Prognostic Significance of RBM3 Expression in Epithelial Ovarian Cancer: A Tissue Microarray-Based Study

Background/Objectives: RNA-binding motif protein 3 (RBM3) is a cold-shock protein associated with a favorable prognosis in various malignancies. However, its role in epithelial ovarian cancer (OC) remains unclear. This study aimed to evaluate the prognostic significance of RBM3 expression in OC and its association with clinicopathological features. Methods: We retrospectively analyzed 183 cases of OC. Tissue microarrays were constructed using paired 2 mm tumor cores, and RBM3 expression was assessed by immunohistochemistry. Nuclear staining was semi-quantitatively scored based on intensity and proportion, generating a nuclear score (NS). Cases were classified as high (NS > 1) or low (NS ≤ 1) expression. Associations with clinicopathological parameters and survival outcomes were analyzed using chi-square tests, Kaplan-Meier survival curves, and Cox regression models. Results: High RBM3 expression was observed in 51.4% of cases and was significantly associated with favorable histologic subtypes (mucinous, endometrioid, clear cell), early International Federation of Gynecology and Obstetrics (FIGO) stage, and the absence of distant metastasis. Subgroup survival analyses stratified by histologic subtype revealed no significant differences in survival outcomes. RBM3 expression was correlated with prolonged disease-free and overall survival, although it did not retain significance in multivariate analysis. Conclusions: RBM3 expression is strongly associated with favorable pathological features in epithelial ovarian cancer. Although not an independent prognostic marker, RBM3 may serve as a complementary biomarker for risk stratification and prognosis in clinical practice.