It has been disclosed that in BRCA1/2-mutant cancer cells, inhibition of PARP1 is synthetically lethal due to their dependence on PARP-1 activity for DNA (base excision) repair and subsequently survival.9 So PARP-1 inhibitors have shown success when used as monotherapy for treating genetically DNA repair-defective cancers. Here, BRCA1 is linked to cancer.