Some patients with metastatic castration-resistant prostate cancer (mCRPC) possess germline or acquired defects in the DNA damage repair (DDR) genes BRCA1 and BRCA2. Tumors with BRCA mutations exhibit sensitivity to poly-ADP ribose polymerase inhibitors (PARPi) such as olaparib and rucaparib. As a result, molecular diagnostic testing to identify patients with BRCA mutations eligible for the PARPi therapy has become an integral component of managing patients with mCRPC. There are …