The aim of the study was to evaluate the expression and exploratory diagnostic potential of selected microRNAs (miRNAs) in ovarian cancer tissue compared with benign ovarian lesions. Tissue samples from 24 patients with epithelial ovarian cancer and 22 patients with benign ovarian lesions were analyzed by quantitative real-time polymerase chain reaction. Ten candidate miRNAs were assessed; six met the predefined detection criteria and were retained for analysis. Group differences were tested with non-parametric methods and false discovery rate (FDR) correction. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis, and multivariable logistic regression adjusted for age and menopausal status. Survival analyses were exploratory. miR-381-3p was downregulated, whereas miR-582-5p and miR-425-5p were upregulated in ovarian cancer compared with benign ovarian lesions; all three differences remained significant after FDR correction. miR-425-5p showed the highest individual diagnostic accuracy (AUC = 0.854) and remained associated with ovarian cancer after adjustment for age and menopausal status (OR = 7.84; 95% CI = 2.05–29.97; p = 0.003). This association was also retained in Firth penalized logistic regression. An exploratory three-miRNA panel achieved an apparent AUC of 0.858 but did not significantly outperform miR-425-5p alone (DeLong p = 0.596); its optimism-corrected bootstrap AUC was 0.822. No significant associations with survival were identified. miR-425-5p was the strongest candidate biomarker in this exploratory tissue-based study. Independent validation is required before clinical application.

Epigenetic dysregulation is increasingly recognized as an important contributor to ovarian carcinogenesis, and may provide novel diagnostic and prognostic biomarkers. This study evaluated DNA methylation and mRNA expression of SEPT9 and AKR1B1 in ovarian cancer and benign ovarian lesions and assessed their clinical significance. Tissue samples were obtained from 27 patients with ovarian cancer and 29 patients with benign ovarian lesions. DNA methylation was analyzed by pyrosequencing and mRNA expression by real-time PCR. Associations with clinicopathological variables, serum CA125 and HE4 concentrations, diagnostic performance, and survival outcomes were evaluated. Receiver operating characteristic (ROC) analysis, multivariable logistic regression, Kaplan–Meier analysis, and Cox regression models were performed. Multiple testing was controlled using the Benjamini–Hochberg false discovery rate procedure. Ovarian cancer tissues demonstrated significantly lower SEPT9 methylation (q = 0.008), higher AKR1B1 methylation (q = 0.0008), and lower AKR1B1 mRNA expression (q = 0.035) compared with benign ovarian lesions. SEPT9 methylation showed the highest diagnostic accuracy (AUC = 0.741). Both SEPT9 methylation (OR = 0.92, p = 0.014) and AKR1B1 methylation (OR = 9.69, p = 0.008) remained independently associated with ovarian cancer after adjustment for age and menopausal status. Low AKR1B1 mRNA expression was associated with shorter progression-free survival (p = 0.0007). These findings indicate that SEPT9 methylation and AKR1B1 dysregulation are associated with ovarian cancer. SEPT9 methylation demonstrated the best discriminative ability among the evaluated biomarkers. Further validation in larger independent cohorts is warranted.