Four PARP inhibitors, including olaparib, rucaparib, niraparib, and talazoparib, have been approved by the FDA to treat metastatic breast cancer, ovarian cancer, fallopian tube cancer, prostate cancer, and primary peritoneal cancer harboring deleterious germline mutations in BRCA1/2 or with platinum-sensitivity properties (54). The gene discussed is PARP1; the disease is ovarian cancer.