Introduction/Background Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological malignancies. Deficiency in BRCA1 function is associated with increased tumor sensitivity to platinum-based chemotherapy. However, the efficacy of immunohistochemistry (IHC) to identify BRCA1 deficiency is not well established. The aim of this study was to synthesize the evidence on the association of BRCA1 expression by IHC with the prognosis of women with EOC.

Methodology Using the concepts ovarian neoplasms and IHC testing for BRCA, published titles were systematically searched in four databases (Embase, PubMed, Web of Science, and Scopus). The study was conducted using the PRISMA statement. Meta-analyses for the Hazard Ratios (HR) of overall survival (OS) and progression-free survival (PFS) were calculated with the package ‘meta’ in the R environment.

Results Fourteen studies comprising 2,071 EOC cases were included. Low IHC expression of BRCA1 was reported in 48.5% of cases. The low expression of BRCA1 was associated with improved OS (HR=0.64; 95% CI 0.53–0.76) and with improved PFS (HR=0.75; 95% CI 0.59–0.94). The heterogeneity was high (I²=72%) among the studies on OS and moderate (I²=61%) among PFS studies.

Conclusion Low expression of BRCA1, identified by IHC, was consistently associated with the overall and progression-free survival in EOC. This find may be important in clinical practice, especially with the popularization of the use of PARP inhibition as part of EOC treatment. However, well-designed, prospective studies are still needed to confirm these results.

Disclosure Nothing to disclose.