Immunohistochemical Expression of Estrogen Receptor, Progesterone Receptor, Human Epidermal Growth Factor Receptor Type 2/neu, and S-100 in Epithelial Ovarian Tumors: Correlation with Clinicopathological Parameters

Abstract Background: Ovarian cancer is one of the most lethal gynecologic malignancies worldwide. More than 90% of ovarian cancers arise from the surface epithelium and are collectively termed epithelial ovarian tumors (EOTs). Recently, molecular markers such as Human Epidermal Growth Factor Receptor 2, Estrogen Receptor, Progesterone Receptor, and S100 protein have gained attention for their potential role in improving diagnosis, prognosis, and targeted therapy in ovarian tumors. Objectives: To evaluate the expression of ER, PR, HER2/neu, and S100 in epithelial ovarian tumors and to correlate their expression with histological subtype, tumor grade, and clinical characteristics. Materials and Methods: A prospective study was conducted on 50 histopathologically confirmed cases of epithelial ovarian tumors over a period of 18 months in the Department of Pathology at Rajendra Institute of Medical Sciences, Ranchi. Immunohistochemical analysis for ER, PR, HER2/neu, and S100 was performed on tumor tissue sections. Statistical analysis was carried out using Chi-square and Fisher’s exact test, and a p-value <0.05 was considered statistically significant. Results: Among the 50 cases studied, 33% were benign, 12% were borderline, and 56% were malignant tumors. The most common histological subtype was serous tumors (62%). ER and PR positivity was highest in malignant tumors, with ER expressed in 78.57% and PR in 67.86% of cases. HER2/neu expression was observed exclusively in malignant tumors (53.57%) and showed the highest positivity in Grade III tumors (82.35%). S100 expression was significantly associated with Grade III tumors and clinical features such as ascites and weight loss. It was also more frequently expressed in serous tumors (74.19%). Conclusion: The expression patterns of ER, PR, HER2/neu, and S100 vary significantly among epithelial ovarian tumor subtypes and tumor grades. Immunohistochemical evaluation of these markers has potential prognostic value and may help guide targeted therapeutic strategies, particularly in resource-limited settings. Further studies with larger sample sizes are required to validate these findings and strengthen their clinical applicability.