The Performance of BRCA1 Immunohistochemistry for Detecting Germline, Somatic, and Epigenetic BRCA1 Loss in High-Grade Serous Ovarian Cancer

Background BRCA1 expression can be lost by a variety of mechanisms including germline or somatic mutation and promotor hypermethylation. Given the potential importance of BRCA1 loss as a predictive and prognostic biomarker in high-grade serous ovarian cancer, we sought to evaluate the utility of BRCA1 immunohistochemistry (IHC) in screening for BRCA1 loss by germline, somatic, and epigenetic mechanisms.