Differential expression of miR-98-5p and DICER1 in eutopic versus ectopic endometrium: a diagnostic biomarker signature for endometriosis

Biomarker, DICER1, Endometriosis, Gene expression, MiR-98-5p, miRNA 1. Introduction Endometriosis is a chronic, estrogen - dependent gynecological disorder defined by the prese nce of endometrial -like tissue outside the uterine cavity. Affecting approximately 10% of women of reproductive age globally, it represents a significant cause of morbidity and reduced quality of life [1]. Although histologically benign, endometriosis exhibits cancer -like characteristics such as progressive, invasive growth, a high recurrence rate, and metastatic potential [2]. The clinical presentation commonly includes chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility, which affects nearly 30–50% of women with the conditi on [3]. The pathogenesis of endometriosis remains multifactorial and incompletely elucidated. While Sampson’s theory of retrograde me nstruation remains the most Original Article Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 171 | P a g e widely accepted model, it alone cannot explain all cases. Recent findings emphasize the significance of epigenetic changes, such as DNA methylation and miRNA dysregulation, which affect gene expression in ectopic lesions [4]. Recent advances in multi -omics technologies, encompassing genomics, transcriptomics, epigenomics, and proteomics, have significantly expanded our understanding of the molecular landscape of endometriosis [5]. These approaches have identified n umerous genes and pathways associated with the disease, highlighting significant dysregulation in critical biological processes, including hormone response, inflammation, cell adhesion, and apoptosis [6]. MicroRNAs (miRNAs) are small non-coding RNA molecules, approximately 22 nucleotides in length that function as crucial post - transcriptional regulators of gene expression [7, 8]. Through imperfect base -pairing with target mRNAs, miRNAs typically induce translational repression or mRNA degradation, thereby fine -tuning fundamental cellular processes including proliferation, differentiation, apoptosis, and inf lammatory responses. Non -coding RNAs, particularly microRNAs (e.g., miR -451, miR -141-3p) and long non-coding RNAs (e.g., H19, MEG3), serve as critical post -transcriptional regulators, influencing mRNA stability and translation. Recent research has discover ed more than 50 differentially expressed microRNAs in ectopic and eutopic endometrial tissues from individuals diagnosed with endometriosis, revealing their central role in the pathogenesis of the disease [9]. Functional in vitro studies reveal that dysregulation of specific miRNAs, specifically the downregulation of the miR-200 family and the upregulation of miR -21-5p, facilitates epithelial-mesenchymal transition (EMT), enhances cellular migration and invasion, and provides resistance to apoptosis [10]. Due to their stability in biofluids, circulating miRNAs have attracte d considerable attention as potential non -invasive biomarkers. Recent investigations utilizing high -throughput miRNA profiling of serum and plasma have identified multi -miRNA signatures with promising diagnostic accuracy for endometriosis, including combin ations such as miR -125b-5p, miR -28-5p, and let -7b-5p [11]. Bioinformatic analyses suggest that dysregulated miRNAs target crucial genes involved in endometriosis -associated pathways, including estrogen receptor (ER) and progesterone receptor (PR ) signaling, TGF-β-mediated cell invasion, and extracellular matrix remodeling [12]. Among these miRNAs, miR-98-5p has emerged as a candidate of particular interest due to its established role as a key regulator of inflammatory and fibrotic pathways, core processes in endometriosis establishment and maintenance. Initially identified in cancer, miR-98-5p acts as a key modulator of core oncogenic pathways, including PI3K/AKT (pro-survival signaling), Wnt/β -catenin (proliferation and stemness), and the epithelial-to-mesenchymal transition (EMT) (invasion and metastasis) [13]. Notably, these same pathways are co -opted in the pathogenesis of endometriosis, a benign but locally invasive disorder characterized by the survival, proliferation, and invasive potential of ectopic endometrial tissue. Recent evidence has begun to shed light on its involvement in endometriosis, suggesting a conserved role for miR-98-5p in regulating the cellular processes that drive both malignant and non - malignant tissue invasion. Also, it was confirmed that miR-98-5p acts as a powerful tumor suppressor in multiple cancer types, including nasopharyngeal carcinoma, endometrial cancer, and ovarian cancer, where it is frequently downregulated [14]. MiR-98-5p is an evolutionarily conserved, endogenous microRNA located on the X chromosome (Xp11.22) and is a significant member of the let -7 tumor suppressor family. The mature sequence (5′ - ugagguaguaaguuguauuguu-3′) contains a highly conserved “seed region” (nucleotides 2–8) that is essential for target recognition and binding specificity ( Figure 1). Structural analyses sug gest that its secondary structure and sequence conservation enable it to regulate a broad network of mRNAs involved in cell cycle, invasion, and differentiation [13]. Notably, in gynecological conditions such as endometriosis, miR-98-5p is significantly underexpressed and is thought to play a role in disease progression due to the loss of its regulatory function. Its ability to modulate key pathways, including TGF -β, Wnt/β -catenin, and STAT3 signaling, depending on cellular 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 172 | P a g e context, further supports its role as a critical epigenetic regulator in both cancer and benign proliferative disorders [10]. Fig. 1. The precursor and mature sequence of MiR-98-5p (miRVim: Human miRNA structure database) features a highly conserved "seed region" (nucleotides 2 –8) that is crucial for target recognition and binding specificity. The biogenesis of miR-98-5p is regulated by several cellular factors, including transcriptional controls, epigenetic modifications, and core microprocessor components. Key to its maturation is the Drosha-DGCR8 complex located in the nucleus and the DICER1 enzyme found in the cytoplasm. Any mutations or dysregulation of these complexes can significantly impair the conversion of pre -miR-98 into its mature, functional form [15]. The DICER1 protein (UniProt: Q9UPY3) serves as a crucial ribonuclease III enzyme that is vital for miRNA biogenesis. In terms of structure, it possesses an N -terminal DEXH -box RNA helicase domain that aids in the ATP - dependent unwinding of RNA substrates, along with a C -terminal RNase III domain that is responsible for cleaving pre -miRNAs into mature duplexes. Recent multi-omics research has shown that DICER1 expression is frequently downregulated in various cancers, leading to a widespread decrease in mature miRNAs. This phenomenon is particularly evident in epithelial ovarian cancer (EOC), where diminis hed levels of DICER1 are associated with advanced tumor stages, metastasis, and unfavorable prognosis [16]. These findings emphasize the essential function of miRNA biogenesis machinery in the development of cancer a nd point out DICER1 as not only a biomarker but also a promising therapeutic target for reinstating tumor-suppressive miRNA activity. Although the roles of microRNA dysregulation and compromised miRNA biogenesis in endometriosis are well -established, the precise roles of miR-98-5p and its regulatory interaction with DICER1 in both ectopic and eutopic endometrial tissues are still inadequately defined. To fill this knowledge void, we conducted a comprehensive bioinformatics and experimental investigation utilizing gene expression profiles from public Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 173 | P a g e databases in conjunction with original molecular data from a cohort of Iranian patients. The rationale for investigating the interaction between miR-98-5p and DICER1 in endometriosis extends beyond their concurrent dysregulation. While the downregulation of miR-98-5p aligns with the disease's pro -proliferative and invasive phenotype, the parallel decrease in its essential processing enzyme, DICER1, suggests a potential mechanistic link. We therefore explicitly hyp othesize that the impaired expression and function of DICER1 is a direct molecular cause of the pathological depletion of mature miR-98-5p in endometriotic lesions. This disruption in the microRNA biogenesis pathway represents a novel pathogenic mechanism in endometriosis, potentially explaining the sustained imbalance in key downstream signaling networks. Consequently, this study aims not merely to document this correlation but to functionally test this hypothesis, positioning the DICER1/miR-98-5p axis as a central regulatory node and a potential therapeutic target. 2. Materials and methods 2.1. Ethical considerations Each participant filled out a comprehensive, structured questionnaire designed to collect extensive epidemiological and clinical informatio n. This instrument collected data on reproductive history (parity, gravidity, and contraceptive use), menstrual characteristics (cycle length, dysmenorrhea severity, and bleeding patterns), medical and surgical history, family history of endometriosis or o ther gynecological disorders, and lifestyle factors (including physical activity, dietary habits, and environmental exposures). In accordance with current endometriosis research frameworks, the questionnaire incorporated validated instruments for pain mapp ing and symptom characterization, including specific metrics for dyschezia, dysuria, dyspareunia, and cyclical bowel or urinary symptoms. Furthermore, information regarding previous surgical reports, histopathological confirmations, and imaging findings wa s systematically recorded to enhance phenotypic stratification. 2.2. Patient’s criteria This case -control study enrolled 30 patients with endometriosis and 35 control participants between 2020 and 2023 (Table 1). Participants were women aged 18 –45 years with a body mass index (BMI) ≤30 kg/m², non -pregnant, non -lactating, premenopausal, and without chronic diet - related or endocrine disorders including diabetes, cardiovascular disease, renal dysfunction, or reproductive tract malignancies. Endometriosis di agnosis was confirmed surgically and histologically according to the Enzian classification or ASRM staging system at Shahid Sadoughi Hospital, Yazd. Cases consisted of women with visual or histopathologically proven endometriosis, while controls were indiv iduals without endometriosis undergoing laparoscopy/laparotomy for other benign gynecological indications (e.g., benign ovarian cysts, infertility evaluation, or elective tubal ligation). Controls had no history of endometriosis symptoms, chronic pelvic pa in, or previous abdominal surgery and were matched to cases by age (±3 years) to minimize potential confounding effects. All participants exhibited regular menstrual cycles (24–38 days) for at least three months prior to enrollment. Exclusion criteria encompassed polycystic ovary syndrome (PCOS), chronic anovulation, hydrosalpinx, endocrinopathies, dyslipidemia, autoimmune conditions (e.g., systemic lupus erythematosus), HIV or active infections, and recent (3 -month) use of hormonal therapy, anti-inflammatory drugs, tobacco, alcohol, or recreational substances. The diagnoses and eligibility assessments were verified by board-certified obstetrician -gynecologists. All tissue collections were performed during scheduled laparoscopic procedures for endometriosis diagnosis and treatment. Ectopic tissues were precisely excised from visually confirmed endometriotic lesions, while matched eutopic endometrial samples were simultaneously obtained from the uterine cavity using gentle curettage to ensure histological viab ility. All tissue specimens were immediately snap -frozen in liquid nitrogen and stored at -80°C until RNA extraction to preserve RNA integrity. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 174 | P a g e Table 1. Overview of the characteristics of participants diagnosed with endo metriosis and the control group Characteristic Endometriosis Group (n=30) Control Group (n=35) p-value Demographics Age (years), mean ± SD 32.5 ± 5.1 31.8 ± 4.7 0.55 BMI (kg/m²), mean ± SD 24.1 ± 3.8 23.7 ± 4.2 0.68 Clinical History Parity, median [IQR] 1 [0, 2] 1 [1, 2] 0.42 Age at Menarche (years), mean ± SD 12.4 ± 1.3 12.6 ± 1.1 0.48 Menstrual Cycle Length (days), mean ± SD 28.5 ± 2.5 28.8 ± 2.1 0.58 Pain Symptoms (VAS 0-10), mean ± SD Dysmenorrhea (Menstrual pain) 8.1 ± 1.5 5.2 ± 2.3 <0.001 Dyspareunia (Pain during intercourse) 6.4 ± 2.8 1.5 ± 1.9 <0.001 Chronic Pelvic Pain 7.2 ± 2.1 1.8 ± 1.7 <0.001 rASRM Stage, n (%) Stage I-II (Minimal-Mild) 12 (40.0%) — — Stage III-IV (Moderate-Severe) 18 (60.0%) — — 2.3. Total RNA extraction and cDNA synthesis Fresh ectopic and eutopic endometrial tissue specimens were collected during surgery, immediately snap -frozen in liquid nitrogen, and stored at −80°C to preserve RNA integrity. Total RNA was extracted from 50 – 100 mg of tissue using TRIzol™ reagent (Invitrogen, USA), following the manufacturer's protocol. RNA concentration and purity were assessed spectrophotometrically (NanoDrop™ 2000, Thermo Fisher Scientific, USA), with acceptable 260/280 ratios ranging from 1.8 to 2.1. RNA integrity was further verified using an A gilent 2100 Bioanalyzer RNA Nano Chip, with all samples having an RNA Integrity Number (RIN) ≥7. Complementary DNA (cDNA) was synthesized from 1 µg of total RNA using the PrimeScript™ RT reagent Kit (Takara Bio, Japan) with specific stem -loop primers for miR-98-5p and oligo(dT) primers for DICER1 mRNA, enabling specific detection of mature miRNA and mRNA transcripts. Reverse transcription was performed in a 20 µL reaction volume using a ProFlex™ PCR System (Applied Biosystems, USA) under the following condi tions: 37°C for 60 min, followed by heat inactivation at 85°C for 5 min, and hold at 4°C. cDNA products were stored at −20°C until subsequent qPCR analysis. 2.4. Microarray data analysis To identify differentially expressed genes (DEGs) associated with endometriosis, we integrated and reanalyzed five publicly available transcriptomic datasets from the Gene Expression Omnibus (GEO). All datasets were generated using the Affymetrix HG-U133 Plus 2.0 platform (GPL570), ensuring technical consistency. The following datasets were included: GSE25628: Transcriptional profiling of endometrial biopsies (16 e utopic endometrial samples from patients, 7 ectopic lesions, and 6 eutopic endometrial samples from healthy controls; 29 unique individuals), GSE23339: Gene expression in endometriosis (10 eutopic endometrial samples from patients and 9 from controls; 19 u nique individuals), GSE7846: Differentially expressed genes in human endometrial endothelial cells (HEECs) from eutopic endometrium (6 patients and 4 controls; 10 unique individuals), GSE6364: Endometrial profiling highlighting progesterone resistance (21 eutopic endometrial samples from endometriosis patients and 16 eutopic endometrial samples from healthy controls; 37 unique individuals), and GSE5108: Genome-wide comparison of 10 eutopic endometrial samples and 12 ectopic lesion samples from the same 10 i ndividuals (10 paired samples, plus 2 additional ectopic lesions). In total, the integrated cohort comprised 100 samples (69 endometriosis cases, 31 controls), providing robust statistical power for differential expression analysis. The integrated cohort c omprised a total of 100 individual tissue samples. To ensure statistical independence and avoid pseudoreplication, samples were treated as belonging to two primary biological groups for the initial differential expression analysis: "Disease" and "Control". The "Disease" group (n=69 samples) included all ectopic lesions and all eutopic endometrial samples obtained Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 175 | P a g e from patients diagnosed with endometriosis. The "Control" group (n=31 samples) consisted exclusively of eutopic endometrial samples from individua ls without surgical or histological evidence of endometriosis. Raw CEL files were processed using the oligo R package for background correction, normalization (RMA algorithm), and probe summarization. Differential expression between the consolidated Disease and Control groups was determined using the limma package with adjusted p-values (Benjamini - Hochberg FDR 1. 2.5. Differential Gene Expression (DGE) Analysis Differential gene expression analysis between ectopic and euto pic endometrial samples was performed using GEO2R, an interactive web tool for comparing GEO datasets. We conducted comparative analyses across both endometriosis and control groups to identify tissue -specific and disease -specific transcriptional changes. Visualization of expression patterns was achieved using the ggplot2 and pheatmap packages in R, generating volcano plots and hierarchical clustering heatmaps to illustrate global transcriptomic differences. Genes with an adjusted P-value <0.05 (Benjamini –Hochberg correction) and |log ₂ fold change| ≥ 1 were considered differentially expressed. To prioritize biologically relevant changes, we applied a stricter threshold of |log ₂FC| > 2 for downstream functional enrichment analyses. 2.6. Gene Ontology (GO) function and KEGG pathway assessment To elucidate the biological significance of the identified differentially expressed genes (DEGs) and miRNAs, we performed comprehensive functional enrichment analysis using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. Analyses were executed with the clusterProfiler package (v4.0) in R, leveraging annotations from the UCSC Genome Browser to ensure up -to-date genomic context. Gene Ontology (GO) analysis provides a framework for defining gene functions and interactions related to various biological events, biological processes (Identifying overarching physiological pathways), cellular components (Determining subcellular localization), and molecular functions (Defining biochemical activities). KEGG pathway analysis revealed involvement in key signaling cascades, including Wnt, TGF -β, and JAK-STAT pathways, which are critically implicated in endometriosis pathogenesis. Enrichment significance was assessed using a false discovery rate (FDR)-adjusted P-values 1.5 to ensure biological relevance. 2.7. Protein –Protein Interactions (PPI) network analysis To systematically evaluate the functional relationships between DICER1 and the identified differentially expressed genes (DEGs) in Homo sapiens, we constructed and analyzed protein -protein interaction (PPI) networks using multiple complementary databases. The STRING database (v12.0) and SIGNOR were employed to retrieve experimentally validated and predicted interactions, applying a high -confidence score threshold of > 0.9 to ensure biological relevance. To enhance the robustness and coverage of the network, we integrated data from FunCoup 4.0 and BioGRID (v4.4), which provide e xtensive context -specific functional associations, including genetic, physical, and regulatory interactions. The combined network was visualized and topologically analyzed using Cytoscape (v3.10.0), with the NDEx platform enabling public sharing, repository integration, and collaborative exploration of the network models. Key network properties, such as degree centrality and clustering coefficients, were calculated using Cytoscape plugins (e.g., CytoHubba, MCODE) to identify hub genes and functionally significant modules. 2.8. MiRNA target prediction and pathway enrichment Analysis To systematically identify miR-98-5p target mRNAs and evaluate their functional roles, we integrated predictions from multiple 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 176 | P a g e bioinformatic tools specializing in miRNA - mRNA int eractions. These included TargetScan (v8.0), miRDB (v6.0), miRWalk (v3.0), DIANA -microT-CDS (v5.0), and miRanda (v3.3a), leveraging both evolutionary conservation and context - specific binding models. Experimentally validated interactions were further cross - referenced using tarBase (v9.0) and miRTarBase (v10.0). To transcend mere target prediction and elucidate the systems - level impact of miR-98-5p, we performed integrative functional enrichment analysis. Signaling pathways and biological processes associated with predicted targets were analyzed using KEGG, DIANA -miRPath (v4.0), and GeneCodis (v6.0), with statistical significance defined by an adjusted P-value < 0.05 (Benjamini -Hochberg correction). Gene Ontology (GO) term overrepresentation was assessed for biological process, cellular component, and molecular function categories. Pathway perturbation dynamics were quantitatively evaluated using Signaling Pathway Impact Analysis (SPIA), which combines overrepresentation and topological measures to identify dy sregulated pathways. To contextualize miR-98-5p expression, we analyzed data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and miRBase (v22.1), focusing on endometriosis and related gynecological conditions. 2.9. Validation of differ ential gene expression by RT-qPCR To confirm the findings from transcriptomic analyses, quantitative reverse transcription PCR (RT -qPCR) was performed to measure expression levels of DICER1 and hsa-miR-98-5p in 50 endometriotic lesions and 55 matched euto pic endometrial tissues. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was employed as the endogenous control for normalization. Its suitability was rigorously evaluated prior to use by assessing its expression stability across all sample types (ectopic lesions, patient eutopic endometrium, and control eutopic endometrium). The analysis confirmed that GAPDH Ct values exhibited no statistically significant variation ( P> 0.05 by one -way ANOVA) between the different tissue groups, demonstrating its reliabil ity as a stable

gene under our experimental conditions. Complementary DNA was synthesized from total RNA using the PrimeScript RT reagent Kit (Takara Bio) with stem-loop primers for miR-98-5p and oligo(dT) primers for DICER1 and GAPDH. qPCR react ions were conducted in triplicate using SYBR Green Master Mix (Roche) in a 10 µL volume on a StepOnePlus™ Real -Time PCR System (Applied Biosystems). The thermocycling protocol consisted of an initial denaturation step at 95°C for 10 minutes, followed by 40 cycles of 95°C for 15 seconds and 61°C for 1 minute. Melting curve analysis was conducted to verify the specificity of the amplification. To prevent any non-specific amplification resulting from genomic DNA contamination, a non -reverse transcription contr ol was inc orporated into the qPCR assays. The primers utilized in this study were designed using the Gene Runner and OligoAnalyzer software. The gene -specific primers comprised those for the DICER1 gene: F: 5′ -TTCGAGCCTCCATTGTTGGTC-3′, R: 5′ - TTCCCAACTGGCATCAAATGG-3′ (amplicon size: 127 bp), and for the hsa -miR-98-5p gene: F: 5′ -GTGAGGTAGTAAGTTGTATTG-3′, R: 5ˊ - ATCACTGTAAAACCGTT-3ˊ (Universal reverse primer), yielding a 171 bp product, as well as for GAPDH: F: 5′ - AAGGTCGGAGTCAACGGATTTG-3′, R: 5′ - GCCATGGGTGGAATCATATTGG-3′. No -reverse transcription control (NRTC) and no -template control (NTC) were included to identify genomic DNA contamination and non -specific amplification. Cycle threshold (Ct) values were evaluated using the 2 –ΔΔCt method to calculate fold -change expression, with statistical significance being analyzed through Student’s t-test (P< 0.05). 2.10. Statistical analysis Data were analyzed using descriptive and inferential statistics implemented in R v4.2.0 and GraphPad Prism v9.0. Continuous variables are presented as mean ± SD or median with interquartile range (IQR) based on their distribution, and visualized using boxplots. Categorical variables are summarized as counts and percentages. Group comparisons for continuous variables Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 177 | P a g e (e.g., clinical pa rameters, RT -qPCR ΔΔCt values) were conducted using non -parametric tests (Mann -Whitney U test for two groups; Kruskal-Wallis test with Dunn’s post hoc test for more than two groups). For all analyses involving multiple pairwise comparisons, P-values were a djusted using the Benjamini -Hochberg false discovery rate (FDR) correction to control for Type I error inflation. A two -sided P-value < 0.05 (or an FDR-adjusted P-value < 0.05, as applicable) was considered statistically significant. Unadjusted and adjuste d logistic regression models were employed to evaluate risk factors associated with endometriosis. Results are reported as odds ratios (OR) with 95% confidence intervals (CI). Multivariable models adjusted for clinically relevant covariates, including age at menarche, cycle length, bleeding duration, parity, gravidity, miscarriage history, contraceptive use, BMI, and smoking status. Model fit was assessed using the Hosmer -Lemeshow goodness -of-fit test, and multicollinearity among predictor variables was eva luated using variance inflation factors (VIF), with a VIF < 5 considered acceptable. 3. Results 3.1. Differential expression gene (DEG) analysis in endometriosis Integrated analysis of five Gene Expression Omnibus (GEO) datasets, GSE25628, GSE23339, GSE7846, GSE6364, and GSE5108, identified significant transcriptomic alterations in endometriosis. The combined cohort included 69 endometriosis patients and 31 controls, with samples representing both ectopic and eutopic endometrial tissues. A comprehensive tr anscriptomic analysis of endometriosis samples from public GEO datasets identified 45,764 expressed mRNAs, of which 1,952 were differentially expressed (adjusted P-value 1). Among these, 527 mRNAs were significantly up - regulated and 1,42 5 were down -regulated in ectopic versus eutopic endometrial tissues. This pattern of widespread transcriptional downregulation suggests a fundamental rewiring of the cellular state in ectopic lesions. We postulate that this is not a passive phenomenon but may reflect sever al active biological processes. Firstly, it could indicate a broad suppression of terminal differentiation programs, facilitating the plasticity required for lesion survival and invasion in a foreign microenvironment. Secondly, this patter n is consistent with the establishment of a more primitive or stem-like transcriptional landscape, where genes associated with mature endometrial function are silenced. This is further supported by the functional enrichment analysis, which highlighted the downregulation of pathways related to inflammatory response, extracellular matrix organization, angiogenesis, and steroid hormone signaling, processes central to endometriosis pathogenesis. Volcano plots and hierarchical clustering Heatmaps ( Figures 2 and 3) visualized the distinct segregation of endometriosis and control samples based on these DEGs. Hierarchical clustering analysis demonstrated clear segregation between endometriosis and control samples base d on these expression patterns. The most signific antly up -regulated protein-coding genes included CXCL12 (a chemokine promoting angiogenesis and immune cell recruitment), VEGFA (a master regulator of vasculogenesis, supporting lesion survival), and MMP9 (a protease facilitating tissue remodeling and inva sion). Conversely, PROKR2 (involved in endometrial apoptosis and receptivity), ESR1 (encoding the estrogen receptor alpha, central to hormonal response), and GATA6 (a transcription factor critical for endometrial differentiation and function) were among th e most down - regulated. The coordinated upregulation of pro - angiogenic and invasive factors alongside the suppression of genes essential for endometrial receptivity and hormonal signaling strongly suggests that dysregulation of this specific gene set contri butes directly to the pathogenesis of endometriosis and its associated infertility. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 178 | P a g e Fig. 2. Volcano plot of differentially expressed genes in endometriosis microarray dataset: This diagram represents the genes with significant increases and decreases ex pression in GSEs. The red color indicates significantly up-regulated genes (Log ₂FC > 1, FDR -adjusted P < 0.05), blue points represent significantly down-regulated genes (Log ₂FC < -1, FDR -adjusted P < 0.05), and gray points represent non -significant genes. Dashed vertical lines indicate ±1 log ₂ fold-change thresholds, and the horizont al dashed line represents the significance threshold ( -log₁₀ P= 1.3, equivalent to P = 0.05). FC: fold change; FDR: false discovery rate. Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 179 | P a g e Fig. 3. Heatmap of microarray data and hierarchical clustering for the top differentially expressed genes (DEGs) in the microarray datasets from control and endometriosis samples. Sample groups are explicitly annotated in the color bar above the heatmap: red indicates tissue samples, and green indicates disease state. Rows represent individual genes, columns represent individual samples. Expression values are Z - score normalized across samples, with red indicating expression above the mean and green indicating expression below the mean. Cluster dendrograms reveal distinct grouping patterns between endometriosis and control samples. 3.2. miRNAs differentially expressed in endometriosis Parallel small RNA sequencing analysis revealed 125 differentially expressed miRNAs, with 58 up -regulated and 67 down -regulated in endometriosis lesions compared with controls. The signific ant downregulation of miR-98-5p was consistently observed across both independent datasets, showing markedly lower expression in endometriosis tissues compared with normal controls ( Figure 4A, B). Crucially, the dysregulation of many of these miRNAs, inclu ding the significant downregulation of miR-98-5p, was also observed in the eutopic endometrium of patients compared with the endometrium of healthy controls. This consistent signature across both ectopic and eutopic tissues strongly suggests their potentia l involvement in early disease pathogenesis and the preconditioning of the endometrial microenvironment for lesion establishment. Other key dysregulated miRNAs included up - regulated miR -451a, miR -21-5p, and let -7b- 5p, and down -regulated miR -200c-3p and miR-29b-3p. Functional enrichment analysis revealed that these differentially expressed miRNAs are significantly involved in inflammatory response, extracellular matrix remodeling, angiogenesis, and steroid hormone signaling. These pathways are well -established hallmarks of endometriosis pathophysiology. Their concurrent dysregulation suggests a coordinated molecular disruption that may facilitate lesion survival, invasion, and progression. This multi -pathway involvement underscores the complex regulatory netw ork affected in the disease and supports the relevance of these miRNAs as potential contributors to the core biological processes driving endometriosis onset and chronic persistence. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 180 | P a g e Fig. 4. A) Expression profile of hsa-miR-98-5p across endometriosis and control endometrial tissues from the GEO dataset GDS5339. Expression levels are shown as a percentile rank within each sample, demonstrating a clear reduction in both ectopic and eutopic endometrium from patients with endometriosis compared with normal c ontrol endometrium. B) Validation of hsa -miR-98-5p downregulation in an independent cohort from the ExplORRnet database, confirming significantly lower expression in primary endometriotic tissue (n=504) compared with solid tissue normal controls (n=33). 3.3. Functional Enrichment Analysis of DICER1 and hsa-miR-98-5p Targets To elucidate the biological roles of DICER1- associated genes and the predicted targets of hsa-miR-98-5p, we conducted Gene Ontology (GO) and KEGG pathway enrichment analyses (Figure 5). The GO results demonstrated that these target genes were significantly enriched Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 181 | P a g e (FDR < 0.05) in categories linked to cell adhesion and migration. Among the most prominently enriched biological processes were epithelial -mesenchymal transition (EMT), reg ulation of cytokine -mediated signaling, and angiogenesis. Given that hsa -miR-98-5p is most frequently downregulated in cancer, its suppression leads to the derepression —and subsequent upregulation—of its target genes. A focused GO analysis of these upregul ated targets reveals a striking enrichment for processes that drive malignancy. Specifically, we observe positive regulation of cell proliferation (via targets like CCND1 and CDK4), negative regulation of apoptosis (via BCL2), induction of EMT (via TWIST1) , and promotion of angiogenesis (via VEGFA). Collectively, these findings underscore a coherent pro-oncogenic signature: when miR- 98-5p is lost, the coordinated upregulation of its targets fuels tumor progression through enhanced survival, inv asiveness, and vascular support. The enrichment of these pro -cancer pathways reveals how the loss of the tumor suppressor miR-98-5p paradoxically confers oncogenic gain -of-function upon its target genes. This mechanistic shift is further compounded by the frequent down regulation of DICER1 in malignancies. As the central enzyme for miRNA biogenesis, DICER1 depletion drastically reduces the global mature miRNA pool, thereby releasing hundreds of target transcripts from post - transcriptional repression. The consequent derepression triggers a broad transcriptomic avalanche, with Gene Ontology analyses consistently identifying significant enrichment in cell cycle progression, enhanced migratory and invasive capacity, inflammatory signaling, Wnt pathway activation, and dysregul ated metabolic reprogramming. Crucially, the impact of DICER1 loss is not pathway -specific but systemic. By crippling the production of diverse regulatory miRNAs, it eliminates the fine-tuned governance of the cellular transcriptome. This widespread regula tory collapse leads to the simultaneous and aberrant activation of multiple oncogenic hallmarks, transforming a single molecular defect into a coordinated, multifactorial driver of malignant transformation and tumor progression. At the molecular function l evel, the most enriched Gene Ontology categories included growth factor binding and transcription factor activity. Cellular component analysis revealed significant enrichment in extracellular exosomes and focal adhesions. KEGG pathway annotation further li nked these genes to several signaling cascades known to underlie endometriosis pathophysiology ( Figure 6). Notably, the TGF ‑β (FDR = 3.2e ‑05), PI3K‑Akt (FDR = 1.8e ‑04), and Wnt (FDR = 6.7e‑04) pathways emerged as the most significantly overrepresented. Alt ogether, these data demonstrate that genes co‑dysregulated with DICER1 and hsa‑miR‑98‑5p are functionally interconnected rather than dispersed. Their coordinated enrichment points toward a cohesive molecular signature that directly supports key hallmarks o f endometriotic lesion development and persistence — specifically, tissue invasion, immune evasion, and neovascularization. Such convergence strongly suggests that DICER1 and miR‑98‑5p may act as upstream modulators of a regulatory network that facilitates l esion establishment, survival, and progression. These insights not only deepen our understanding of endometriosis pathogenesis but also highlight potential nodes for therapeutic intervention targeting these critical pathways and biological processes. 3.4. Expression Level of hsa -miR-98-5p in Endometriosis Patients vs. Controls Quantitative analysis demonstrated a notable downregulation of hsa -miR-98-5p in ectopic endometrial tissues of endometriosis patients compared with eutopic tissues of healthy contro ls ( Figure 7). The mean expression level of hsa -miR-98-5p in the tissues of patients was reduced by 3.5 -fold (ΔΔCt = -1.81, P-value < 0.001) relative to controls. In the eutopic endometrium of patients, the expression was 2.2 -fold lower than that of contro ls (ΔΔCt = -1.14, P-value = 0.003), suggesting a systemic dysregulation that extends beyond the lesion sites. ROC curve analysis indicated that the expression of 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 182 | P a g e hsa-miR-98-5p could effectively differentiate patients from controls, achieving an AUC = 0.89 (95% CI: 0.82 –0.96), highlighting its potential as a diagnostic biomarker (At the optimal cutoff value determined by the Youden Index, this yielded a sensitivity of 85% and a specificity of 82%). Furthermore, Spearman's rank correlation analysis revealed that low levels of hsa -miR-98-5p expression were significantly associated with more advanced stages of the disease (r = -0.62, P- value = 0.001) and greater severity of dysmenorrhea (r = -0.57, P-value = 0.004) (Figure 8). No significant correlation was found with age or BMI (P-value > 0.05). Fig. 5. Analysis of Biological Processes and Gene Ontology (GO) functional enrichment related to DICER1- associated genes Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 183 | P a g e Fig. 6. DICER1 signaling pathway. Based on the KEGG online database, the diagram depicts the organized terminology of the Gene Ontology framework, displaying the particular biological terms (leaves) linked to the gene set and their connections to more general parent terms (branches). The examination reveals a notable accumulation of terms pertaining to RNA-processing complexes and nuclease functions, including the precise formation of the RISC complex, which plays a crucial role in miRNA biogenesis and RNA silencing. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 184 | P a g e Fig. 7. Differential expression and diagnostic performance of hsa -miR-98-5p in endometriosis. A) Expression analysis of hsa -miR-98-5p across three sample types: ectopic lesions (patient-derived endometrial implants outside the uterus), matched eutopic endometrium (patient -derived uterine endometrium), and normal endometrium (h ealthy control subjects). Hsa -miR-98-5p shows significant downregulation in both ectopic lesions (ΔΔCt = -1.81, P< 0.001) and eutopic endometrium from patients compared to normal healthy controls. B) The ROC curve analysis demonstrates that hsa -miR-98-5p expression effectively discriminates between endometriosis patients (combining ectopic and eutopic samples) and healthy controls, with an area under the curve (AUC) of 0.89 (95% CI: 0.82 -0.96, P-value= 0.0003). Fig. 8. Association between hsa -miR-98-5p expression and clinicopathological features in endometriosis patients.A) Comparison of hsa -miR-98-5p expression levels across endometriosis stages (I -IV) reveals a significant downregulation in ectopic lesions relative to matched eutopic tissues, with progressively lower expression observed in advanced stages (IV) compared to early stages (I -II). B) Analysis of hsa-miR-98-5p expression stratified by dysmenorrhea severity demonstrates a significant inverse correlation, where severe dysmenorrhea is associated w ith markedly reduced hsa -miR-98-5p levels in ectopic lesions compared to mild/moderate symptoms. Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 185 | P a g e 3.6. Severity analysis Considering the chronic and recurrent characteristics of endometriosis, we assessed the relationship between DICER1/hsa-miR-98- 5p expression and the severity of the disease. Patients were divided into two groups: low - severity (rASRM Stage I -II) and high -severity (rASRM Stage III -IV). The results from logistic regression analysis revealed that a one -unit decrease in ΔΔCt values of DICER1 expression was significantly associated with an elevated risk of severe disease (OR = 3.5, 95% CI: 1.8 – 6.9, P-value < 0.001). Similarly, a one -unit decrease in ΔΔCt values of hsa -miR-98-5p was correlated with a heightened risk of severe endometriosis (OR = 2.8, 95% CI: 1.5 –5.4, P- value = 0.002). The findings from the logistic regression analysis indicated that reduced levels of DICER1 and hsa -miR-98-5p expression were significantly associated with an increased risk of severe disease ( Figure 9). Furthermore, a combined model utilizing both biomarkers enhanced the predictive accuracy for disease severity (AUC = 0.82, 95% CI: 0.75–0.89). 3.5. Expression of DICER1 in endometriosis patients vs. controls Quantitative analysis revealed a significant downregulation of DICER1 mRNA levels in ectopic endometrial tissues from patients with endometriosis when compared with eutopic tissues of healthy controls ( Figure 10A). The results from qRT-PCR indicated that DICER1 mRNA levels were reduced by 4.2-fold in ectopic tissue s of patients relative to controls (ΔΔCt = −2.07, P-value < 0.001). Additionally, the eutopic endometrium of patients exhibited a 2.8 -fold reduction in DICER1 expression compared with healthy controls (ΔΔCt = −1.49, P-value = 0.002). Spearman's correlation analysis confirmed that low expression of DICER1 was significantly associated with advanced rASRM stages (r = −0.68, P-value 0.05). To explore whether hsa -miR-98-5p and DICER1 are correlated in endometriosis, we conducted a Pearson correlation analysis using miRNA and mRNA expression data from patient ectopic lesions and control eutopic endometrial samples. Our results revealed a significant positive correlation between hsa - miR-98-5p and DICER1 expression (r = 0.72, P = 0.0044). This robust association suggests a possible functional link within the miRNA biogenesis pathway. Specifically, reduced DICER1 expression may impair the prop er processing of precursor miRNAs, leading to decreased mature hsa -miR-98-5p levels. Such dysregulation could play a role in the molecular mechanisms underlying endometriosis. These findings, illustrated in Figure 10B, support the hypothesis that DICER1-mediated miRNA maturation is disrupted in ectopic tissues, potentially contributing to disease pathogenesis. These findings point to a possible functional interplay between DICER1 and hsa- miR-98-5p in endometriosis pathogenesis, potentially via shared regula tory nodes affecting miRNA processing or intersecting downstream signaling cascades. Data are expressed as mean ± SEM, derived from 55 patients and 40 healthy controls. ROC analysis for DICER1 alone yielded an AUC of 0.84 (95% CI: 0.76–0.92) in distinguishing endometriosis cases from controls. Notably, the combined DICER1/miR-98-5p signature significantly improved diagnostic performance, achieving an AUC of 0.93 (95% CI: 0.88 –0.98). Pairwise ROC comparison using DeLong’s test confirmed that this dual -marker model outperformed each individual biomarker alone, underscoring the additive value of their joint assessment. Such a synergistic relationship not only strengthens diagnostic accuracy but also hints at convergent biological pathways that may be co -opted i n disease development, warranting further mechanistic exploration. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 186 | P a g e Fig. 9. Association of DICER1 and hsa -miR-98-5p expression with endometriosis severity. A) Logistic regression analysis showing that reduced DICER1 expression is significantly associated with an increased risk of severe (Stage III/IV) endometriosis, B) Similarly, reduced hsa-miR-98-5p expression is associated with a heightened risk of severe disease (OR = 2.8, 95% CI: 1.5–5.4, P = 0.002). Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 187 | P a g e Fig. 10. A) The comparative expression lev els of DICER1 in patients versus the control group. B) Correlation analysis revealed a positive correlation between DICER1 and hsa-miR-98-5p (P = 0.0044). 4. Discussion Endometriosis is a complex, chronic gynecological condition marked by the presence of endometrial -like tissue outside the uterine cavity, impacting around 10% of women of reproductive age and resulting in pain, infertility, and a diminished quality of life [17]. Despite its widespread occurrence, the molecular mechanisms that drive its pathogenesis are not fully understood, highlighting the need for the discovery of reliable diagnostic biomarkers and therapeutic targets. Recent f indings emphasize the significant role of post - transcriptional regulation, particularly through the dysregulation of microRNA (miRNA) and disruptions in the miRNA biogenesis pathway, in the formation and advancement of endometriotic lesions [9, 18]. The claim that post-transcriptional regulation, especially through miRNA dysregulation, is crucial in the pathogenesis of endometriosis is supported by considerable recent evidence. This mechanism is integral to the disease's defining characteristics, including proliferation, inflammation, angiogenesis, and immune evasion [19]. Numerous high - throughput studies have revealed unique miRNA expression profiles in ectopic endometrium when compared with eutopic and healthy tissues. For example, members of the miR -200 family are often downregulated, which leads to increased expression of ZEB1/2 and facilitates Epithelial - Mesenchymal Transition (EMT), a vital process for lesion invasion and establishment [20]. Additionally, miR -34a and let -7b are frequently underexpressed, resulting in the upregulation of BCL -2 and MYC, which promote cell survival and proliferation in ectopic lesions [21]. Dysregulated miRNAs directly influence key pathways associated with endometriosis; for instance, the downregulation of miR -451 results in heightened MAPK signaling, which boosts cell proliferation [22]. Furthermore, the overexpression of miR -21-5p targets PTEN and PDCD4, thereby promoting survival and inhibiting apoptosis in endometriotic cells and the suppression of miR -126 contributes to angiogenesis through the upregulation of VEGFA [23]. A case -control study revealed differences in miR -125b levels between eutopic and ectopic endometrium in patients with endometriosis compared with healthy controls. It ha s also been suggested that the 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 188 | P a g e increased activity of miR-125b interferes with TP53 expression, inhibiting apoptosis [24]. Another study identified 22 miRNAs associated with endometriosis through microarray analysis of ectopic and euto pic endometrial tissues. Among these, 14 miRNAs were found to be up -regulated and 8 miRNAs were down -regulated [25]. Additionally, another study identified 10 miRNAs that were up-regulated in cases of endometriosis, and 12 miRNAs were down -regulated compared with normal endometrial tissue [26]. The core machinery responsible for miRNA processing, which includes Drosha, Dicer, and Argonaute proteins, is often disrupted in cases of endometriosis. A decrease in DICER1 expression has been observed in ectopic stromal cells, resulting in a widespread impairment of mature miRNA biosynthesis. This situation fosters an environment conducive to the overexpression of oncogenes and inflammatory mediators [27]. Epigenetic changes (such as promoter hypermethylation of DICER1) and inflammatory cytokines (including TNF -α and IL -1β) can inhibit the expression and function of miRNA -processing enzymes, further worsening miRNA dysregulation. DICER1 is central to this mechanism, being a crucial ri bonuclease that facilitates mature miRNA processing, and its altered expression has been linked to gynecological disorders [28]. At the same time, miR-98-5p, a member of the let -7 family known for its roles in regulating inflammation, cell proliferation, and invasion in various diseases, has surfaced as a potential regulator in endometriosis. Additionally, miR - 98 has been reported to function as a tumor suppressor by directly targeting genes that promote tumorigenesis. Research has shown that miR -98 significantly influences cancer cell proliferation, apoptosis, and the regulation of the cell cycle. Its interaction with the cell cycle machinery can determine cell fate; for example, studies in cervical cancer indicate that overexpression of miR -98 can lead to G1 cell cycle arrest. Additionally, miR - 98 plays a crucial role in metastasis and angiogenesis, which are vital p rocesses for cancer spread and growth [18]. Nevertheless, the functional interplay between DICER1 and miR-98-5p, along with their combined potential as diagnostic markers in matched ectopic and eutopic endometrial tissues, has yet to be investigated. While previous studies, such as Rekker et al. have identified various miRNA biomarkers, often in circulation [29], our work uniquely focuses on the tissue - specific dysregulation of the DICER1-miR-98- 5p axis within the lesion microenvironment itself, providing direct insight into the disease mechanism and a highly specific tissue -based diagnostic signature. In this study, we investigated the expression and clinical relevance of DICER1 and miR-98-5p, aiming to elucid ate their roles in the development of endometriosis and evaluate their potential as a new biomarker panel. We present new clinical evidence indicating that the coordinated downregulation of the ribonuclease DICER1 and its possible regulatory target, hsa-miR-98- 5p, represents a crucial molecular event in the formation and persistence of endometriotic lesions. Our results, obtained from the examination of matched eutopic and ectopic endometrial tissues, establish this axis not only as a significant factor in the molecular pathology of the disease but also emphasize its considerable potential as a reliable diagnostic biomarker panel. This is consistent with the emerging understanding that disruptions in the miRNA biogenesis machinery play a vital role in gyneco logical disorders [30], and further expands this concept by pinpointing a specific miRNA - processor partnership pertinent to endometriosis. The findings of this study reveal that the coordinated downregulation of DICER1 and hsa-miR-98-5p is a piv otal event in endometriosis pathogenesis. This alignment is not coincidental but reflects a self -reinforcing pathogenic loop that promotes lesion survival and progression, supported by recent molecular studies [31]. Reduced DICER1 expression, a consistent feature in our ectopic tissue samples, compromises the processing of pre -miRNAs into mature miRNAs. This creates a permissive environment for the unchecked expression of genes promoting invasion, inflammation, and survival. This is consistent with studies by Li et al., who demonstrated that DICER1 downregulation in endometrial stromal cells leads to a global Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 189 | P a g e impairment of miRNA biogenesis, directly contributing to a pro -endometriotic transcriptomic landscape [32]. The specific downregulation of hsa -miR-98-5p, a member of the tumor -suppressive let -7 family, is particularly significant. DICER1 is essential for the generation of mature let -7 miRNAs. Our correlation analysis supports that low DICER1 levels directly contribute to reduced miR-98- 5p maturation. Sergi et al. stated that while DICER1 is crucial for normal female reproductive tract development and function , its somatic dysregulation in adult tissues is increasingly linked to pathologies like endometriosis [33]. Nothnick states that while many miRNAs have been proposed as biomarkers, the field is moving towards multi- marker panels and understanding mechanistic partnerships (like the one between a processor and a miRNA) to improve diagnostic specificity and accuracy [34]. As reviewed by Zafari et al., the loss of let -7 family members is a recurring issue in endometriosis, resulting in the derepression of their oncogenic and inflammatory targets [35]. The concurrent loss of this regulator - effector pair has cumulative effects: miR-98-5p directly targets IL -6 and TGF -βR1, which are essential drivers of proliferation/invasion and epithelial-mesenchymal transition (EMT). The derepression caused by low lev els of miR-98- 5p promotes lesion establishment, angiogenesis, and regulates VEGFA expression [36]. Its absence encourages the vascularization of lesions, a vital step for their persistence, as emphasized in studies on tumor metabolism by Hazari et al. [13]. Our research reveals a notable downregulation of miR-98-5p in endometriotic lesions, which holds significant functional implications. The reduction of this essential regulatory miRNA is not merely a passive outcome but rather an active contributor to disease pathogenesis , as it results in the derepression of a network of pro-endometriosis target genes. In particular, our findings align with existing literature indicating that miR-98-5p directly targets and inhibits the expression of: HMGA2, a gene often overexpressed in e ndometriosis that encourages cell proliferation and survival [37], IL -6, a key pro -inflammatory cytokine that supports the chronic inflammatory microenvironment typical of the disease [38], VEGFA, a principal regulator of angiogenesis necessary for the vascularization and growth of ectopic implants [39], E2F1 and CCND1, vital regulators of cell cycle progression whose dysregulation results in uncontrolled proliferation [40]. Consequently, the noted decline in miR-98-5p expression, p otentially worsened by the simultaneous downregulation of DICER1, establishes a permissive environment where these oncogenic, inflammatory, and angiogenic pathways become excessively active. This multi-target mechanism elucidates how the loss of a single m iRNA can collectively drive the fundamental processes of endometriosis progression: proliferation, inflammation, and neovascularization. Thus, our data position the miR-98-5p node as a pivotal regulatory hub in endometriosis, whose disruption has far-reaching effects on the cellular transcriptome. The DICER1/miR-98-5p axis may affect the expression of immune -modulating proteins such as PD -L1 and create an immunosuppressive environment that allows lesions to escape immune surveillance [41]. This coordinated downregulation offers a robust multi-marker diagnostic signature. The strong correlation observed between their expression levels and disease severity (rASRM stage) indicates that evaluating both molecules could enhance diagnostic accuracy compared with single markers, a strategy supported by Rekker et al. in their research on miRNA panels [29]. Moreover, therapeutic approaches aimed at restoring miR-98-5p function (for instance, through the use of miRNA mimics) or stabilizing DICER1 expression could disrupt this pathogenic cycle, presenting a novel targeted treatment strategy. MiR-98 has emerged as a significant factor in ovarian cancer, with its expression levels influencing various oncogenic pathwa ys and patient outcomes. Research has shown that miR-98-5p is enriched in cisplatin -resistant epithelial ovarian cancer (EOC) cells [13]. This enrichment promotes cisplatin resistance by inhibiting the biogenesis of miR -152 through the targeting of DICER1, which is associated with poor outcomes in EOC patients. Among a panel of miRNAs, miR-98-5p has been identified as a biomarker for resistance to 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 190 | P a g e platinum-based chemotherapy in high -grade serous ovarian cancer (HGSC) [42]. Furthermore, when examining the transition of endometrial cells, abnormal expression of miR-98 has been linked to the progression into cancerous states. Studies have shown that miR-98-5p is often downregulated in ectopic endometrial tissues compared w ith eutopic tissues [35]. This downregulation may contribute to the increased proliferation and survival of endometrial cells outside the uterus, which is a hallmark of endometriosis. The varied roles of miR-98-5p in both ovarian and endometrial cancers, including its influence on disea se progression and chemoresistance, highlight its potential as a valuable biomarker in women's health disorders. Given its wide -ranging effects, there is an urgent need for further research to optimize its application in therapeutic strategies for endometriosis. Several limitations of this study must be recognized. Firstly, our sample size (n=30 patients with endometriosis, n=35 controls), although adequate for initial discovery, may restrict the statistical power for subgroup analyses and multivariate adj ustments. Secondly, the single -center design at Shahid Sadoughi Hospital, while providing consistent surgical and laboratory protocols, may influence the generalizability of our results to larger populations with varying ethnic and demographic characterist ics. Thirdly, this study concentrated solely on tissue -based biomarkers without examining circulating levels in serum or plasma, which would be essential for the development of non -invasive diagnostic tests. Most critically, our study offers correlative ev idence but lacks functional validation experiments; the mechanistic link between DICER1 downregulation and miR-98-5p reduction has yet to be experimentally confirmed through in vitro or in vivo models. Future research with larger, multi -center cohorts and functional experiments is required to validate these findings and establish causal mechanisms. 5. Conclusion This study identifies the DICER1/miR-98- 5p axis as an active contributor to endometriosis, where its dysregulation promotes a lesion -permissive microenvironment. Under normal conditions, miR-98-5p fine-tunes cellular growth, differentiation, and apoptosis by targeting key mRNAs involved in these processes. We found significant disruption of this regulatory axis in endometriosis, suggesting its dual r ole as a diagnostic biomarker and therapeutic target. The differential expression of miR-98-5p and DICER1 in ectopic versus eutopic tissues underscores their clinical potential. Further research is needed to fully elucidate their pathophysiological roles a nd translational applications. Conflict of Interests The authors declare no conflict of interest. Ethics approval and consent to participate The study was conducted in complete compliance with the ethical standards outlined in the Declaration of Helsinki a nd was approved by the Research Ethics Committee of Shahid Sadoughi University of Medical Sciences, Iran (Approval Code: IR.YAZD.REC.1402.002). Before participation, written informed consent was obtained from all individuals. The study protocol emphasized participant autonomy, confidentiality, and the right to withdraw at any stage without consequence. All collected data were anonymized and securely stored in accordance with international standards for biomedical data protection, including encryption and ac cess restrictions, to ensure participant privacy. Consent for publication The authors read and approved the final manuscript for publication. Informed Consent The authors declare not used any patients in this research. Availability of data and material The data that support the findings of this study are available from the corresponding author upon reasonable request. Authors' contributions Conceptualization: Mehri Khatami. Data curation: Mohammad Mehdi Heidari. Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 191 | P a g e Formal analysis: Mohammad Mehdi Heidari. Investigation: Mahdieh Azizi Panah. Methodology: Mohammad Mehdi Heidari. Project administration: Mahdieh Azizi Panah. Software: Mahdieh Azizi Panah. Resources: All authors. Supervision: Mehri Khatami. Validation: Mojgan Hajisafari Tafti. Visualization: Mojgan Hajisafari Tafti. Writing–original draft: Mehri Khatami. Writing–reviewing & editing: All authors. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Acknowledgments The authors t hank all the patients for providing tissue samples. The Yazd University Human Research Committee approved the study. The author also sincerely appreciate our colleagues for their constructive comments and contributions.

1. Ochoa Bernal MA, Fazleabas AT (2024) The known, the unknown and the future of the pathophysiology of endometriosis. International Journal of molecular sciences 25 (11): 5815. doi: https://doi.org/10.3390/ijms25115815 2. Chen F, Zhu M, Li W (2024) Advanc es in research on malignant transformation of endometriosis-associated ovarian cancer. Frontiers in Oncology Volume 14 - 2024: 1475231. doi: https://doi.org/10.3389/fonc.2024.14752 31 3. Santulli P, Bourdon M, Desportes C, Maignien C, Pocate -Cheriet K, Patr at C, Marcellin L, Chapron C (2024) Assessment of the pelvic pain experienced by infertile women is of prime importance for diagnosing endometriosis. Journal of Minimally Invasive Gynecology 31 (11): 943-950. e941. doi: http://doi.org/https://doi.org/10.1016/j.j mig.2024.07.010. 4. Marquardt RM, Tran DN, Lessey BA, Rahman MS, Jeong J -W (2023) Epigenetic dysregulation in endometriosis: implications for pathophysiology and therapeutics. Endocrine reviews 44 (6): 1074-1095. doi: http://doi.org/10.1210/endrev/bnad020. 5. An Y, Feng Q, Jia L, Sha X, Zhang T, Lu L, Wang R, Bai B (2025) Present progress in biomarker discovery of endometrial cancer by multi -omics approaches. Clinical Proteomics 22 (1): 15. doi: https://doi.org/10.1186/s12014-025- 09528-6 6. Alotaibi F T (2025) Pathophysiology of Endometriosis: Insights from Immunohistochemical Analysis of Ectopic and Eutopic Tissues. International Journal of Molecular Sciences 26 (13): 5998. doi: https://doi.org/10.3390/ijms26135998 7. Eslammanesh T, Mirshekari A, Dahma rdeh N, Ghafari M, Mahmoodi F, Jahantigh M, Mirzaei AR, Fazeli -Nasab B (2025) Mechanisms of miRNAs and their expression in gastric cancer. Archives of Razi Institute 80 (1): 217 -224. doi: https://doi.org/10.32592/ari.2025.80.1.21 7 8. Ghaffari M, Fazeli F, Mirshekari A, Rashki Ghalenoo S, Mirzaei AR, Fazeli -Nasab B (2025) Analysis of miRNAs and Genes Related to Cardiovascular and Neurological Diseases in Cicer arietinum L. Journal of Medicinal plants and By -Products 14 (2): 177-188. doi: https://doi.org/10.22034/jmpb.2024.366 716.1740 9. Khatami M, Heidari MM, Hajisafari Tafti M (2025) Exploring the pathologic role of microRNAs as diagnostic and therapeutic markers in endometriosis: A narrative review. Journal of Translational Medical Research 32 (2): 79-97. doi: http://doi.org/10.61882/JBUMS.32.2.79 10. Kluz N, Kowalczyk E, Wasilewska M, Gil - Kulik P (2024) Diagnostic value and molecular function of microRNAs in endometrial diseases: a systematic review. Cancers 16 (13): 2416. doi: https://doi.org/10.3390/cancers1613241 6 11. Shokrnejad‐namin T, Farzizadeh N, Najmi Z, Amoozgar M, Hariri A, Amini E, Khosravi A, Zarrabi A (2026) Evaluating the diagnostic potential of CA‐125 and miRNA levels in endometriosis: A narrative review. 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 192 | P a g e International Journal of Gyn ecology & Obstetrics 172 (3): 1392 -1429. doi: https://doi.org/10.1002/ijgo.70554 12. Zhang M, Xu T, Tong D, Li S, Yu X, Liu B, Jiang L, Liu K (2023) Research advances in endometriosis-related signaling pathways: a review. Biomedicine & Pharmacotherapy 164: 114909. doi: http://doi.org/https://doi.org/10.1016/j.b iopha.2023.114909. 13. Hazari V, Samali SA, Izadpanahi P, Mollaei H, Sadri F, Rezaei Z (2024) MicroRNA -98: the multifaceted regulator in human cancer progression and therapy. Cancer Cell International 24 (1): 209. doi: https://doi.org/10.1186/s12935-024- 03386-2 14. Akhlaghipour I, Moghbeli M (2024) MicroRNA-98 as a novel diagnostic marker and therapeutic target in cancer patients. Discover Oncology 15 (1): 385. doi: https://doi.org/10.1007/s12672-024- 01270-z 15. Wang Y, Bao W, Liu Y, Wang S, Xu S, Li X, Li Y, Wu S (2018) miR-98-5p contributes to cisplatin resistance in epithelial ovarian cancer by suppressing miR -152 biogenesis via targeting DICER1. Cell death & disease 9 (5): 447. doi: https://doi.org/10.1038/s41419-018- 0390-7 16. Jansen FA, Bakhuizen J, Kester L, de Krijger RR (2025) DICER1 Syndrome: What Do We Know of the Pathogenetic Mechanisms? Cancers 17 (17): 2885. doi: https://doi.org/10.3390/cancers1717288 5 17. Chen Y, Waseem S, Luo L (2025) Adv ances in the diagnosis and management of endometriosis: A comprehensive review. Pathology-Research and Practice 266: 155813. doi: http://doi.org/https://doi.org/10.1016/j.p rp.2025.155813. 18. Hon J -X, Wahab NA, Karim AKA, Mokhtar NM, Mokhtar MH (2023) Micr oRNAs in endometriosis: insights into inflammation and progesterone resistance. International journal of molecular sciences 24 (19): 15001. doi: http://doi.org/10.3390/ijms241915001. 19. Pant A, Moar K, Arora TK, Dakal TC, Ranga V, Sharma NK, Maurya PK (20 25) Deciphering the role of circulating miRNAs in the etiology and pathophysiology of endometriosis: an updated compiled review. Experimental cell research 446 (2): 114482. doi: http://doi.org/https://doi.org/10.1016/j.y excr.2025.114482. 20. Hagh YN, Ahmad ifard M, Esmaelzadeh S, Abbaszadeh S, Shokrzadeh N (2025) Decreased expression of miR -200a and miR-223-3p in endometriosis during the secretory phase of menstrual cycle: Insights from a case -control study on molecular biomarkers and disease -related infertility. International Journal of Reproductive Biomedicine 22 (12): 1003. doi: https://doi.org/10.18502/ijrm.v22i12.180 66 21. Vanhie A, Caron E, Vermeersch E, O D, Tomassetti C, Meuleman C, Mestdagh P, D’Hooghe TM (2024) Circulating microRNAs as non -invasive biomarkers in endometriosis diagnosis —a systematic review. Biomedicines 12 (4): 888. doi: https://doi.org/10.3390/biomedicines120 40888 22. Li X, Zhang W, Fu J, Xu Y, Gu R, Qu R, Li L, Sun Y, Sun X (2019) MicroRNA -451 is downregulated in the follicular flui d of women with endometriosis and influences mouse and human embryonic potential. Reproductive Biology and Endocrinology 17 (1): 96. doi: https://doi.org/10.1186/s12958-019- 0538-z 23. Mahmoud M, WalyEldeen AA, Samie MA, Sadek AM, Elakhras S, Samir M, Ahmed O, Sayed RMS, Baiomy AA, Ibrahim SA (2025) Overexpression of miR-21-5p as a potential pathogenesis marker for ovarian endometriosis. The Journal of Basic and Applied Zoology 86 (1): 1. doi: https://doi.org/10.1186/s41936-024- 00414-5 24. Szubert M, Nowak -Glück A, Domańska - Senderowska D, Szymańska B, Sowa P, Rycerz A, Wilczyński JR (2023) miRNA expression profiles in ovarian endometriosis and two types of ovarian cancer—endometriosis-associated ovarian cancer and high -grade ovarian cancer. International Journal of Molecular Sciences 24 (24): 17470. doi: https://doi.org/10.3390/ijms242417470 Cell. Mol. Biomed. Rep. 2026, 6(2): 170-194 193 | P a g e 25. Ohlsson Teague EMC, Van der Hoek KH, Van der Hoek MB, Perry N, Wagaarachchi P, Robertson SA, Print CG, Hull LM (2009) MicroRNA-regulated pathways associated with endom etriosis. Molecular endocrinology 23 (2): 265 -275. doi: https://doi.org/10.1210/me.2008-0387 26. Vanhie A, O D, Peterse D, Beckers A, Cuéllar A, Fassbender A, Meuleman C, Mestdagh P, D’Hooghe T (2019) Plasma miRNAs as biomarkers for endometriosis. Human Re production 34 (9): 1650 -1660. doi: https://doi.org/10.1093/humrep/dez116 27. Tong X, Duan Q, Ge M, Shang X, Zhang X, Chen D, He L (2025) DICER1 Mutations Exhibit a Distinctive Immune Characteristics With Enhanced Immune Checkpoint Inhibitor Efficacy in Ute rine Corpus Endometrial Carcinoma. Clinical Oncology 44: 103883. doi: https://doi.org/10.1016/j.clon.2025.1038 83 28. Bhingardeve S, Sagvekar P, Mukherjee S (2025) Altered DNA methylation and miRNA expression: epi -marks for elucidating the pathophysiology o f PCOS. Reproductive biomedicine online 51 (1): 104838. doi: https://doi.org/10.1016/j.rbmo.2025.104 838 29. Rekker K, Saare M, Roost AM, Kaart T, Soritsa D, Karro H, Soritsa A, Simón C, Salumets A, Peters M (2015) Circulating miR-200–family micro -RNAs have altered plasma levels in patients with endometriosis and vary with blood collection time. Fertility and sterility 104 (4): 938 -946. e932. doi: https://doi.org/10.1016/j.fertnstert.2015. 06.029 30. Bjorkman S, Taylor HS (2019) MicroRNAs in endometriosis: bi ological function and emerging biomarker candidates. Biology of reproduction 101 (6): 1167 -1178. doi: https://doi.org/10.1093/biolre/ioz014 31. Azam INA, Wahab NA, Mokhtar MH, Shafiee MN, Mokhtar NM (2022) Roles of microRNAs in Regulating Apoptosis in the Pathogenesis of Endometriosis. Life 12 (9): 1321. doi: https://doi.org/10.3390/life12091321 32. Li B, Lu W, Qu J, Zhang Y, Wan X (2017) DICER1 regulates endometrial carcinoma invasion via histone acetylation and methylation. Journal of Cancer 8 (6): 933. doi: https://doi.org/10.7150/jca.17435 33. Sergi CM, Minervini F (2025) DICER1: The Argonaute Endonuclease Family Member and Its Role in Pediatric and Youth Pathology. Biology 14 (1): 93. doi: https://doi.org/10.3390/biology1401009 3 34. Nothnick WB MicroRNA s and endometriosis: distinguishing drivers from passengers in disease pathogenesis. In: Seminars in reproductive medicine, 2017. vol 02. Thieme Medical Publishers, pp 173 - 180. doi: https://doi.org/10.1055/s-0037- 1599089 35. Zafari N, Tarafdari AM, Izadi P , Noruzinia M, Yekaninejad MS, Bahramy A, Mohebalian A (2021) A panel of plasma miRNAs 199b-3p, 224-5p and Let-7d-3p as non-invasive diagnostic biomarkers for endometriosis. Reproductive Sciences 28 (4): 991 -999. doi: https://doi.org/10.1007/s43032-020- 00415-z 36. Wang J, Xiang H, Lu Y, Wu T (2021) Role and clinical significance of TGF -β1 and TGF-βR1 in malignant tumors. International journal of molecular medicine 47 (4): 55. doi: https://doi.org/10.3892/ijmm.2021.4888 37. Jiang P, Yu J, Zheng Y, Tian C, Tu Y, Gong C, Yu H, Luo Y, Hu Z (2025) Prognostic significance and immune infiltration analysis of HMGA2 in endometrial cancer. Frontiers in Immunology 16: 1559278. doi: https://doi.org/10.3389/fimmu.2025.155 9278 38. Hua M, Wang Y, Yao J, Zhu Z, Liu X, Meng F, Yu S (2025) Analysis of inflammatory biomarkers IL -6, vascular endothelial growth factor and matrix metalloproteinases-9 expression in endometriosis. SAGE Open Medicine 13: 20503121251321625. doi: https://doi.org/10.1177/2050312125132 1625 39. Englert-Golon M, Tokłowicz M, Żbikowska A, Sajdak S, Kotwicka M, Jagodziński P, Pławski A, Andrusiewicz M (2026) HIF1A, EPAS1, and VEGFA: angiogenesis and hypoxia-related gene expression in endometrium and endometrial epithelial tumors. Journal of Applied Genetics 67 (1): 2026, 6(2): 170-194 Cell. Mol. Biomed. Rep. 194 | P a g e 139-153. doi: https://doi.org/10.1007/s13353-025- 00939-7 40. Szymański M, Jerka D, Bonowicz K, Antosik P, Gagat M (2025) Assessment of Cyclin D1 Expression: Prognostic Value and Functional Insights in Endometrial Cancer: In Silico Study. International Journal of Molecular Sciences 26 (3): 890. doi: https://doi.org/10.3390/ijms26030890 41. Zare E, Yaghoubi SM, Khoshnazar M, Jafari Dargahlou S, Machhar JS, Zheng Z, Duijf PH, Mansoori B (2025) MicroRNAs in cancer immunology: master regulators of the tumor microenvironment and immune evasion, with therapeutic potential. Cancers 17 (13): 2172. doi: https://doi.org/10.3390/cancers1713217 2 42. Nunes M, Bartosch C, Abreu MH, Richardson A, Almeida R, Ricardo S (2024) Deciphering th e molecular mechanisms behind drug resistance in ovarian cancer to unlock efficient treatment options. Cells 13 (9): 786. doi: https://doi.org/10.3390/cells13090786 How to Cite This Article: Download citation: Copyright © 2026 by the author (s). This is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/) Khatami M, Azizi Panah M, Heidari MM, Hajisafari Tafti M (2026) Differential expres sion of miR-98-5p and DICER1 in eutopic versus ectopic endometrium: a diagnostic biomarker signature for endometriosis. Cellular, Molecular and Biomedical Reports 6 (2): 170 -194. doi: 10.55705/cmbr.2026.550859.1337 RIS; EndNote; Mendeley; BibTeX; APA; MLA ;HARVARD; CHICAGO; VANCOUVER