PARP1 and cancer: On the other hand, the discovery of synthetic lethality induced by PARP inhibitors (PARPi) in BRCA-mutated cancers (124, 125) and the recognition that approximately half of HGSOC tumors harbor genomic features of HRD (46) led to the fervent investigation of PARPi (126–128), resulting in the approval of three agents (olaparib, rucaparib, and niraparib).