Characterization of STRN::ALK Fusions in Oncocytic Thyroid Tumors Reveals Fusion Architecture as a Determinant of Functional ALK Activation

Characterization of STRN::ALK Fusions in Oncocytic Thyroid Tumors Reveals Fusion Architecture as a Determinant of Functional ALK Activation | 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 Characterization of STRN::ALK Fusions in Oncocytic Thyroid Tumors Reveals Fusion Architecture as a Determinant of Functional ALK Activation Debora Mota Dias Thomaz, Thais Biude Mendes, Thaise Nayane Ribeiro Carneiro, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9360178/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Oncocytic thyroid carcinoma (OTC) represents a distinct subtype of thyroid cancer characterized by marked genomic complexity and frequent resistance to radioactive iodine therapy, highlighting the need for refined molecular stratification. Rearrangements involving ALK gene, particularly STRN::ALK fusions, have been described in thyroid neoplasia and may confer susceptibility to targeted inhibition; however, their functional and clinical relevance in oncocytic tumors remains poorly defined. To date, STRN::ALK alterations have not been systematically investigated in this histologic subtype. Here, we provide the first comprehensive evaluation of ALK rearrangements in a cohort of 56 oncocytic thyroid tumors using an integrated multiplatform approach that combines transcript-level detection, genomic validation, protein expression profiling, and in silico structural modeling. STRN::ALK transcripts were identified in 16% of cases and comprised both canonical in-frame fusions and structurally divergent noncanonical variants involving identical exon partner. Although ALK rearrangement was confirmed by FISH in all positive cases, protein expression was strictly confined to OTC harboring canonical in-frame fusions. In contrast, noncanonical variants displayed altered fusion junctions with frameshift configurations predicted to abrogate kinase function. Consistently, structural modeling demonstrated preservation of the catalytic kinase domain in canonical fusions and profound structural disruption in noncanonical variants. These findings establish that fusion architecture, rather than the mere presence of genomic rearrangement, is the key determinant of functional activation. This study expands the molecular landscape of oncocytic thyroid tumors and underscores the importance of integrating molecular and protein-based approaches to accurately identify biologically active fusions, with direct implications for patient selection and therapeutic decision-making. Oncocytic Thyroid Neoplasms Anaplastic Lymphoma Kinase ALK Fusion Proteins Immunohistochemistry Fluorescence In Situ Hybridization Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Thyroid cancer is the most common endocrine malignancy, and its incidence continues to rise worldwide [ 1 ]. Among its histological subtypes, oncocytic thyroid carcinoma (OTC), formerly known as Hürthle cell carcinoma, accounts for 2–5% of cases [ 2 ]. Once considered a subtype of follicular thyroid carcinoma (FTC), OTC is now recognized as a distinct clinicopathological entity, characterized by a unique genomic landscape, biological behavior, and clinical course. This distinction is formally recognized in the current World Health Organization (WHO) classification of thyroid neoplasms [ 2 – 7 ]. Histologically, OTC is defined as an invasive malignant follicular cell neoplasm composed of at least 75% oncocytic cells, lacking the nuclear features of papillary thyroid carcinoma and high-grade characteristics [ 2 – 6 ]. It is distinguished from benign oncocytic thyroid adenoma (OTA) by the presence of capsular and/or vascular invasion, whereas OTA remain encapsulated and lack invasive features [ 1 ]. Notably, the extension of vascular invasion is a key determinant of clinical outcome. Beyond its morphologic features, OTC exhibits a distinctive biological profile frequently associated with chromosomal instability and complex genomic alterations [ 2 – 4 , 6 ]. Clinically, a subset of these tumors demonstrates more aggressive behavior and reduced iodine avidity, thereby limiting the effectiveness of radioactive iodine (RAI) therapy [ 2 , 5 , 6 ]. Collectively, these features highlight the need for deeper molecular characterization with potential diagnostic and therapeutic relevance. In this context, gene fusions involving receptor tyrosine kinases (RTKs) have emerged as clinically relevant oncogenic drivers in thyroid cancer, with direct implications for diagnosis, prognosis, and targeted therapy [ 8 , 9 ]. Among these, fusions involving the anaplastic lymphoma kinase (ALK) gene have been described in papillary, poorly differentiated, and anaplastic thyroid carcinomas [ 10 – 17 ]. In thyroid tumors, STRN is the most frequently reported fusion partner, resulting in the canonical STRN::ALK rearrangement. Tumors harboring in-frame STRN::ALK fusion typically demonstrate ALK protein expression and, notably, clinical responsiveness to ALK-directed therapies, including crizotinib and next-generation inhibitors, underscoring the therapeutic relevance of this alteration [ 10 , 11 , 13 , 18 – 20 ]. Here, we investigated STRN::ALK rearrangements in a large cohort of oncocytic thyroid tumors using an integrated multiplatform approach combining transcript-based detection, genomic validation, protein expression analysis, and in silico structural modeling. This strategy aimed to delineate the biological relevance of these alterations and to establish a framework for their interpretation in diagnostic pathology and therapeutic decision-making. Material and Methods Study Cohort . This study included consecutive formalin-fixed, paraffin-embedded (FFPE) thyroid specimens from patients who underwent thyroidectomy at Hospital São Paulo, Universidade Federal de São Paulo (UNIFESP), between 1995 and 2015, with diagnosis of oncocytic thyroid carcinomas (OTC) and oncocytic thyroid adenomas (OTA). All cases were initially diagnosed at the Department of Pathology, UNIFESP, and subsequently reviewed by an expert thyroid pathologist (ACJP). FFPE blocks were sectioned for molecular analyses. A corresponding hematoxylin-and-eosin-stained slide from deeper levels was reviewed to confirm the diagnosis. The final cohort comprised 27 OTC and 29 OTA cases. The study was conducted in accordance with the Brazilian National Research Ethics Committee (CAAE: 56882116.7.0000.550). Detailed clinicopathological characteristics are summarized in Table 1 . Table 1 Clinical and pathological characteristics of all oncocytic thyroid tumors. Case ID Diagnosis Age at Diagnosis (years) Gender Tumor size (cm) Capsular invasion Vascular invasion Extent of Vascular Invasion pTNM (AJCC 8th Edition) 1 OTC 62 F 2 N Y Mi pT2 2 OTC 51 M 2.2 Y Y Mi pT2 3 OTC 55 F 0.3 N Y Wi pT1a 4* OTC 75 F 2.6 Y Y Wi pT2 5* OTC 58 F 1.4 Y N NA pT1b 6 OTC 47 F 1.8 N Y Mi pT1b 7* OTC 48 F 1.8 N Y Mi pT1b 8 OTC 86 F 5.5 N Y Mi pT3 9* OTC 59 F 2 Y Y Mi pT2 10* OTC 28 F 4 N Y Mi pT2 11* OTC 31 F 2.5 N Y Mi pT2 12* OTC 71 F 1.2 Y N NA pT1b 13 OTC 58 F 4 Y N NA pT3 14 OTC 53 M 4 Y Y Mi pT3 15 OTC 44 M 4.5 N Y Wi pT3 16 OTC 40 F 2 Y Y Wi pT2 17 OTC 37 F 3 Y Y Mi pT2 18 OTC 53 F 2.5 Y N NA pT2 19 OTC 65 F 4.5 Y Y Mi pT3 20 OTC 82 F 10 Y Y Mi pT4a 21 OTC 64 F 2.1 Y Y Wi pT2 22 OTC 51 M 2.1 N Y Mi pT2 23 OTC 40 F 0.5 Y Y Wi pT1a 24 OTC 72 M 3.2 N Y Wi pT3 25 OTC 54 F 3 Y Y Mi pT2 26 OTC 68 F 10 Y Y Mi pT3 27 OTC 59 F 0.5 Y Y Mi pT1a 28* OTA 67 F 3 N N NA NA 29 OTA 51 M 2.2 N N NA NA 30 OTA 48 F 1 N N NA NA 31 OTA 63 F 1.8 N N NA NA 32 OTA 42 F 4 N N NA NA 33 OTA 39 F 1 N N NA NA 34 OTA 44 F 4 N N NA NA 35 OTA NR F 3.5 N N NA NA 36 OTA 27 F 2 N N NA NA 37 OTA NR F 4 N N NA NA 38 OTA 53 M 2 N N NA NA 39 OTA 41 F 2.5 N N NA NA 40* OTA 50 F 4 N N NA NA 41 OTA 68 F 1.7 N N NA NA 42 OTA NR F 3.5 N N NA NA 43 OTA 79 F 12 N N NA NA 44 OTA 62 F 2.2 N N NA NA 45 OTA 43 F 2 N N NA NA 46 OTA 66 F 3.5 N N NA NA 47 OTA 73 F 4.5 N N NA NA 48 OTA 35 F 2.5 N N NA NA 49 OTA 53 F 6.5 N N NA NA 50 OTA 64 F 0.8 N N NA NA 51 OTA 29 F 1.8 N N NA NA 52 OTA 64 M 1.8 N N NA NA 53 OTA 23 F 5.5 N N NA NA 54 OTA 66 F 2.1 N N NA NA 55 OTA 51 F 0.7 N N NA NA 56 OTA 27 F 2.5 N N NA NA * STRN::ALK fusion positive cases; OTC: Oncocytic Thyroid Carcinoma; OTA: Oncocytic Thyroid Adenoma; F: Female; M: Male; NR: Not Reported; Y: Yes; N: No; Mi: Minimally invasive; Wi: Widely invasive; NA: Not Aplicable. STRN::ALK Fusion Transcript Screening and Characterization. Total RNA was extracted from three 10-µm FFPE sections using the RecoverAll™ Total Nucleic Acid Isolation Kit (Applied Biosystems, Waltham, MA, USA), following the manufacturer’s protocol. RNA quantity and purity were assessed using a NanoDrop ND-2000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). For cDNA synthesis, 500 ng of total RNA was treated with DNase and reverse-transcribed using the SuperScript™ III First-Strand Synthesis System (Invitrogen, Waltham, MA, USA) with a combination of oligo(dT)20 primers and random hexamers, according to the manufacturer’s instructions. cDNA integrity was evaluated by amplification of the housekeeping gene RPS8 , as previously described [ 21 ]. Screening for STRN::ALK fusion transcripts was performed by conventional PCR using primers targeting STRN exon 3 (forward: 5’-CGGGACAGAATTGAATCAGG = 3’) and ALK exon 20 (reverse: 5’-CAAGCCATGCAGATGGAGC-3’). PCR amplifications were carried out in a final volume of 50 µL containing 2 µL of cDNA, 0.5 U of Platinum™ Taq DNA Polymerase, 1× PCR buffer, 1.5 mM MgCl2, 200 µM dNTPs, and 5 pmol of each primer (Invitrogen). Cycling conditions included an initial denaturation at 95°C for 5 min, followed by 40 cycles of 95°C for 30 s, 58°C for 30 s, and 72°C for 30 s, with a final extension at 72°C for 5 min. The expected amplicon size was 94 bp. PCR products were resolved on 2.5% agarose gels and visualized using a Gel Doc™ EZ Imaging System (Bio-Rad Laboratories, Hercules, CA, USA). To confirm fusion transcripts and define breakpoint sequences, PCR products were cloned into the pCR™2.1-TOPO® vector using the TOPO TA Cloning Kit (Thermo Fisher Scientific), according to the manufacturer’s instructions. For each case, three independent PCR amplifications were performed and cloned separately to ensure reproducibility of the detected fusion transcripts. One bacterial colony from each independent cloning reaction was selected, expanded, and subjected to Sanger sequencing using the BigDye™ Terminator Cycle Sequencing Kit (Thermo Fisher Scientific), as previously described [ 22 ]. ALK Break-Apart Fluorescence in situ hybridization (FISH). All PCR-positive cases were further evaluated for ALK rearrangements using a dual-color break-apart FISH assay. Analyses were performed on 3-µm FFPE sections using locus-specific bacterial artificial chromosome (BAC) probes targeting ALK (2p23.2; RP11-418E15 and RP11-203K5; Invitrogen), labeled with Spectrum Green and Spectrum Red by nick translation (Abbott Molecular, Chicago, IL, USA), according to the manufacturer’s instructions. Sections were deparaffinized, rehydrated, and subjected to pretreatment, followed by denaturation at 73°C for 5 min and overnight hybridization at 37°C in a humidified chamber. Post-hybridization washes included stringent washes at 65°C and non-stringent washes at room temperature. Slides were counterstained with ProLong Gold Antifade Mountant containing DAPI (Invitrogen). Fluorescence signals were analyzed using a Zeiss fluorescence microscope (Zeiss, Oberkochen, Germany) equipped with ISIS image analysis software (MetaSystems, Altlussheim, Germany). For each case, 100 intact, non-overlapping interphase nuclei were evaluated. Normal nuclei displayed two fused (yellow) signals, whereas rearranged nuclei exhibited one fused signal and separate red and green signals. Cases were classified as ALK-rearranged when > 10% of nuclei demonstrated split signals, according to thresholds established using normal thyroid tissue controls, as previously described [ 23 ]. ALK Immunohistochemistry (IHC). ALK protein expression was evaluated by immunohistochemistry as a surrogate marker for kinase fusion-driven overexpression of chimeric ALK proteins [ 24 ]. Analyses were performed on 3-µm sections of formalin-fixed, paraffin-embedded (FFPE) tissue. Following deparaffinization and rehydration, endogenous peroxidase activity was quenched with 3% hydrogen peroxide for 30 min. Antigen retrieval was carried out in Tris-EDTA buffer (pH 9.0) using a pressure cooker. Non-specific binding was blocked with 5% goat serum in TBST for 1 hour at room temperature. Sections were incubated overnight at 4°C with a rabbit monoclonal anti-ALK antibody (clone D5F3; dilution 1:50; Cell Signaling Technology, Danvers, MA, USA). Immunodetection was performed using the EnVision Dual Link system (Agilent Technologies, Santa Clara, CA, USA), followed by hematoxylin counterstaining. Appropriate positive and negative controls were included in each run, consisting of commercially available formalin-fixed, paraffin-embedded cell line pellets provided by Cell Signaling Technology, with known ALK expression status, and processed in parallel with study samples to ensure assay specificity and optimal staining performance. ALK staining intensity and subcellular distribution were independently assessed by light microscopy. Samples were considered IHC positive if tumor-specific staining of any intensity was present in ≥ 10% of the tumor cell. In silico structural and functional analysis . Predicted protein sequences derived from STRN::ALK fusion transcripts were generated using the ExPASy Translate Tool [ 25 ]. Open reading frames were selected based on the first in-frame methionine and minimal instability index, prioritizing predicted protein stability. Physicochemical properties, including protein length, molecular weight, theoretical isoelectric point, amino acid composition, grand average of hydropathicity (GRAVY), aliphatic index, and estimated half-life, were computed to support functional inference. Three-dimensional structural models were generated using the Phyre2 platform [ 26 ] based on homology modeling. Predicted structures were compared with canonical STRN::ALK fusion proteins to assess domain architecture, integrity of the ALK kinase domain, and potential structural consequences for dimerization and ligand-independent activation. These analyses were used to infer the functional relevance of identified fusion variants. Statistical analysis. Statistical analyses were performed using RStudio and GraphPad Prism 10. Categorical variables (e.g., sex) were compared using Pearson’s Chi-square test or Fisher’s exact test, as appropriate. Continuous variables (e.g., age and tumor size) were analyzed using Student’s t -test or one-way ANOVA, depending on the number of groups. When applicable, the Bonferroni correction was applied to adjust for multiple comparisons. A p -value < 0.05 was considered statistically significant. Results Detection of Canonical and Structurally Divergent STRN::ALK Fusions in Oncocytic Thyroid Tumors RT-PCR screening identified STRN::ALK transcripts in 9 of 56 cases of oncocytic thyroid tumors (16%). Two OTCs yielded an amplicon of approximately 100 bp, consistent with the expected size of the canonical in-frame STRN::ALK fusion. In contrast, the remaining seven positive tumors (five OTCs and two OTAs) exhibited a shorter amplicon of approximately 50 bp (Fig. 1 A). Cloning and Sanger sequencing defined the fusion's architecture. The 94 bp amplicons corresponded to the canonical in-frame fusion between STRN exon 3 and ALK exon 20 (Fig. 1 B, C). In contrast, all shorter amplicons involved the same exon pairing but exhibited structurally altered junctions, characterized by internal deletions and breakpoint shifts that disrupt the reading frame (Fig. 1 D, E). Based on junction structure, STRN::ALK -positive tumors segregated into canonical in-frame fusions (cases 5 and 10) and noncanonical out-of-frame variants. The latter comprised two recurrent subclasses: Type I variants, defined by frameshifted junctions with altered codon phasing (cases 4, 9, 11, and 12), and Type II variants, in which the frameshift introduces a premature termination codon (cases 7, 28, and 40) (Fig. 1 F and Table 2 ). Table 2 Summary of molecular and immunohistochemical findings in STRN::ALK -positive tumors. Case ID Diagnosis RT-PCR product size (bp) Fusion type ALK-rearranged nuclei (%) ALK IHC Predicted kinase activity 4 OTC 50 Out-of-frame Type I 15 Negative Impaired 5 OTC 94 Canonical 58 Positive Full 7 OTC 50 Out-of-frame Type II 13 Negative Inactive 9 OTC 50 Out-of-frame Type I 12 Negative Impaired 10 OTC 94 Canonical 23 Positive Full 11 OTC 50 Out-of-frame Type I 15 Negative Impaired 12 OTC 50 Out-of-frame Type I 12 Negative Impaired 28 OTA 50 Out-of-frame Type II 23 Negative Inactive 40 OTA 50 Out-of-frame Type II 35 Negative Inactive OTC: Oncocytic Thyroid Carcinoma; OTA: Oncocytic Thyroid Adenoma. Genomic Validation Confirms ALK Rearrangement Across Canonical and Noncanonical Variants Break-apart FISH confirmed ALK rearrangement in all nine RT-PCR-positive tumors, with split signals detected in 12–58% of nuclei (Fig. 2 A). Rearrangement signals were observed in both canonical in-frame cases (Case 5, Fig. 2 B; Case 10, Supplementary Fig. 1) and out-of-frame variants (Case 4, Fig. 2 C; cases 7, 9, 11, 12, 28, and 40, Supplementary Fig. 1). Fusion Architecture Determines ALK Protein Expression Diffuse cytoplasmic ALK staining was detected exclusively in OTCs harboring canonical in-frame STRN::ALK fusions (Case 5, Fig. 3 A; Case 10, Supplementary Fig. 2). In contrast, all tumors carrying out-of-frame variants lacked detectable ALK expression (Case 4, Fig. 3 B; Cases 7, 9, 11, 12, 28, and 40, Supplementary Fig. 2). Matched adjacent normal thyroid tissue was consistently negative. Structural Modeling Reveals Loss of Kinase Integrity in Out-of-frame Variants Homology-based modeling demonstrated that the canonical STRN::ALK fusion preserves the structural integrity of the ALK kinase domain, supporting a catalytically competent configuration (Fig. 4 A). In contrast, all out-of-frame variants exhibited marked structural disruption and segregated into two recurrent architectures. Type I variants (Cases 4, 9, 11, and 12) were predicted to encode proteins of approximately 685 amino acids with internal deletions disrupting kinase domain continuity, retaining only a limited portion of the ALK-derived sequences exhibiting increased structural disorder. Type II variants (Cases 7, 28, and 40) generated severely truncated proteins of approximately 145 amino acids due to premature termination, aligning exclusively to STRN -derived regions and lacking ALK coding sequence (Fig. 4 B; Table 2 ). Structural similarity analysis corroborated these observations. Type I variants displayed weak similarity to canonical STRN::ALK , whereas Type II variants exhibited minimal structural correspondence, consistent with the absence of ALK-derived domains. Accordingly, structure-based functional inference predicted preserved kinase activity for canonical fusions, impaired activity in Type I variants, and complete loss of kinase function in Type II variants (Fig. 4 C). Additional physicochemical parameters are provided in Supplementary Table 1. Canonical STRN::ALK fusions Are Restricted to Malignant Oncocytic Tumors Clinicopathological features of STRN::ALK -positive tumors are summarized in Table 1 . Canonical in-frame fusions were identified exclusively in OTC, supporting their restriction to malignant oncocytic neoplasms within this cohort. No significant differences in baseline clinicopathological features, including patient age, tumor size, or other indicators of tumor aggressiveness, were observed between tumors harboring canonical fusions and those with out-of-frame variants. However, these analyses were limited by sample size and were not powered to detect subtle differences. Discussion To our knowledge, this is the first study to identify STRN::ALK fusions in oncocytic thyroid carcinoma and to demonstrate that these rearrangements comprise structurally and functionally distinct entities. Using an integrated multiplatform approach, we show that although ALK rearrangement is consistently detectable at the genomic level, only canonical in-frame fusions result in detectable ALK protein expression. These findings demonstrate that fusion architecture, rather than the mere presence of a genomic rearrangement, is the key determinant of functional activation. Most STRN::ALK -positive tumors in this cohort harbored noncanonical, out-of-frame fusion transcripts involving the same exon pairing ( STRN exon 3 and ALK exon 20) but disrupted by internal deletions and shifted breakpoints. While consistently detected by break-apart FISH, these variants do not preserve the reading frame. Structural modeling predicted that such alterations result in partial or complete loss of the ALK kinase domain, in contrast to canonical fusions, which retain structural integrity consistent with oncogenic activation. These structural differences translated into clear protein-level consequences. ALK expression by immunohistochemistry was restricted to tumors harboring canonical in-frame fusions, whereas all out-of-frame variants were immunonegative, despite confirmed genomic rearrangement. In this context, ALK IHC appears to identify biologically active fusions rather than simply reflecting rearrangement status. These findings provide a mechanistic explanation for potential discordance between FISH and IHC results and underscore a critical diagnostic limitation. Such discrepancies have been reported in several tumor types, including thyroid [ 13 , 17 , 27 , 28 ] and may be particularly relevant in oncocytic thyroid neoplasms, which are characterized by mitochondrial accumulation and widespread genomic instability, potentially favoring the emergence of nonfunctional rearrangements [ 3 , 4 ]. The observation that canonical STRN::ALK fusions occur in oncocytic thyroid carcinomas, whereas noncanonical variants were observed in both carcinomas and adenomas, further supports the notion that only structurally intact fusions contribute to tumorigenesis. Noncanonical variants may instead represent passenger events arising from genomic instability, consistent with their predicted loss of kinase function. These findings also have potential clinical implications. As the therapeutic response to ALK inhibitors depends on the presence of a functional kinase, accurate identification of biologically active fusions is essential. In this context, the integration of molecular and protein-based assays may improve patient selection, particularly in oncocytic thyroid carcinomas, which often exhibit limited responsiveness to conventional therapies [ 3 – 5 ]. Consistent with this, although uncommon, ALK rearrangements have been described in papillary thyroid carcinoma and extend across the spectrum of aggressive thyroid malignancies, including poorly differentiated and anaplastic thyroid carcinomas [ 10 – 17 , 24 , 29 ]. This study has limitations. Functional activity was inferred from structural modeling and protein expression rather than directly assessed in experimental systems. In addition, the modest sample size limits clinicopathological correlations. Further studies are warranted to determine the prevalence and significance of similar noncanonical fusions in broader thyroid tumor cohorts and to validate their biological behavior In summary, STRN::ALK rearrangements in oncocytic thyroid tumors comprise two biologically distinct entities: rare canonical in-frame fusions that preserve kinase function and more frequent noncanonical variants that are structurally disrupted and likely nonfunctional. These findings underscore the importance of integrative molecular assessment and caution against associating genomic rearrangement with functional activation, particularly when selecting patients for targeted therapies. Together, they highlight the need for combined molecular and protein-based approaches when evaluating ALK rearrangements, especially in oncocytic thyroid tumors, where genomic instability may give rise to nonfunctional alterations. Declarations Code availability Not applicable. Ethical approval and consent to participate This study was approved by the Brazilian National Research Ethics Committee (CAAE: 56882116.7.0000.550). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The requirement for informed consent was waived due to the retrospective nature of the study. Consent to Participate Informed consent was waived by the institutional review board because of the retrospective nature of this study, which used anonymous clinical data. Consent for Publication All authors approved for the publication of this paper Competing Interests The authors declare that they have no competing interests. Funding This study was supported by research grants from the São Paulo Research Foundation (FAPESP; grant numbers 2014/06570-6 and 2022/09713-9) and National Council for Scientific and Technological Development (CNPq; grant number 406952/2022-1). D.M.D.T., T.B.M., and L.S. received fellowship support from FAPESP (grant numbers 2020/06594-3, 17/06487-0, and 18/09911-0). T.N.R.C. received a fellowship from the CNPq. J.M.C. was awarded a Research Productivity Scholarship from CNPq (grant number 304534/2018-8). We also acknowledge financial support from CAPES. Author Contribution All authors contributed to the study conception and design. Data curation, formal analysis, investigation, and visualization were performed by Debora Mota Dias Thomaz. Methodology was developed by Debora Mota Dias Thomaz, Thais Biude Mendes, Thaise Nayane Ribeiro Carneiro, and Luiza Sisdelli. Validation was performed by Debora Mota Dias Thomaz and Ana Carolina de Jesus Paniza. Resources, funding acquisition, and supervision were provided by Janete Maria Cerutti. Project administration was carried out by Debora Mota Dias Thomaz and Janete Maria Cerutti. The first draft of the manuscript was written by Debora Mota Dias Thomaz, and all authors (Thais Biude Mendes, Thaise Nayane Ribeiro Carneiro, Luiza Sisdelli, Ana Carolina de Jesus Paniza, André Uchimura Bastos, and Janete Maria Cerutti) contributed to the review and editing of the manuscript. All authors read and approved the final manuscript. Data Availability All data supporting the findings of this study are available within the paper and its Supplementary Information. References Vaio F, Moliterni C, Mardente S, Misasi R, Mari E (2026) State of the Art on Thyroid Cancer Biology and Oncology. Biomedicines 14:168. https://doi.org/10.3390/biomedicines14010168 Finnegan EA, Ganly I (2026) Approach to the Patient: Oncocytic Thyroid Cancer. 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Cancer 115:972–980. https://doi.org/10.1002/cncr.24118 Sisdelli L, Cordioli MICV, Vaisman F, Moraes L, Colozza-Gama GA, Alves Jr PAG, Araújo Jr ML, Alves MTS, Monte O, Longui CA (2019) AGK‐BRAF is associated with distant metastasis and younger age in pediatric papillary thyroid carcinoma. Pediatr Blood Cancer 66:e27707. https://doi.org/10.1002/pbc.27707 Rivera JP, Hang J-F (2025) Next-generation immunohistochemistry in thyroid neoplasm: a practical review on the applications in diagnosis and molecular classification. Endocr Pathol 36:8. https://doi.org/10.1007/s12022-025-09851-6 Artimo P, Jonnalagedda M, Arnold K, Baratin D, Csardi G, De Castro E, Duvaud S, Flegel V, Fortier A, Gasteiger E (2012) ExPASy: SIB bioinformatics resource portal. Nucleic Acids Res 40:W597–W603. https://doi.org/10.1093/nar/gks400 Kelley LA, Mezulis S, Yates CM, Wass MN, Sternberg MJE (2015) The Phyre2 web portal for protein modeling, prediction and analysis. Nat Protoc 10:845–858. https://doi.org/10.1038/nprot.2015.053 Lin C, Shi X, Yang S, Zhao J, He Q, Jin Y, Yu X (2019) Comparison of ALK detection by FISH, IHC and NGS to predict benefit from crizotinib in advanced non-small-cell lung cancer. Lung Cancer 131:62–68. https://doi.org/10.1016/j.lungcan.2019.03.018 Park G, Kim TH, Lee H-O, Lim JA, Won J-K, Min HS, Lee KE, Park DJ, Park YJ, Park W-Y (2015) Standard immunohistochemistry efficiently screens for anaplastic lymphoma kinase rearrangements in differentiated thyroid cancer. Endocr Relat Cancer 22:55–63. https://doi.org/10.1530/erc-14-0467 Shih K-P, Lee Y-C, Tsai J-J, Lin S-H, Liu C-Y, Li W-S, Li C-F, Hang J-F (2024) Clinicopathologic features and cytologic correlation of ALK-rearranged papillary thyroid carcinoma: a series of eight cases. Endocr Pathol 35:134–146. https://doi.org/10.1007/s12022-024-09808-1 Additional Declarations No competing interests reported. Supplementary Files SupplementaryMaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 27 Apr, 2026 Reviews received at journal 27 Apr, 2026 Reviews received at journal 25 Apr, 2026 Reviewers agreed at journal 16 Apr, 2026 Reviewers agreed at journal 16 Apr, 2026 Reviewers invited by journal 15 Apr, 2026 Editor assigned by journal 09 Apr, 2026 Submission checks completed at journal 09 Apr, 2026 First submitted to journal 08 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9360178","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":624402944,"identity":"57e5a827-1bae-49ef-9211-d845c4a9749c","order_by":0,"name":"Debora Mota Dias Thomaz","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"Debora","middleName":"Mota Dias","lastName":"Thomaz","suffix":""},{"id":624402945,"identity":"aa022d28-5b6a-4cad-90dd-c115ee3621f0","order_by":1,"name":"Thais Biude Mendes","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"Thais","middleName":"Biude","lastName":"Mendes","suffix":""},{"id":624402946,"identity":"ca602f67-c037-4a7b-9cd4-8bdd6fddda2c","order_by":2,"name":"Thaise Nayane Ribeiro Carneiro","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"Thaise","middleName":"Nayane Ribeiro","lastName":"Carneiro","suffix":""},{"id":624402947,"identity":"261984bc-0cc4-411e-bfe7-6f6bf3f1ddfa","order_by":3,"name":"Luiza Sisdelli","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"Luiza","middleName":"","lastName":"Sisdelli","suffix":""},{"id":624402948,"identity":"0c5df6fe-f978-474b-ac1a-618feb98c09f","order_by":4,"name":"Ana Carolina Jesus Paniza","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"Ana","middleName":"Carolina Jesus","lastName":"Paniza","suffix":""},{"id":624402949,"identity":"8b849f70-c87b-45da-b426-5a7b864243b5","order_by":5,"name":"André Uchimura Bastos","email":"","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":false,"prefix":"","firstName":"André","middleName":"Uchimura","lastName":"Bastos","suffix":""},{"id":624402950,"identity":"fd927476-451b-449c-bfe6-37b670a6b75a","order_by":6,"name":"Janete Maria Cerutti","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYBACxgYog40dyEqwATF5iNJiIMHGcwCoJY0ILVBgIMEgkQCkidHC3MD88HFl2586Psk3Zg8eJNjYmzPwHvuA32FsxoZn24AOk84xN0hISEvc2cCXPAO/Fh42yUaIFjOJxB+HEwwO8BjjdRhQC/tPsBbJM2YSCQn/7YnRwsYI1iLBA9JygHEDQS3NbMaSDeeMJdt40sqAWpITdzbzJePVYtje/PBjQ5kcv3z74W2SPxLs7M3Zew/j19KMLmLAjFcDA4M8hogBAR2jYBSMglEw8gAA5lM8sGPhLt8AAAAASUVORK5CYII=","orcid":"","institution":"Universidade Federal de São Paulo - Escola Paulista de Medicina","correspondingAuthor":true,"prefix":"","firstName":"Janete","middleName":"Maria","lastName":"Cerutti","suffix":""}],"badges":[],"createdAt":"2026-04-08 18:09:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9360178/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9360178/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107619797,"identity":"1ee02688-aac9-4639-ad3c-ec08fc9266aa","added_by":"auto","created_at":"2026-04-23 09:32:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":307096,"visible":true,"origin":"","legend":"\u003cp\u003eDetection and structural characterization of \u003cem\u003eSTRN::ALK\u003c/em\u003e transcripts in oncocytic thyroid tumors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003eRT-PCR screening for \u003cem\u003eSTRN::ALK\u003c/em\u003e transcripts identifies two tumors with the expected 94 bp amplicon corresponding to the canonical fusion, whereas the remaining positive cases exhibit a shorter 50 bp amplicon. M, molecular weight; N, negative control.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(B-C) \u003c/strong\u003eSanger sequencing electropherograms confirming the canonical in-frame fusion between \u003cem\u003eSTRN \u003c/em\u003eexon 3 and \u003cem\u003eALK \u003c/em\u003eexon 20.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(D-E) \u003c/strong\u003eRepresentative electropherograms of noncanonical junctions corresponding to Type I and Type II variants observed in tumors with shorter amplicons, demonstrating altered breakpoint usage.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(F)\u003c/strong\u003e Schematic representation of the canonical \u003cem\u003eSTRN::ALK \u003c/em\u003efusion alongside with two recurrent classes of out-of-frame variants identified in this study. Type I variants are defined by internal deletions leading to frameshifted junctions, whereas Type II variants arise from shifted breakpoints that introduce premature termination codons.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/dc70d44c52ae5fa754ed3fdf.png"},{"id":107619799,"identity":"d07de1e3-46c9-40df-8949-f6c222e60331","added_by":"auto","created_at":"2026-04-23 09:32:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":265792,"visible":true,"origin":"","legend":"\u003cp\u003eFluorescence in situ hybridization (FISH) analysis of ALK rearrangements in \u003cem\u003eSTRN::ALK\u003c/em\u003e-positive oncocytic thyroid tumors\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003ePercentage of nuclei showing \u003cem\u003eALK\u003c/em\u003e split signals in the nine RT-PCR positive tumors (100 nuclei counted per case).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(B) \u003c/strong\u003eRepresentative FISH image from Case 5 harboring the canonical \u003cem\u003eSTRN::ALK \u003c/em\u003efusion, showing cells with split green and red signals indicating \u003cem\u003eALK\u003c/em\u003erearrangement and fused yellow signals corresponding to normal alleles.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(C) \u003c/strong\u003eRepresentative FISH image from Case 4 harboring an out-of-frame fusion, showing the same rearranged signal pattern.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/439f403a207f3e9dcbf3d62b.png"},{"id":107619801,"identity":"a7595eb9-7bfa-476a-8f92-aa40fe1484ff","added_by":"auto","created_at":"2026-04-23 09:32:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":744054,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eALK immunohistochemistry in oncocytic thyroid tumors (original magnification ×400).\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTop: Case 5, harboring the canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion, shows diffuse cytoplasmic ALK expression in tumor cells, with absent staining in adjacent non-neoplastic thyroid tissue.\u003c/p\u003e\n\u003cp\u003eBottom: Case 4, harboring an out-of-frame variant, shows complete absence of ALK immunoreactivity despite confirmed \u003cem\u003eALK\u003c/em\u003e rearrangement by FISH.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/d1188aa580e09dfebd6e0c08.png"},{"id":107619800,"identity":"be4ac927-488d-4cab-a83d-b5ee5eec6c0a","added_by":"auto","created_at":"2026-04-23 09:32:16","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":347612,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStructural consequences of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eSTRN::ALK\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e fusion variants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003eSchematic comparison of canonical, Type I, and Type II fusion architectures, highlighting differences in the preservation of key ALK functional domains.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(B) \u003c/strong\u003ePredicted three-dimensional models illustrating the progressive structural disruption from canonical to Type I and Type II variants.\u003c/p\u003e\n\u003cp\u003e(\u003cstrong\u003eC) \u003c/strong\u003eIntegrated summary of inferred kinase activity across fusion classes based on structural modeling analyses.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/dcd0013211cd09aa461d1bdd.png"},{"id":107710197,"identity":"466ce2c6-46ff-4cc4-b408-de8577895ec6","added_by":"auto","created_at":"2026-04-24 09:39:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2273617,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/5c6ebf54-7509-487a-85c5-7f0b7a04a77c.pdf"},{"id":107706807,"identity":"f8b2c114-972e-4205-a877-aec9299a6df3","added_by":"auto","created_at":"2026-04-24 09:18:47","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":698947,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-9360178/v1/ec2127ca8ad2daa641a69950.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Characterization of STRN::ALK Fusions in Oncocytic Thyroid Tumors Reveals Fusion Architecture as a Determinant of Functional ALK Activation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThyroid cancer is the most common endocrine malignancy, and its incidence continues to rise worldwide [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Among its histological subtypes, oncocytic thyroid carcinoma (OTC), formerly known as H\u0026uuml;rthle cell carcinoma, accounts for 2\u0026ndash;5% of cases [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Once considered a subtype of follicular thyroid carcinoma (FTC), OTC is now recognized as a distinct clinicopathological entity, characterized by a unique genomic landscape, biological behavior, and clinical course. This distinction is formally recognized in the current World Health Organization (WHO) classification of thyroid neoplasms [\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHistologically, OTC is defined as an invasive malignant follicular cell neoplasm composed of at least 75% oncocytic cells, lacking the nuclear features of papillary thyroid carcinoma and high-grade characteristics [\u003cspan additionalcitationids=\"CR3 CR4 CR5\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. It is distinguished from benign oncocytic thyroid adenoma (OTA) by the presence of capsular and/or vascular invasion, whereas OTA remain encapsulated and lack invasive features [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Notably, the extension of vascular invasion is a key determinant of clinical outcome.\u003c/p\u003e \u003cp\u003eBeyond its morphologic features, OTC exhibits a distinctive biological profile frequently associated with chromosomal instability and complex genomic alterations [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Clinically, a subset of these tumors demonstrates more aggressive behavior and reduced iodine avidity, thereby limiting the effectiveness of radioactive iodine (RAI) therapy [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Collectively, these features highlight the need for deeper molecular characterization with potential diagnostic and therapeutic relevance.\u003c/p\u003e \u003cp\u003eIn this context, gene fusions involving receptor tyrosine kinases (RTKs) have emerged as clinically relevant oncogenic drivers in thyroid cancer, with direct implications for diagnosis, prognosis, and targeted therapy [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Among these, fusions involving the anaplastic lymphoma kinase (ALK) gene have been described in papillary, poorly differentiated, and anaplastic thyroid carcinomas [\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In thyroid tumors, \u003cem\u003eSTRN\u003c/em\u003e is the most frequently reported fusion partner, resulting in the canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e rearrangement. Tumors harboring in-frame \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion typically demonstrate ALK protein expression and, notably, clinical responsiveness to ALK-directed therapies, including crizotinib and next-generation inhibitors, underscoring the therapeutic relevance of this alteration [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHere, we investigated \u003cem\u003eSTRN::ALK\u003c/em\u003e rearrangements in a large cohort of oncocytic thyroid tumors using an integrated multiplatform approach combining transcript-based detection, genomic validation, protein expression analysis, and \u003cem\u003ein silico\u003c/em\u003e structural modeling. This strategy aimed to delineate the biological relevance of these alterations and to establish a framework for their interpretation in diagnostic pathology and therapeutic decision-making.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003e \u003cb\u003eStudy Cohort\u003c/b\u003e. This study included consecutive formalin-fixed, paraffin-embedded (FFPE) thyroid specimens from patients who underwent thyroidectomy at Hospital S\u0026atilde;o Paulo, Universidade Federal de S\u0026atilde;o Paulo (UNIFESP), between 1995 and 2015, with diagnosis of oncocytic thyroid carcinomas (OTC) and oncocytic thyroid adenomas (OTA). All cases were initially diagnosed at the Department of Pathology, UNIFESP, and subsequently reviewed by an expert thyroid pathologist (ACJP). FFPE blocks were sectioned for molecular analyses. A corresponding hematoxylin-and-eosin-stained slide from deeper levels was reviewed to confirm the diagnosis. The final cohort comprised 27 OTC and 29 OTA cases. The study was conducted in accordance with the Brazilian National Research Ethics Committee (CAAE: 56882116.7.0000.550). Detailed clinicopathological characteristics are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\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\u003eClinical and pathological characteristics of all oncocytic thyroid tumors.\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\u003eCase ID\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiagnosis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAge at Diagnosis (years)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTumor size (cm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCapsular invasion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eVascular invasion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eExtent of Vascular Invasion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003epTNM (AJCC 8th Edition)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eWi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT1a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eWi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT1b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT1b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT1b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT1b\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eWi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e 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align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e 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colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eWi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.1\u003c/p\u003e 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align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003epT3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e 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colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.2\u003c/p\u003e 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align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e 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align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e 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align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e 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align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003e*\u003cem\u003eSTRN::ALK\u003c/em\u003e fusion positive cases; OTC: Oncocytic Thyroid Carcinoma; OTA: Oncocytic Thyroid Adenoma; F: Female; M: Male; NR: Not Reported; Y: Yes; N: No; Mi: Minimally invasive; Wi: Widely invasive; NA: Not Aplicable.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eSTRN::ALK\u003c/b\u003e \u003cb\u003eFusion Transcript Screening and Characterization.\u003c/b\u003e Total RNA was extracted from three 10-\u0026micro;m FFPE sections using the RecoverAll\u0026trade; Total Nucleic Acid Isolation Kit (Applied Biosystems, Waltham, MA, USA), following the manufacturer\u0026rsquo;s protocol. RNA quantity and purity were assessed using a NanoDrop ND-2000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). For cDNA synthesis, 500 ng of total RNA was treated with DNase and reverse-transcribed using the SuperScript\u0026trade; III First-Strand Synthesis System (Invitrogen, Waltham, MA, USA) with a combination of oligo(dT)20 primers and random hexamers, according to the manufacturer\u0026rsquo;s instructions. cDNA integrity was evaluated by amplification of the housekeeping gene \u003cem\u003eRPS8\u003c/em\u003e, as previously described [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eScreening for \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion transcripts was performed by conventional PCR using primers targeting \u003cem\u003eSTRN\u003c/em\u003e exon 3 (forward: 5\u0026rsquo;-CGGGACAGAATTGAATCAGG\u0026thinsp;=\u0026thinsp;3\u0026rsquo;) and \u003cem\u003eALK\u003c/em\u003e exon 20 (reverse: 5\u0026rsquo;-CAAGCCATGCAGATGGAGC-3\u0026rsquo;). PCR amplifications were carried out in a final volume of 50 \u0026micro;L containing 2 \u0026micro;L of cDNA, 0.5 U of Platinum\u0026trade; Taq DNA Polymerase, 1\u0026times; PCR buffer, 1.5 mM MgCl2, 200 \u0026micro;M dNTPs, and 5 pmol of each primer (Invitrogen). Cycling conditions included an initial denaturation at 95\u0026deg;C for 5 min, followed by 40 cycles of 95\u0026deg;C for 30 s, 58\u0026deg;C for 30 s, and 72\u0026deg;C for 30 s, with a final extension at 72\u0026deg;C for 5 min. The expected amplicon size was 94 bp. PCR products were resolved on 2.5% agarose gels and visualized using a Gel Doc\u0026trade; EZ Imaging System (Bio-Rad Laboratories, Hercules, CA, USA).\u003c/p\u003e \u003cp\u003eTo confirm fusion transcripts and define breakpoint sequences, PCR products were cloned into the pCR\u0026trade;2.1-TOPO\u0026reg; vector using the TOPO TA Cloning Kit (Thermo Fisher Scientific), according to the manufacturer\u0026rsquo;s instructions. For each case, three independent PCR amplifications were performed and cloned separately to ensure reproducibility of the detected fusion transcripts. One bacterial colony from each independent cloning reaction was selected, expanded, and subjected to Sanger sequencing using the BigDye\u0026trade; Terminator Cycle Sequencing Kit (Thermo Fisher Scientific), as previously described [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eALK\u003c/b\u003e \u003cb\u003eBreak-Apart Fluorescence\u003c/b\u003e \u003cb\u003ein situ\u003c/b\u003e \u003cb\u003ehybridization (FISH).\u003c/b\u003e All PCR-positive cases were further evaluated for ALK rearrangements using a dual-color break-apart FISH assay. Analyses were performed on 3-\u0026micro;m FFPE sections using locus-specific bacterial artificial chromosome (BAC) probes targeting ALK (2p23.2; RP11-418E15 and RP11-203K5; Invitrogen), labeled with Spectrum Green and Spectrum Red by nick translation (Abbott Molecular, Chicago, IL, USA), according to the manufacturer\u0026rsquo;s instructions.\u003c/p\u003e \u003cp\u003eSections were deparaffinized, rehydrated, and subjected to pretreatment, followed by denaturation at 73\u0026deg;C for 5 min and overnight hybridization at 37\u0026deg;C in a humidified chamber. Post-hybridization washes included stringent washes at 65\u0026deg;C and non-stringent washes at room temperature. Slides were counterstained with ProLong Gold Antifade Mountant containing DAPI (Invitrogen).\u003c/p\u003e \u003cp\u003eFluorescence signals were analyzed using a Zeiss fluorescence microscope (Zeiss, Oberkochen, Germany) equipped with ISIS image analysis software (MetaSystems, Altlussheim, Germany). For each case, 100 intact, non-overlapping interphase nuclei were evaluated. Normal nuclei displayed two fused (yellow) signals, whereas rearranged nuclei exhibited one fused signal and separate red and green signals. Cases were classified as ALK-rearranged when \u0026gt;\u0026thinsp;10% of nuclei demonstrated split signals, according to thresholds established using normal thyroid tissue controls, as previously described [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eALK Immunohistochemistry (IHC).\u003c/b\u003e ALK protein expression was evaluated by immunohistochemistry as a surrogate marker for kinase fusion-driven overexpression of chimeric ALK proteins [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Analyses were performed on 3-\u0026micro;m sections of formalin-fixed, paraffin-embedded (FFPE) tissue. Following deparaffinization and rehydration, endogenous peroxidase activity was quenched with 3% hydrogen peroxide for 30 min. Antigen retrieval was carried out in Tris-EDTA buffer (pH 9.0) using a pressure cooker. Non-specific binding was blocked with 5% goat serum in TBST for 1 hour at room temperature. Sections were incubated overnight at 4\u0026deg;C with a rabbit monoclonal anti-ALK antibody (clone D5F3; dilution 1:50; Cell Signaling Technology, Danvers, MA, USA). Immunodetection was performed using the EnVision Dual Link system (Agilent Technologies, Santa Clara, CA, USA), followed by hematoxylin counterstaining. Appropriate positive and negative controls were included in each run, consisting of commercially available formalin-fixed, paraffin-embedded cell line pellets provided by Cell Signaling Technology, with known ALK expression status, and processed in parallel with study samples to ensure assay specificity and optimal staining performance. ALK staining intensity and subcellular distribution were independently assessed by light microscopy. Samples were considered IHC positive if tumor-specific staining of any intensity was present in \u0026ge;\u0026thinsp;10% of the tumor cell.\u003c/p\u003e \u003cp\u003e \u003cb\u003eIn silico\u003c/b\u003e \u003cb\u003estructural and functional analysis\u003c/b\u003e. Predicted protein sequences derived from \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion transcripts were generated using the ExPASy Translate Tool [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Open reading frames were selected based on the first in-frame methionine and minimal instability index, prioritizing predicted protein stability. Physicochemical properties, including protein length, molecular weight, theoretical isoelectric point, amino acid composition, grand average of hydropathicity (GRAVY), aliphatic index, and estimated half-life, were computed to support functional inference.\u003c/p\u003e \u003cp\u003eThree-dimensional structural models were generated using the Phyre2 platform [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] based on homology modeling. Predicted structures were compared with canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion proteins to assess domain architecture, integrity of the ALK kinase domain, and potential structural consequences for dimerization and ligand-independent activation. These analyses were used to infer the functional relevance of identified fusion variants.\u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical analysis.\u003c/b\u003e Statistical analyses were performed using RStudio and GraphPad Prism 10. Categorical variables (e.g., sex) were compared using Pearson\u0026rsquo;s Chi-square test or Fisher\u0026rsquo;s exact test, as appropriate. Continuous variables (e.g., age and tumor size) were analyzed using Student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e-test or one-way ANOVA, depending on the number of groups. When applicable, the Bonferroni correction was applied to adjust for multiple comparisons. A \u003cem\u003ep\u003c/em\u003e-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cb\u003eDetection of Canonical and Structurally Divergent\u003c/b\u003e \u003cb\u003eSTRN::ALK\u003c/b\u003e \u003cb\u003eFusions in Oncocytic Thyroid Tumors\u003c/b\u003e\u003c/p\u003e \u003cp\u003eRT-PCR screening identified \u003cem\u003eSTRN::ALK\u003c/em\u003e transcripts in 9 of 56 cases of oncocytic thyroid tumors (16%). Two OTCs yielded an amplicon of approximately 100 bp, consistent with the expected size of the canonical in-frame \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion. In contrast, the remaining seven positive tumors (five OTCs and two OTAs) exhibited a shorter amplicon of approximately 50 bp (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCloning and Sanger sequencing defined the fusion's architecture. The 94 bp amplicons corresponded to the canonical in-frame fusion between \u003cem\u003eSTRN\u003c/em\u003e exon 3 and \u003cem\u003eALK\u003c/em\u003e exon 20 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB, C). In contrast, all shorter amplicons involved the same exon pairing but exhibited structurally altered junctions, characterized by internal deletions and breakpoint shifts that disrupt the reading frame (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD, E).\u003c/p\u003e \u003cp\u003eBased on junction structure, \u003cem\u003eSTRN::ALK\u003c/em\u003e-positive tumors segregated into canonical in-frame fusions (cases 5 and 10) and noncanonical out-of-frame variants. The latter comprised two recurrent subclasses: Type I variants, defined by frameshifted junctions with altered codon phasing (cases 4, 9, 11, and 12), and Type II variants, in which the frameshift introduces a premature termination codon (cases 7, 28, and 40) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eF and Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\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 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of molecular and immunohistochemical findings in \u003cem\u003eSTRN::ALK\u003c/em\u003e-positive tumors.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" 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=\"char\" char=\".\" 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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCase ID\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiagnosis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRT-PCR product size (bp)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFusion type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eALK-rearranged nuclei (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eALK IHC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ePredicted kinase activity\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eImpaired\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCanonical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePositive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFull\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eInactive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eImpaired\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCanonical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePositive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFull\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eImpaired\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eImpaired\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eInactive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOut-of-frame Type II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eInactive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eOTC: Oncocytic Thyroid Carcinoma; OTA: Oncocytic Thyroid Adenoma.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eGenomic Validation Confirms\u003c/b\u003e \u003cb\u003eALK\u003c/b\u003e \u003cb\u003eRearrangement Across Canonical and Noncanonical Variants\u003c/b\u003e\u003c/p\u003e \u003cp\u003eBreak-apart FISH confirmed \u003cem\u003eALK\u003c/em\u003e rearrangement in all nine RT-PCR-positive tumors, with split signals detected in 12\u0026ndash;58% of nuclei (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). Rearrangement signals were observed in both canonical in-frame cases (Case 5, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB; Case 10, Supplementary Fig.\u0026nbsp;1) and out-of-frame variants (Case 4, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC; cases 7, 9, 11, 12, 28, and 40, Supplementary Fig.\u0026nbsp;1).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eFusion Architecture Determines ALK Protein Expression\u003c/h3\u003e\n\u003cp\u003eDiffuse cytoplasmic ALK staining was detected exclusively in OTCs harboring canonical in-frame \u003cem\u003eSTRN::ALK\u003c/em\u003e fusions (Case 5, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA; Case 10, Supplementary Fig.\u0026nbsp;2). In contrast, all tumors carrying out-of-frame variants lacked detectable ALK expression (Case 4, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB; Cases 7, 9, 11, 12, 28, and 40, Supplementary Fig.\u0026nbsp;2). Matched adjacent normal thyroid tissue was consistently negative.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eStructural Modeling Reveals Loss of Kinase Integrity in Out-of-frame Variants\u003c/h3\u003e\n\u003cp\u003eHomology-based modeling demonstrated that the canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e fusion preserves the structural integrity of the ALK kinase domain, supporting a catalytically competent configuration (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). In contrast, all out-of-frame variants exhibited marked structural disruption and segregated into two recurrent architectures. Type I variants (Cases 4, 9, 11, and 12) were predicted to encode proteins of approximately 685 amino acids with internal deletions disrupting kinase domain continuity, retaining only a limited portion of the ALK-derived sequences exhibiting increased structural disorder. Type II variants (Cases 7, 28, and 40) generated severely truncated proteins of approximately 145 amino acids due to premature termination, aligning exclusively to \u003cem\u003eSTRN\u003c/em\u003e-derived regions and lacking ALK coding sequence (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eStructural similarity analysis corroborated these observations. Type I variants displayed weak similarity to canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e, whereas Type II variants exhibited minimal structural correspondence, consistent with the absence of ALK-derived domains. Accordingly, structure-based functional inference predicted preserved kinase activity for canonical fusions, impaired activity in Type I variants, and complete loss of kinase function in Type II variants (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC). Additional physicochemical parameters are provided in Supplementary Table\u0026nbsp;1.\u003c/p\u003e \u003cp\u003e \u003cb\u003eCanonical\u003c/b\u003e \u003cb\u003eSTRN::ALK\u003c/b\u003e \u003cb\u003efusions Are Restricted to Malignant Oncocytic Tumors\u003c/b\u003e\u003c/p\u003e \u003cp\u003eClinicopathological features of \u003cem\u003eSTRN::ALK\u003c/em\u003e-positive tumors are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Canonical in-frame fusions were identified exclusively in OTC, supporting their restriction to malignant oncocytic neoplasms within this cohort.\u003c/p\u003e \u003cp\u003eNo significant differences in baseline clinicopathological features, including patient age, tumor size, or other indicators of tumor aggressiveness, were observed between tumors harboring canonical fusions and those with out-of-frame variants. However, these analyses were limited by sample size and were not powered to detect subtle differences.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo our knowledge, this is the first study to identify \u003cem\u003eSTRN::ALK\u003c/em\u003e fusions in oncocytic thyroid carcinoma and to demonstrate that these rearrangements comprise structurally and functionally distinct entities. Using an integrated multiplatform approach, we show that although \u003cem\u003eALK\u003c/em\u003e rearrangement is consistently detectable at the genomic level, only canonical in-frame fusions result in detectable ALK protein expression. These findings demonstrate that fusion architecture, rather than the mere presence of a genomic rearrangement, is the key determinant of functional activation.\u003c/p\u003e \u003cp\u003eMost \u003cem\u003eSTRN::ALK\u003c/em\u003e-positive tumors in this cohort harbored noncanonical, out-of-frame fusion transcripts involving the same exon pairing (\u003cem\u003eSTRN\u003c/em\u003e exon 3 and \u003cem\u003eALK\u003c/em\u003e exon 20) but disrupted by internal deletions and shifted breakpoints. While consistently detected by break-apart FISH, these variants do not preserve the reading frame. Structural modeling predicted that such alterations result in partial or complete loss of the ALK kinase domain, in contrast to canonical fusions, which retain structural integrity consistent with oncogenic activation.\u003c/p\u003e \u003cp\u003eThese structural differences translated into clear protein-level consequences. ALK expression by immunohistochemistry was restricted to tumors harboring canonical in-frame fusions, whereas all out-of-frame variants were immunonegative, despite confirmed genomic rearrangement. In this context, ALK IHC appears to identify biologically active fusions rather than simply reflecting rearrangement status.\u003c/p\u003e \u003cp\u003eThese findings provide a mechanistic explanation for potential discordance between FISH and IHC results and underscore a critical diagnostic limitation. Such discrepancies have been reported in several tumor types, including thyroid [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] and may be particularly relevant in oncocytic thyroid neoplasms, which are characterized by mitochondrial accumulation and widespread genomic instability, potentially favoring the emergence of nonfunctional rearrangements [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe observation that canonical \u003cem\u003eSTRN::ALK\u003c/em\u003e fusions occur in oncocytic thyroid carcinomas, whereas noncanonical variants were observed in both carcinomas and adenomas, further supports the notion that only structurally intact fusions contribute to tumorigenesis. Noncanonical variants may instead represent passenger events arising from genomic instability, consistent with their predicted loss of kinase function.\u003c/p\u003e \u003cp\u003eThese findings also have potential clinical implications. As the therapeutic response to ALK inhibitors depends on the presence of a functional kinase, accurate identification of biologically active fusions is essential. In this context, the integration of molecular and protein-based assays may improve patient selection, particularly in oncocytic thyroid carcinomas, which often exhibit limited responsiveness to conventional therapies [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Consistent with this, although uncommon, ALK rearrangements have been described in papillary thyroid carcinoma and extend across the spectrum of aggressive thyroid malignancies, including poorly differentiated and anaplastic thyroid carcinomas [\u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study has limitations. Functional activity was inferred from structural modeling and protein expression rather than directly assessed in experimental systems. In addition, the modest sample size limits clinicopathological correlations. Further studies are warranted to determine the prevalence and significance of similar noncanonical fusions in broader thyroid tumor cohorts and to validate their biological behavior\u003c/p\u003e \u003cp\u003eIn summary, \u003cem\u003eSTRN::ALK\u003c/em\u003e rearrangements in oncocytic thyroid tumors comprise two biologically distinct entities: rare canonical in-frame fusions that preserve kinase function and more frequent noncanonical variants that are structurally disrupted and likely nonfunctional. These findings underscore the importance of integrative molecular assessment and caution against associating genomic rearrangement with functional activation, particularly when selecting patients for targeted therapies. Together, they highlight the need for combined molecular and protein-based approaches when evaluating \u003cem\u003eALK\u003c/em\u003e rearrangements, especially in oncocytic thyroid tumors, where genomic instability may give rise to nonfunctional alterations.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCode availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e \u003cp\u003eThis study was approved by the Brazilian National Research Ethics Committee (CAAE: 56882116.7.0000.550). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The requirement for informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent to Participate\u003c/strong\u003e \u003cp\u003eInformed consent was waived by the institutional review board because of the retrospective nature of this study, which used anonymous clinical data.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for Publication\u003c/strong\u003e \u003cp\u003eAll authors approved for the publication of this paper\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompeting Interests\u003c/strong\u003e \u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis study was supported by research grants from the S\u0026atilde;o Paulo Research Foundation (FAPESP; grant numbers 2014/06570-6 and 2022/09713-9) and National Council for Scientific and Technological Development (CNPq; grant number 406952/2022-1). D.M.D.T., T.B.M., and L.S. received fellowship support from FAPESP (grant numbers 2020/06594-3, 17/06487-0, and 18/09911-0). T.N.R.C. received a fellowship from the CNPq. J.M.C. was awarded a Research Productivity Scholarship from CNPq (grant number 304534/2018-8). We also acknowledge financial support from CAPES.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Data curation, formal analysis, investigation, and visualization were performed by Debora Mota Dias Thomaz. Methodology was developed by Debora Mota Dias Thomaz, Thais Biude Mendes, Thaise Nayane Ribeiro Carneiro, and Luiza Sisdelli. Validation was performed by Debora Mota Dias Thomaz and Ana Carolina de Jesus Paniza. Resources, funding acquisition, and supervision were provided by Janete Maria Cerutti. Project administration was carried out by Debora Mota Dias Thomaz and Janete Maria Cerutti. The first draft of the manuscript was written by Debora Mota Dias Thomaz, and all authors (Thais Biude Mendes, Thaise Nayane Ribeiro Carneiro, Luiza Sisdelli, Ana Carolina de Jesus Paniza, Andr\u0026eacute; Uchimura Bastos, and Janete Maria Cerutti) contributed to the review and editing of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll data supporting the findings of this study are available within the paper and its Supplementary Information.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eVaio F, Moliterni C, Mardente S, Misasi R, Mari E (2026) State of the Art on Thyroid Cancer Biology and Oncology. 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Endocr Pathol 35:134\u0026ndash;146. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12022-024-09808-1\u003c/span\u003e\u003cspan address=\"10.1007/s12022-024-09808-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\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":"endocrine-pathology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"enpa","sideBox":"Learn more about [Endocrine Pathology](http://link.springer.com/journal/12022)","snPcode":"12022","submissionUrl":"https://submission.nature.com/new-submission/12022/3","title":"Endocrine Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Oncocytic Thyroid Neoplasms, Anaplastic Lymphoma Kinase, ALK Fusion Proteins, Immunohistochemistry, Fluorescence In Situ Hybridization","lastPublishedDoi":"10.21203/rs.3.rs-9360178/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9360178/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eOncocytic thyroid carcinoma (OTC) represents a distinct subtype of thyroid cancer characterized by marked genomic complexity and frequent resistance to radioactive iodine therapy, highlighting the need for refined molecular stratification. Rearrangements involving \u003cem\u003eALK\u003c/em\u003e gene, particularly \u003cem\u003eSTRN::ALK\u003c/em\u003e fusions, have been described in thyroid neoplasia and may confer susceptibility to targeted inhibition; however, their functional and clinical relevance in oncocytic tumors remains poorly defined. To date, \u003cem\u003eSTRN::ALK\u003c/em\u003e alterations have not been systematically investigated in this histologic subtype.\u003c/p\u003e \u003cp\u003eHere, we provide the first comprehensive evaluation of ALK rearrangements in a cohort of 56 oncocytic thyroid tumors using an integrated multiplatform approach that combines transcript-level detection, genomic validation, protein expression profiling, and in silico structural modeling. \u003cem\u003eSTRN::ALK\u003c/em\u003e transcripts were identified in 16% of cases and comprised both canonical in-frame fusions and structurally divergent noncanonical variants involving identical exon partner. Although \u003cem\u003eALK\u003c/em\u003e rearrangement was confirmed by FISH in all positive cases, protein expression was strictly confined to OTC harboring canonical in-frame fusions. In contrast, noncanonical variants displayed altered fusion junctions with frameshift configurations predicted to abrogate kinase function. Consistently, structural modeling demonstrated preservation of the catalytic kinase domain in canonical fusions and profound structural disruption in noncanonical variants.\u003c/p\u003e \u003cp\u003eThese findings establish that fusion architecture, rather than the mere presence of genomic rearrangement, is the key determinant of functional activation. This study expands the molecular landscape of oncocytic thyroid tumors and underscores the importance of integrating molecular and protein-based approaches to accurately identify biologically active fusions, with direct implications for patient selection and therapeutic decision-making.\u003c/p\u003e","manuscriptTitle":"Characterization of STRN::ALK Fusions in Oncocytic Thyroid Tumors Reveals Fusion Architecture as a Determinant of Functional ALK Activation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-23 09:32:11","doi":"10.21203/rs.3.rs-9360178/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-28T03:49:27+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-27T15:15:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-25T15:53:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"110529577377853887894225991466649660087","date":"2026-04-16T14:41:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"32761205853268893018029007621933943154","date":"2026-04-16T07:23:40+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-16T03:15:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-09T07:03:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-09T07:02:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Endocrine Pathology","date":"2026-04-08T17:56:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"endocrine-pathology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"enpa","sideBox":"Learn more about [Endocrine Pathology](http://link.springer.com/journal/12022)","snPcode":"12022","submissionUrl":"https://submission.nature.com/new-submission/12022/3","title":"Endocrine Pathology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f86e7f7c-67d3-4992-ab0c-97d386e2a2dd","owner":[],"postedDate":"April 23rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-19T03:11:00+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-23 09:32:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9360178","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9360178","identity":"rs-9360178","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}