental methodology, review and editing. Nicolas Olivares: analysis, review, and editing. Professor Guy H Carpenter: Analysis, review, and editing. 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Oral prehabilitation for patients with head and neck cancer: getting it right - the Restorative Dentistry-UK consensus on a multidisciplinary approach to oral and dental assessment and planning prior to cancer treatment. British Dental Journal , 233 (9), 794–800. https://doi.org/10.1038/s41415-022-5197-3 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 13 May, 2026 Reviewers agreed at journal 05 May, 2026 Reviewers invited by journal 05 May, 2026 Editor assigned by journal 02 May, 2026 Submission checks completed at journal 29 Apr, 2026 First submitted to journal 28 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Both mucin bands were transformed into peaks, and the area under each curve represented the pixel intensity.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-9558012/v1/681fb97cb62bf1e119a4d9a2.jpeg"},{"id":109263601,"identity":"0d377441-99eb-4863-a118-8c02c1da408f","added_by":"auto","created_at":"2026-05-14 12:06:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":237486,"visible":true,"origin":"","legend":"\u003cp\u003eDental outcomes in HNC patients and non-cancer controls.\u003c/p\u003e\n\u003cp\u003eThe total number of teeth was lower in HNC patients (p = 0.074) than in the control group; however, the difference was not statistically significant. The number of healthy teeth was significantly higher in the non-cancer control group (p = 0.0016). The number of filled and decayed teeth was significantly higher in the HNC group (p = 0.0019). Data are shown as means ± SEM.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9558012/v1/3512c52e388155fc0537d29a.png"},{"id":109296259,"identity":"9154a1da-b431-436e-b1ca-bc774f2717be","added_by":"auto","created_at":"2026-05-15 08:46:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":744403,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9558012/v1/f15218a3-df4a-46c6-aefc-818be5dca499.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Altered salivary mucin composition in head and neck cancer patients prior to radiotherapy and its clinical implications for oral health","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eHead and neck cancers (HNCs) are the sixth most common malignancy globally, accounting for approximately 4\u0026ndash;5% of all cases \u003csup\u003e[\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. Oral squamous cell carcinoma (OSCC) accounts for 80 to 90% of head and neck cancers \u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Despite advances in diagnosis and treatment, many cases are often diagnosed at later stages, leading to significant morbidity (Cancer Research UK, 2023; Pfister et al., 2020). Radiotherapy, particularly intensity-modulated radiation therapy (IMRT), plays a fundamental role in HNC treatment; however, it is associated with debilitating oral side effects, comprising salivary gland dysfunction, xerostomia, radiotherapy-induced caries, and osteoradionecrosis, all of which impair quality of life \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13 CR14\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSalivary proteins are vital for dental health through lubrication, pellicle formation, antimicrobial activity, and mineral homeostasis. These functions influence bacterial colonisation and the development of carious lesions \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePrevious studies have demonstrated an association between total salivary protein concentration and radiation-induced caries (RC) \u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e; however, the specific pre-treatment salivary protein profile associated with caries risk in HNC remains unclear. This is important due to the poor oral health status among HNC patients prior to treatment initiation\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAmong salivary glycoproteins, MUC5B and MUC7 contribute to lubrication and microbial regulation, serving as the first line of defence in the mouth \u003csup\u003e[\u003cspan additionalcitationids=\"CR19 CR20 CR21 CR22 CR23 CR24\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. Altered mucin concentration or function may disrupt oral homeostasis and promote microbial dysbiosis \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e, increasing caries risk \u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. Other salivary proteins are also associated with caries risk. α-amylase, contributes to microbial metabolism \u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e, biofilm formation and bacterial adhesion \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan additionalcitationids=\"CR29 CR30 CR31\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e. Albumin reflects gland epithelial permeability and inflammation \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Cystatin S plays a role in remineralisation\u003csup\u003e[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e and in antibacterial defence. Cystatin S level has been associated with caries risk \u003csup\u003e[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHowever, their role in HNC patient\u0026rsquo;s pre-treatment remains unclear.\u003c/p\u003e \u003cp\u003eTo date, no studies have comprehensively characterised the pre-treatment salivary protein profile in HNC patients in association with caries lesions\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAim\u003c/strong\u003e \u003cp\u003eThis cross-sectional study aimed to compare salivary protein composition and secretion rates between HNC patients before IMRT and in age- and sex-matched non-cancer controls and to assess their association with caries lesions.\u003c/p\u003e \u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003e \u003cb\u003eStudy design\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA Cross-sectional study of HNC patients was conducted over 12 months at Guy\u0026rsquo;s and St Thomas\u0026rsquo; Hospital National Health Service (NHS) Foundation Trust, London, UK. HNC patients were assessed before the initiation of IMRT and compared with age and sex matched controls, non-cancer controls.\u003c/p\u003e \u003cp\u003e \u003cb\u003eOutcomes measured\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eTo evaluate the differences in caries lesion presence of head and neck cancer patients pre-IMRT with age and sex matched controls, non-cancer controls.\u003c/p\u003e \u003cp\u003eTo assess salivary flow rate, protein composition and secretion rates between HNC patients before IMRT and in age- and sex-matched non-cancer controls and the possible associations with caries lesions\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics approval\u003c/strong\u003e \u003cp\u003e The North Scotland Research Ethics Service Committee approved the study (16/NS/0116, IRAS Project ID: 199,100). All participants provided written informed consent. Adverse events were reported in accordance with UK guidelines. However, no adverse events or safety concerns were reported during the study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eData of the Study\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eThis study was submitted to the Research Data Protection Registration at King\u0026rsquo;s College London Research Governance (KDPR). Registration Reference: DPRF-17/18-6377.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePatient enrolment\u003c/b\u003e \u003c/p\u003e \u003cp\u003eWe consecutively enrolled forty dentate adults with HNC before starting IMRT, and 28 non-cancer control subjects at Guys and Thomas Foundation Trust (London, UK) over 12 months (February 2017 \u0026ndash; February 2018). Non-cancer controls were frequency matched to HNC cases by sex (male/female) and age (55\u0026ndash;70 years) at the group level. This resulted in a final number of 28 non-cancer subjects due to clinic workflow and eligibility criteria. Analysis used independent group methods for the final sample, with age and sex included where applicable.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInclusion criteria\u003c/strong\u003e \u003cp\u003ePatients aged 18 years or older, dentate (with at least one tooth) and with a permanent dentition were eligible. Confirmed HNC with no distant metastases, evaluated pre-IMRT. For the non-cancer control group, there was no history of head and neck cancer or radiotherapy/chemotherapy. Stable systemic diseases controlled by regular medication were included. Additionally, smoking and drinking habits were analysed in subjects.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eExclusion criteria\u003c/strong\u003e \u003cp\u003ePatients with Sjogren\u0026rsquo;s syndrome or other disorders that affect salivary flow rate, uncontrolled diabetes mellitus, uncontrolled hypertension, and those who have used antibiotics within the last three months. Patients receiving parenteral nutrition.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSample collection and biochemical analysis\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSaliva collection/assessment\u003c/b\u003e \u003c/p\u003e \u003cp\u003eUnstimulated Whole Mouth Saliva (UWMS) was collected by the passive drooling method for 10 minutes after a minimum of 60 minutes of fasting. Collection was performed regularly between 13:30 and 15:30 to minimise the potential effects of circadian variation. Samples were transported on ice to the laboratory, aliquoted, and centrifuged at 10,000 g for 5 minutes at 4\u0026deg;C. The aliquots were then stored at \u0026minus;\u0026thinsp;80\u0026deg;C. The Salivary flow rate (SFR) was calculated (volume per minute, mL/min).\u003c/p\u003e \u003cp\u003e \u003cb\u003eSalivary Biochemical assays\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eTotal protein concentration (TPC) analysis.\u003c/b\u003e Total protein concentration was assessed using a bicinchoninic acid assay (BCA) kit (Pierce, Rockford, IL, USA). Samples were evaluated in duplicate.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eTotal protein secretion rate (TPS) analysis\u003c/strong\u003e \u003cp\u003eThis was calculated by multiplying the salivary flow rate (mL/min) by the protein concentration (\u0026micro;g/mL), yielding the rate in \u0026micro;g/min. Furthermore, the secretion rate of each protein was calculated to quantify the amount delivered to the oral cavity.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSelected proteins analysis\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eMUC5B and 7 analyses.\u003c/b\u003e After determining the total protein concentration, mucins 5B and 7 were analysed by SDS-PAGE. 20 \u0026micro;g of salivary proteins were loaded onto NuPAGE Novex 4%\u0026ndash;12% bis-tris gels under reducing conditions and heated to separate the proteins by molecular weight. Mucins 5B and 7 were stained with polysaccharide periodic acid\u0026ndash;Schiff reagent to identify mucin glycosylation.\u003c/p\u003e \u003cp\u003eTo semi-quantify MUC5B and MUC7 in the gels, a standard curve was generated using serially diluted purified mucin fractions of known concentrations (Malm\u0026ouml; University, Sweden). The purified mucin fractions were serially diluted, subjected to electrophoresis, and stained with PAS. Images of the PAS-stained gel were analysed for band intensity using the ChemiDoc. Standard curves and linear equations were created for MUC5B and MUC7 concentrations against pixel intensity. The mucin concentrations of the samples were determined from the known pixel intensities using the linear equations derived from each standard curve (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The gels were scanned with the automated image-developing system, the ChemiDoc MP Imaging System (Bio-Rad, Hemel Hempstead, UK). They were then analysed in duplicate using the ChemiDoc Complementary Software, ImageLab (version 6.0 build 16; Bio-Rad, Hemel Hempstead, UK).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eα-Amylase analysis activity\u003c/b\u003e \u003c/p\u003e \u003cp\u003eα-Amylase enzymatic activity was assessed using a commercial α-amylase kinetic assay (Sialimetrics LLC, PA, USA). The absorbance was measured at 405 nm at two time points (1 and 2 minutes) using a plate reader (iMark Microplate Absorbance Reader, BIO-RAD, UK). Samples were analysed in duplicates.\u003c/p\u003e \u003cp\u003e \u003cb\u003eAlbumin analysis via sandwich enzyme-linked immunosorbent assay (ELISA)\u003c/b\u003e \u003c/p\u003e \u003cp\u003eELISA plates were coated overnight with an albumin capture antibody (Duo-Set ELISA, R\u0026amp;D Systems, Minneapolis, USA) and washed three times with phosphate-buffered saline containing Tween (PBS-T). The plates were then blocked with 1% BSA in PBS (pH 7.2) for one hour, followed by three additional washes with PBS-T. The samples and standards were diluted and incubated at room temperature for two hours, followed by three PBS-T washes.\u003c/p\u003e \u003cp\u003eBiotinylated mouse antihuman serum albumin detection antibody, diluted in 1% BSA in PBS, was added to the samples and incubated at room temperature for 2 hours, followed by three PBS-T washes. Diluted horseradish peroxidase-conjugated streptavidin in 1% BSA in PBS was added to the samples at room temperature, and then the samples were washed three times with PBS-T. A substrate solution (tetramethylbenzidine) was added to the wells, and 2 M sulfuric acid was added after 5 minutes to stop the reaction. Finally, the plates were read at 400 nm using a plate reader (iMark Microplate Absorbance Reader, BIO-RAD, UK). The samples were analysed in duplicates.\u003c/p\u003e \u003cp\u003e \u003cb\u003eCystatin S analysis using sandwich ELISA\u003c/b\u003e \u003c/p\u003e \u003cp\u003eCystatin S (CST4, Sandwich Cloud Clone Corp., USA), precoated with a specific antihuman polyclonal antibody to cystatin S, was used in this study. The samples were diluted 1:500 in ultra-high-quality water in duplicate, along with the standard, and incubated at 37\u0026deg;c for 1 hour. The liquid was then removed from each well. The biotinylated mouse antihuman serum cystatin S detection antibody was diluted in the assay diluent, added to the samples, incubated at 37\u0026deg;C for one hour, and then washed three times with wash solution diluted in ultra-pure water (1:30). Horseradish peroxidase-conjugated streptavidin was added to the samples for 30 minutes at 37\u0026deg;C, followed by five washes. A substrate solution of H2O2 and tetramethylbenzidine (1:1) was added to the samples and incubated for 20 min at 37\u0026deg;C. The reaction was stopped with 2 M sulfuric acid, and the plates were read at 450 nm using an iMark Microplate Absorbance Reader (BIO-RAD, UK).\u003c/p\u003e \u003cp\u003e \u003cb\u003eClinical assessment of carious lesions\u003c/b\u003e \u003c/p\u003e \u003cp\u003eBefore undergoing cancer treatment, all HNC patients underwent a mandatory dental assessment in accordance with dental care recommendations.\u003c/p\u003e \u003cp\u003eThe clinical assessment for both groups included a clinical exam performed by the same consultant at the special dental care clinic and on the surgical floor under suitable conditions. Dental specialists were calibrated (Kappa index\u0026thinsp;\u0026gt;\u0026thinsp;0.80) for caries detection (DMFT) using the criteria from the Adult Dental Health Survey (O'Sullivan, 2011). A panoramic or periapical radiograph was taken as part of the routine exam.\u003c/p\u003e \u003cp\u003e \u003cb\u003eDental exam\u003c/b\u003e \u003c/p\u003e \u003cp\u003e The dental examination was performed in accordance with the WHO guidelines to assess the DMFT index. enamel lesions on accessible surfaces, dentine lesions, both non-cavitated and cavitated, were included; missing teeth due to extraction were recorded; the presence of sound or healthy teeth was also recorded. This method relies on the examiner\u0026rsquo;s clinical experience; however, it is rapid, inexpensive, and has been used worldwide in epidemiology for more than 80 years \u003csup\u003e[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSound tooth: a tooth without visible caries after cleaning and drying the surfaces.\u003c/p\u003e \u003cp\u003eCarious lesion: The carious lesion threshold was defined as follows: D1, an incipient enamel lesion with an intact surface; D2, a cavitated enamel lesion; and D3, a clinically detectable dentine lesion with cavitated enamel and exposed dentine (38\u0026ndash;40).\u003c/p\u003e \u003cp\u003eAll of the above were compared across groups.\u003c/p\u003e \u003cp\u003e \u003cb\u003eSample Size and Data Analysis.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eSince this is an exploratory pilot study, the sample size was based on previous research \u003csup\u003e[\u003cspan additionalcitationids=\"CR40\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/sup\u003e concerning dental status outcomes and salivary protein parameters. The study used convenience, non-probability sampling, enrolling 40 HNC patients and 29 age- and sex-matched non-cancer individuals who met the inclusion criteria over a 12-month period, depending on clinic flow and eligibility. Due to the study having limited power as a preliminary step for further research\u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical analysis\u003c/b\u003e \u003c/p\u003e \u003cp\u003eContinuous variables were tested for normality using the Shapiro\u0026ndash;Wilk test, which indicated non-normality (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) for all continuous variables. Therefore, results are presented as medians and interquartile ranges (IQRs) for continuous variables and as n (%) for categorical variables.\u003c/p\u003e \u003cp\u003eDifferences between groups in salivary flow rate, protein concentrations, and clinical dental outcomes were assessed using the Mann-Whitney test.\u003c/p\u003e \u003cp\u003eLinear regression models with robust standard errors were developed to assess the association between HNC status and salivary gland function parameters, as well as specific salivary proteins. We developed two models, crude and adjusted for smoking status, with HNC as a binary variable (HNC\u0026thinsp;=\u0026thinsp;1, non-cancer control\u0026thinsp;=\u0026thinsp;0). Regression coefficients (β) with 95% confidence intervals (CI) were reported.\u003c/p\u003e \u003cp\u003eSimilarly, a logistic regression model was performed within the HNC cohort to evaluate the association between salivary parameters and the presence of at least one caries lesion (\u0026thinsp;\u0026gt;\u0026thinsp;=\u0026thinsp;1), reporting odds ratios (OR) with 95% confidence intervals, and p-values were calculated for both crude and smoking-adjusted models.\u003c/p\u003e \u003cp\u003eCrude models are univariable logistic regression analyses that examine the relationship between each selected salivary protein and the presence of caries lesions (at least one). Adjusted models include smoking status as a covariate. The smoking OR reflects the independent effect of smoking on caries risk within the adjusted model.\u003c/p\u003e \u003cp\u003eAll analyses were performed using Stata 19 (College Station, Texas, USA), GraphPad Prism 8 (La Jolla, California, USA), and Microsoft Excel 2018. Analyses were exploratory; the p-value was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 for significance.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003eBaseline Characteristics\u003c/b\u003e \u003c/p\u003e \u003cp\u003eDemographics, tumour characteristics, and lifestyle factors are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Age did not differ significantly between groups (p\u0026thinsp;=\u0026thinsp;0.0789). The mean age of both groups was 59.12 (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;10.19). Most participants were male, representing 88.9% of the HNC group and 87.5% of controls, with three females in the HNC group and four females in the age- and sex-matched controls. Most of the HNC cases were advanced in stage, with 61% stage IV disease. Medication use was significantly higher in the HNC group (p\u0026thinsp;=\u0026thinsp;0.0016).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographics and clinical characteristics of the HNC patients and the age and sex matched controls.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHNC Total (n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e \u003cp\u003eNumber of patients (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNon-Cancer\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;28)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, median (IQR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56 (14.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55 (12.75)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e|Sex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (14.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36 (90%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24 (85.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCancer stage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStage I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.77%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStage II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (19.44%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStage III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (16.67%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStage IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22 (61.11%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrimary Tumour histology\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSquamous cell carcinoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38(95%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdenocarcinoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNonsmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (91.67%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27 (75%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (8.33%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTeeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (6,32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27.5 (10,32)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaries teeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.0 (0,12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (0,6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLost teeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.0 (0, 24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (0,22)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFilled teeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.0 (0, 20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (0,15)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaries or filled teeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.0 (1, 22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.5 (0,18)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHealthy teeth number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.0 (0,27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.5 (5, 30)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eData are presented as frequencies (%) or medians, with minimum and maximum values.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eDental assessment: presence of caries lesions.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eDental clinical caries outcomes showed poorer dental status in the HNC group. HNC patients had fewer teeth (p\u0026thinsp;=\u0026thinsp;0.074) and significantly more teeth with caries lesions (p\u0026thinsp;=\u0026thinsp;0.050; 37/40 (92.5%) in HNC versus 20/29 (68%) in the non-cancer controls; see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Healthy teeth were notably fewer in HNC (p\u0026thinsp;=\u0026thinsp;0.0016, median 12 in the non-cancer group versus 21.5 teeth in HNC patients). Filled teeth showed no difference (p\u0026thinsp;=\u0026thinsp;0.145). The combined number of decayed and filled teeth was significantly greater in HNC (p\u0026thinsp;=\u0026thinsp;0.0019, median 10 versus 5.5 teeth). \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe number of teeth with carious lesions was higher in HNC patients (p\u0026thinsp;=\u0026thinsp;0.0502), nearly reaching statistical significance, with a median of 3 lesions \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e \u003cp\u003eAmong HNC patients, those with at least one caries lesion had significantly lower MUC7 concentrations in the crude analysis (OR\u0026thinsp;=\u0026thinsp;0.92; 95% CI 0.85\u0026ndash;1.00; p\u0026thinsp;=\u0026thinsp;0.039), whereas MUC7 secretion rate was not significantly associated with caries presence (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePredictors of caries presence (at least one ) in HNC patients: crude and smoking-adjusted logistic regression models (ORs). Outcome: Presence of caries (\u0026ge;\u0026thinsp;1), restricted to HNC patients.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePredictor\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003cp\u003e(crude)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003cp\u003e(adjusted)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSmoking OR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e \u003cp\u003eSalivary gland function\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSFR (mL/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e274278.2 \u003c/p\u003e \u003cp\u003e(0.01, 8.7 x10\u003csup\u003e12\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.156\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e1615.451 \u003c/p\u003e \u003cp\u003e(0.001, 3.46 x10\u003csup\u003e9\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.321\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.85\u003c/p\u003e \u003cp\u003e(0.15, 56.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTPC (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.23\u003c/p\u003e \u003cp\u003e(0.45, 3.38)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.683\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.89\u003c/p\u003e \u003cp\u003e(0.37, 2.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.806\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003cp\u003e(0.04, 27.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTPS (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.33\u003c/p\u003e \u003cp\u003e(0.29, 913.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.174\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e2.86\u003c/p\u003e \u003cp\u003e(0.09, 94.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.555\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.72\u003c/p\u003e \u003cp\u003e(0.02, 22.71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpecific salivary proteins\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003cp\u003e(0.95, 1.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.507\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003cp\u003e(0.93, 1.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.468\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.71 \u003c/p\u003e \u003cp\u003e(0.04, 69.60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.776\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.21\u003c/p\u003e \u003cp\u003e(0.83, 1.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.316\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003cp\u003e(0.89, 1.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.687\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.56\u003c/p\u003e \u003cp\u003e(0.05, 121.28)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.633\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabc\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.92\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(0.85, 1.00)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.039\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.94\u003c/p\u003e \u003cp\u003e(0.87, 1.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.072\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.34\u003c/p\u003e \u003cp\u003e(0.05, 104.13)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.661\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabd\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e0.89\u003c/p\u003e \u003cp\u003e(0.74, 1.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.180\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.88\u003c/p\u003e \u003cp\u003e(0.76, 1.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.57\u003c/p\u003e \u003cp\u003e(0.05, 52.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.802\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabe\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e(0.98, 1.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.909\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e(0.98, 1.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.606\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.17\u003c/p\u003e \u003cp\u003e(0.2, 85.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.355\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabf\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.02\u003c/p\u003e \u003cp\u003e(0.96, 1.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e(0.95, 1.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003cp\u003e(0.18, 71.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.402\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabg\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e(0.83, 1.21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003cp\u003e(0.66, 1.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.93\u003c/p\u003e \u003cp\u003e(0.12, 69.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.505\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabh\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.04\u003c/p\u003e \u003cp\u003e(0.82, 1.32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.743\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.94\u003c/p\u003e \u003cp\u003e(0.74, 1.21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.647\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3.80\u003c/p\u003e \u003cp\u003e(0.19, 74.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.378\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabi\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase concentration (U/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003cp\u003e(0.97, 1.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.604\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003cp\u003e(0.98, 1.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.02\u003c/p\u003e \u003cp\u003e(0.04, 25.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.992\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabj\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase secretion rate (U/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1.05\u003c/p\u003e \u003cp\u003e(0.92, 1.19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003cp\u003e(0.96, 1.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.748\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003cp\u003e(0.03, 21.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.919\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003e\u003cem\u003eOdds ratios (OR) and 95% confidence intervals (CI) are reported per 1-unit increase in each predictor. Model 1 is univariable (crude). Model 2 is adjusted for smoking (tobacco). Analyses are restricted to HNC patients (cancer\u0026thinsp;=\u0026thinsp;=\u0026thinsp;1).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003eThe very large odds ratio observed for SFR reflects model instability due to limited variability in the predictor and high outcome prevalence and should be interpreted with caution.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003ePurified mucins with their linear equations were used to determine the concentration of MUC5B and MUC7 in various test samples. Both mucin bands were transformed into peaks, and the area under each curve represented the pixel intensity.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003eThe total number of teeth was lower in HNC patients (p\u0026thinsp;=\u0026thinsp;0.074) than in the control group; however, the difference was not statistically significant. The number of healthy teeth was significantly higher in the non-cancer control group (p\u0026thinsp;=\u0026thinsp;0.0016). The number of filled and decayed teeth was significantly higher in the HNC group (p\u0026thinsp;=\u0026thinsp;0.0019). Data are shown as means\u0026thinsp;\u0026plusmn;\u0026thinsp;SEM.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSalivary gland function: salivary flow rate and content\u003c/b\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e summarises salivary gland function, including flow rate, total and selected salivary protein concentrations, and secretion rates among groups.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSalivary gland function and salivary biomarkers in head and neck cancer (HNC) patients pre-IMRT and non-cancer controls.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHNC pre-IMRT\u003c/p\u003e \u003cp\u003eMedian (IQR)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003cp\u003eMedian (IQR)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep-value (Mann\u0026ndash;Whitney U)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eSalivary gland function\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnstimulated salivary flow rate (SFR; mL/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.45 (0.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.55 (0.19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal protein concentration\u003c/p\u003e \u003cp\u003e(TPC; \u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.96 (1.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.13 (1.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal protein secretion rate\u003c/p\u003e \u003cp\u003e(TPS; \u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.09 (1.87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.17 (1.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpecific salivary proteins\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabk\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e72.09 (32.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e111.31 (55.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabl\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.56 (27.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e63.31 (43.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;=\u0026thinsp;0.0002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabm\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.82 (1.87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42.19 (52.39)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;=\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabn\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.33 (1.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.67 (26.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabo\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.55 (67.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.98 (11.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;=\u0026thinsp;0.009\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabp\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.53 (26.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.54 (5.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ep\u0026thinsp;=\u0026thinsp;0.02\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabq\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.97 (5.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.74 (2.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.59\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabr\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.68 (6.87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.96 (2.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabs\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase concentration (U/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78.15 (78.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e92.39 (73.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabt\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase secretion rate (U/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31.88 (42.19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e56.7 (42.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eShapiro\u0026ndash;Wilk tests indicated non-normality for all continuous variables (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05); results are reported as medians (IQRs) and compared using the Mann\u0026ndash;Whitney U test.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSlivary flow rate\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe unstimulated salivary flow rate (SFR) did not differ between the HNC patients prior to IMRT and the age- and sex-matched controls (p\u0026thinsp;=\u0026thinsp;0.12). The median salivary flow rate was slightly lower in HNC patients than in controls, although this difference was not statistically significant.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTotal protein concentration and secretion rate\u003c/b\u003e \u003c/p\u003e \u003cp\u003eSimilarly, total protein concentration (p\u0026thinsp;=\u0026thinsp;0.82) and secretion rate (p\u0026thinsp;=\u0026thinsp;0.17) were not significantly different between the groups (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cb\u003eSpecific Salivary Protein concentration and secretion rate assessment.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eHNC patients exhibited lower MUC5B concentrations and secretion rates than non-cancer controls; the median MUC5B secretion rate was approximately half that of the controls. Similar reductions were observed in MUC7 concentration and secretion rate, both of which were significantly reduced in HNC patients. In contrast, albumin concentration (23.55 vs 7.98 \u0026micro;g/mL) and secretion rate (15.53 vs 5.54 \u0026micro;g/min) were significantly higher in HNC patients. There were no statistically significant differences for Cystatin S concentration and secretion rate, though the median was lower in HNC (8.68 vs 8.96 \u0026micro;g/min). Similarly, α-amylase concentration and secretion rate did not differ. (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2\u003c/span\u003e )\u003c/p\u003e \u003cp\u003e \u003cb\u003eRegression analysis of HNC association with specific salivary proteins\u003c/b\u003e \u003c/p\u003e \u003cp\u003eLinear regression models were performed to evaluate the association between head and neck cancer status and salivary parameters. β coefficients indicate the average difference in each salivary parameter associated with HNC status relative to the control group. Crude models only include cancer status, while adjusted models account for both cancer status and smoking. The smoking β signifies the independent link between smoking and each salivary parameter.\u003c/p\u003e \u003cp\u003eSFR was slightly lower in HNC but not significantly; TPC was not significantly different. However, TPS was significantly reduced after adjusting for smoking.\u003c/p\u003e \u003cp\u003eIn crude models, HNC presence was significantly associated with MUC5B and MUC7 concentration and secretion rate.\u003c/p\u003e \u003cp\u003eMUC5B concentration and secretion rate were significantly lower in HNC patients. Similar reductions were observed for MUC7, where both concentration and secretion rate were significantly decreased. Suggesting that reductions in both mucins were associated with cancer status itself. These associations continued to be significant after smoking status was adjusted, indicating that these reductions were independent of smoking in HNC patients. Adjusted models reported significantly reduced MUC5B and MUC7 concentrations and secretion rates. (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eLinear regression of salivary gland function parameters and salivary biomarkers on cancer status (crude and adjusted for smoking), robust SEs\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutcome\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eβ (95% CI)\u003c/p\u003e \u003cp\u003e(crude)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eβ (95% CI)\u003c/p\u003e \u003cp\u003e(adjusted)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003cp\u003eβ (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e \u003cp\u003eSalivary gland function\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSFR (mL/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026minus;0.10 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.22, 0.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.139\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e\u0026minus;0.17 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.38, 0.04)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.108\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.10 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.09, 0.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.295\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTPC (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.09 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.70, 0.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.823\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e\u0026minus;0.22 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;1.08, 0.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.614\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.58 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.34, 1.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTPS (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026minus;0.23 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;0.58, 0.11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.185\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;0.60 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;1.12, \u0026minus;\u0026thinsp;0.09)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.022\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.59 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(0.09, 1.08)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.022\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpecific salivary proteins\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabu\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;73.16 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;113.8, \u0026minus;\u0026thinsp;32.5)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;58.10 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;99.66, \u0026minus;\u0026thinsp;16.55)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;24.52 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;48.30, \u0026minus;\u0026thinsp;0.74)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.044\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabv\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC5B secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;42.91 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;71.06, \u0026minus;\u0026thinsp;14.75)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.003\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;45.80 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;75.22, \u0026minus;\u0026thinsp;16.38)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.003\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026minus;2.55 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;18.08, 12.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.744\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabw\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;34.69 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;50.08, \u0026minus;\u0026thinsp;19.29)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;35.55 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;49.21, \u0026minus;\u0026thinsp;21.90)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3.25 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;3.88, 10.39)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.365\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabx\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMUC7 secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;15.26 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;22.64, \u0026minus;\u0026thinsp;7.88)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;19.33 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;27.02, \u0026minus;\u0026thinsp;11.64)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e5.03 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(0.71, 9.34)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.023\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taby\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e37.59 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(10.83, 64.34)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e29.19\u003c/p\u003e \u003cp\u003e (\u0026minus;\u0026thinsp;1.08, 59.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.058\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e12.67 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;23.67, 49.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.488\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabz\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u003cb\u003e16.39 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(4.25, 28.52)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.009\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e9.53 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(0.57, 18.49)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.038\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10.12 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;3.11, 23.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.131\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabaa\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S concentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u0026minus;0.97 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;3.26, 1.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.404\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;0.91 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;6.13, 4.31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.729\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.13 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;5.37, 5.62)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.963\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabab\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystatin S secretion rate (\u0026micro;g/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u0026minus;1.86 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;4.78, 1.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.205\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;3.41 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;7.17, 0.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.72 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;1.98, 5.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.355\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabac\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase concentration (U/mL)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u0026minus;5.59 (\u0026minus;\u0026thinsp;45.36, 34.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026minus;5.14 (\u003c/p\u003e \u003cp\u003e\u0026minus;\u0026thinsp;57.32, 47.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.844\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.28 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;53.93, 54.49)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.992\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabad\" border=\"1\"\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eα-amylase secretion rate (U/min)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u0026minus;12.51 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;31.21, 6.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e0.186\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026minus;27.96 \u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(\u0026minus;\u0026thinsp;52.76, \u0026minus;\u0026thinsp;3.16)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e0.028\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e19.70 \u003c/p\u003e \u003cp\u003e(\u0026minus;\u0026thinsp;4.83, 44.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.113\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003e\u003cem\u003eβ coefficients are from linear regression models with robust standard errors. Model 1 includes cancer status only; Model 2 includes cancer status and smoking (tobacco). Cancer is coded as 1\u0026thinsp;=\u0026thinsp;cancer and 0\u0026thinsp;=\u0026thinsp;control.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eConversely, albumin concentration and secretion rate were significantly higher in HNC patients. After adjusting for smoking status, the association remained significant for the albumin secretion rate, while the concentration was only marginally non-significant. These results indicate possible increased mucosal permeability or inflammatory activity in patients with HNC. Non-significant associations were observed with cystatin S, whereas α-amylase secretion rate was significantly lower after adjustment for smoking status, which affects this protein output (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003eDental assessment: Caries presence (at least 1) in HNC association with salivary gland function and salivary proteins concentration and secretion rate.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eLogistic regression models were used to assess the relationship between salivary gland flow rate, salivary proteins, and the presence of caries (at least one lesion). Salivary gland function parameters (SFR, TPC, and TPSR) were not significantly associated with caries presence in the crude and smoking-adjusted models. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eAmong the analysed molecules, MUC7 concentration was the only salivary protein significantly associated with caries in the unadjusted analysis. MUC7 concentration showed a protective association (OR\u0026thinsp;=\u0026thinsp;0.92; 95% CI, 0.85-1.00) in this study, suggesting that higher MUC7 levels were associated with lower odds of developing caries. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study reported that salivary protein composition and secretion rate are significantly altered in HNC before radiotherapy. Specifically, significant reductions in MUC5B and MUC7 concentrations and secretion rates were observed, alongside increased albumin levels, despite similar unstimulated flow rates and total protein concentrations. These findings indicate that qualitative changes in salivary composition occur during cancer progression and are not solely a consequence of radiotherapy-induced salivary gland dysfunction \u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMUC5B and MUC7 are core components of the pellicle, contributing to lubrication and microbial regulation (29,41). Their reduction contributes to an increased risk of radiation-induced caries\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e][\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/sup\u003e and may impair oral homeostasis, compromising oral defence. This provides a possible mechanism link between altered salivary composition and oral health outcomes in patients with HNC. This study demonstrated that HNC patients have poorer dental status than controls, with more teeth exhibiting carious lesions and fewer healthy teeth, consistent with previous studies in HNC patients before radiotherapy \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMoreover, the observed association between reduced MUC7 concentration and the presence of caries lesions supports the role of mucins in maintaining oral health. Although this association was not statistically significant after adjustment, this trend aligns with previously reported \u003csup\u003e[\u003cspan additionalcitationids=\"CR45\" citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]\u003c/sup\u003e and suggests a biologically relevant trend that merits further investigation in larger cohorts.\u003c/p\u003e \u003cp\u003eThe significantly elevated albumin levels may reflect increased epithelial permeability or subclinical inflammation \u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e, consistent with previous studies, in HNC patients before radiotherapy; however, this needs confirmation through longitudinal assessments of inflammatory markers. \u003csup\u003e[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eα-Amylase and cystatin S levels did not differ between groups, suggesting that not all salivary proteins are equally affected and that alterations may be selective for certain proteins, particularly mucins. The unchanged total protein secretion rate supports that specific pathways may be altered in HNC patients rather than a generalised reduction in salivary protein secretion.\u003c/p\u003e \u003cp\u003eSmoking status showed significant differences between groups; however, the associations between HNC and reduced levels of MUC5B and MUC7 persisted after adjustment, suggesting that these variations are likely related to the underlying disease process. Although previous reports have suggested that smoking can alter salivary composition and caries risk \u003csup\u003e[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]\u003c/sup\u003e, no independent association with the presence of carious lesions was observed in this study.\u003c/p\u003e \u003cp\u003eOnly MUC7 concentration showed a significant association with the presence of carious lesions in the crude model, suggesting a potential protective effect, although this association did not continue statistically significant after adjustment for smoking. These findings imply that the relationship between salivary proteins, tobacco exposure, and caries risk in HNC patients may be complex and multifactorial \u003csup\u003e[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]\u003c/sup\u003e. However, previous reports of Jiang et al. (2019) established a relationship between smoking and dental caries risk in the non-cancer population \u003csup\u003e[\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]\u003c/sup\u003e. The lack of association reported in this study should be interpreted with caution and confirmed in larger studies, given the limited sample size and potential influences of additional factors, such as oral hygiene habits, diet, or cancer-related effects in the oral environment.\u003c/p\u003e \u003cp\u003eFinally, our findings suggest that qualitative alterations in salivary composition precede radiotherapy rather than being solely attributable to it. Early identification of these changes could help guide preventive strategies to modify conventional clinical protocols.\u003c/p\u003e"},{"header":"5. Limitations","content":"\u003cp\u003eThe study design presents limitations that should be considered when interpreting the results.\u003c/p\u003e \u003cp\u003eFirst, this is a cross-sectional study offering a snapshot of salivary composition in HNC patients before IMRT, complementing earlier publications that follow these patients after cancer treatment. However, it cannot establish a causal link between salivary proteins and caries lesion outcomes. Longitudinal studies are required to determine if these alterations predict post-treatment side effects.\u003c/p\u003e \u003cp\u003eSecond, the sample size was relatively small, reflecting the challenges of recruiting HNC patients before treatment. However, consistent differences in mucin concentration and secretion rate were reported, and the limited sample size may have reduced statistical power for some associations, particularly in multivariate models.\u003c/p\u003e \u003cp\u003eIn addition, residual confounding cannot be excluded because detailed information on lifestyle and host factors (such as nutritional status, systemic inflammation, stress levels, and alcohol consumption) was unavailable for all participants. These variables may influence salivary composition and contribute to the observed protein profiles.\u003c/p\u003e \u003cp\u003e Regarding a mechanistic perspective, this study focused on salivary protein composition and did not include oral microbiome assessment, pellicle structure or salivary rheological properties. Future studies should integrate these parameters to provide a more comprehensive understanding of the biological consequences of mucin alterations.\u003c/p\u003e \u003cp\u003eFinally, the carious lesion recording system is based on clinical examination, which may be affected by inter-examiner variability because it relies on the clinician\u0026rsquo;s knowledge and experience. However, there was a calibration between examiners who participated in this study.\u003c/p\u003e \u003cp\u003eDespite these limitations, the study\u0026rsquo;s findings of a consistent reduction in both mucin concentration and secretion rate support the findings and highlight a biological alteration in salivary composition before radiotherapy.\u003c/p\u003e"},{"header":"6. Conclusion","content":"\u003cp\u003eThis study reports significant alterations in salivary proteins in HNC patients before the commencement of IMRT, characterised by reduced MUC5B and MUC7 concentrations and secretion rates, and increased albumin levels. These findings suggest that saliva composition is altered before radiotherapy, despite the preserved salivary flow rate.\u003c/p\u003e \u003cp\u003eMucin reduction may compromise the oral protection mechanism and contribute to the poor oral health status observed in the HNC patients. These results emphasise the potential benefit of using a salivary compositional assessment before radiotherapy to identify patients at high risk of oral complications and to support the development of targeted preventive strategies.\u003c/p\u003e \u003cp\u003eAlthough the cross-sectional design limits causal inference, this study provides novel insight into salivary alterations in patients with head and neck cancer.\u003c/p\u003e \u003cp\u003eFurther longitudinal and mechanistic studies are required to clarify the clinical significance of these protein changes and their role in the development of oral diseases.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval and consent to participate.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval was granted by the North Scotland Research Ethics Service Committee (REC reference: 16/NS/0116, IRAS Project ID:199100) in October 2016.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eInformed written consent was obtained from all participants before the study commenced, including for data publication. Adverse event reports would follow UK guidelines\u003csup\u003e[51,52]\u003c/sup\u003e; however, there were no adverse events or safety concerns during the study period.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability statement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data were submitted to the Research Data Protection Registration at King’s College London’s research governance, KDPR Registration Reference: DPRF-17/18-6377.\u003c/p\u003e\n\u003cp\u003eResearch data are stored in an institutional repository and will be shared upon request to the corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research leading to these results received funding from Agencia Nacional de Investigación y Desarrollo, Chile, under Grant Agreement No. 6694/201\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e: None\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr Maria Gonzalez A: (\u003cstrong\u003eCorresponding Author\u003c/strong\u003e) This study is a part of a thesis submitted for the degree of Doctor of Philosophy.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDr Sophie S Bozorgi: Experimental methodology, review and editing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNicolas Olivares: analysis, review, and editing.\u003c/p\u003e\n\u003cp\u003eProfessor Guy H Carpenter: Analysis, review, and editing.\u003c/p\u003e\n\u003cp\u003eDr. Mary Burke: Project administration, review and editing, consultant.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eGarrit Koller: analysis, review, and editing\u003c/p\u003e\n\u003cp\u003eProfessor Avijit Banerjee: First supervisor, conceptualisation of the project, review and editing\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e\u003cem\u003eCancer statistics, 2019 | Enhanced Reader\u003c/em\u003e. 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L., Trainor, J., Stevenson, B., Paterson,A., Nicol, A., Keys, W., Donachie, M., Barker, D., Rollings, S., Killough, S., Ban,J., Chatzipantelis, A., Gaitonde, P., Ranka, M., Ali, Z., MacInnes, A., \u0026hellip; Rodriguez,J. M. (2022). Oral prehabilitation for patients with head and neck cancer: getting it right - the Restorative Dentistry-UK consensus on a multidisciplinary approach to oral and dental assessment and planning prior to cancer treatment. \u003cem\u003eBritish Dental Journal\u003c/em\u003e, \u003cem\u003e233\u003c/em\u003e(9), 794\u0026ndash;800. https://doi.org/10.1038/s41415-022-5197-3\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Head and Neck cancer, Saliva, Salivary Proteins, Mucins, caries, radiotherapy","lastPublishedDoi":"10.21203/rs.3.rs-9558012/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9558012/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjectives\u003c/h2\u003e \u003cp\u003e \u003cb\u003eto\u003c/b\u003e examine pre-treatment salivary protein composition and secretion rate of head and neck cancer (HNC) patients and their association with oral health status, specifically clinical caries lesions.\u003c/p\u003e\u003ch2\u003eMaterial and Methods\u003c/h2\u003e \u003cp\u003eA cross-sectional study was conducted, including 40 HNC patients before undergoing intensity-modulated radiotherapy (IMRT) and 28 age- and sex-matched non-cancer controls. (Ethical approval/consent). Unstimulated whole-mouth saliva was collected under standardised conditions. Salivary flow rate, total protein concentration, and secretion rate were assessed. Specific proteins were evaluated(MUC5B, MUC7, ALBUMIN, cystatin S and α-amylase). The dental status was obtained clinically. Differences between groups were analysed using a nonparametric test, and regression models assessed the associations between salivary parameters, cancer status, and the presence of caries.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThere was a significant reduction in MUC5B (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and MUC7 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) concentrations and secretion rates (p\u0026thinsp;=\u0026thinsp;0.0004 and p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001, respectively) in HNC patients. Despite no significant differences in flow rate and total protein secretion rate, albumin concentration (p\u0026thinsp;=\u0026thinsp;0.009) and secretion rate (p\u0026thinsp;=\u0026thinsp;0.02) significantly increased. Clinically, HNC patients had poorer dental status, with fewer healthy teeth and a higher prevalence of carious lesions. In the HNC group, lower MUC7 concentration was associated with the presence of caries lesions. Regression models confirmed that the reduction in mucins was independently associated with cancer status after adjusting for smoking.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eHNC patients exhibit significant alterations in protein composition before IMRT, particularly affecting mucin secretion, while overall gland function remained preserved. These outcomes suggest that salivary dysfunction prior to IMRT may increase susceptibility to oral disease, particularly carious lesions.\u003c/p\u003e\u003ch2\u003eClinical relevance:\u003c/h2\u003e \u003cp\u003epre-radiotherapy assessment of salivary composition may help to identify HNC patients at increased risk of late oral complications and support the development of tailored preventive strategies before the cancer treatment.\u003c/p\u003e","manuscriptTitle":"Altered salivary mucin composition in head and neck cancer patients prior to radiotherapy and its clinical implications for oral health","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-14 12:06:16","doi":"10.21203/rs.3.rs-9558012/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-13T11:17:56+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"220276713774703677440509480433895864977","date":"2026-05-05T09:28:29+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-05T08:43:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-02T13:20:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-29T06:54:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Clinical Oral Investigations","date":"2026-04-28T19:59:47+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1eb6ed89-0586-4315-88b2-c382008071e1","owner":[],"postedDate":"May 14th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-13T11:17:56+00:00","index":13,"fulltext":""},{"type":"reviewerAgreed","content":"220276713774703677440509480433895864977","date":"2026-05-05T09:28:29+00:00","index":7,"fulltext":""},{"type":"reviewersInvited","content":"5","date":"2026-05-05T08:43:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-02T13:20:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-29T06:54:56+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-14T12:06:16+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-14 12:06:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9558012","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9558012","identity":"rs-9558012","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}