Commentary on "Biallelic inactivation of BRCA2 in platinum-sensitive metastatic castration-resistant prostate cancer". Cheng HH, Pritchard CC, Boyd T, Nelson PS, Montgomery B. Eur Urol. Jun 2016;69(6):992-5.

Understanding the molecular underpinnings of sensitivity to specific therapies will advance the goal of precision medicine in prostate cancer (PCa). We identified 3 patients with metastatic castration-resistant PCa (mCRPC) who achieved an exceptional response to platinum chemotherapy (not first-line treatment for PCa), despite disease progression on prior standard therapies. Using targeted next-generation sequencing on the primary and metastatic tumors, we found that all 3 patients had biallelic inactivation of BRCA2, a tumor suppressor gene critical for homologous DNA repair. Notably, 2 had germline BRCA2 mutations, including a patient without compelling family history who was diagnosed at age 66 year. The third patient had somatic BRCA2 homozygous copy loss. Biallelic BRCA2 inactivation in mCRPC warrants further exploration as a predictive biomarker for sensitivity to platinum chemotherapy.