BRCA1 and breast cancer: There are currently four PARP inhibitors (Olaparib, Rucaparib, Niraparib, and Talazoparib) approved by the FDA for the treatment of advanced ovarian and breast cancers with BRCA1/2 deficiency [23,24], and three PARP inhibitors (Veliparib, Pamiparib, and Fluzoparib) are currently under clinical trials for evaluation [25].