Evaluation of Mismatch Repair (MMR) and Breast Cancer-1 (BRCA-1) Statuses in Epithelial Ovarian Cancer

This study aims to evaluate the expression of BRCA1 and MMR proteins using immunohistochemistry (IHC) in epithelial ovarian cancers and to explore their clinicopathological correlations.

IHC was performed and interpreted for BRCA1, MLH1, MSH2, MSH6, and PMS2. The results were then compared with clinical and pathological variables.

Over a period of 19 months, 508 specimens containing ovarian tissue were received, either as part of a hysterectomy or as isolated samples for various indications. Among these, 24.01% (122/508) showed invasive epithelial ovarian cancer. Of these, 49 resection specimens had sufficient tumor tissue for detailed immunohistochemistry (IHC) analysis and were included in the study. Among the evaluated cases, 51% (25/49) of invasive epithelial ovarian cancers exhibited deficient mismatch repair (dMMR). No significant correlation was observed between dMMR and pMMR with respect to grade, cellularity, and high-grade features. Patients with dMMR showed better survival, which may be due to improved response to chemotherapy in these cases. Total loss of BRCA1 was seen in 36.7% (18/49) of cases. BRCA1 loss was associated with poor predictive factors but had better prognosis. Loss of BRCA1 was associated with aggressive tumors but had better response to chemotherapy. Both MMR and BRCA1 were independent variables. The overall survival of our patient population with epithelial ovarian cancer was 86.8%.

A significant number of patients displayed dMMR and BRCA1 loss by IHC. These patients may benefit from targeted therapy, and IHC may serve as an acceptable technique for each evaluation.