Given that the PARP1-selective inhibitor, saruparib, exhibits a potent effect on SUM149PT survival (half-maximal inhibitory concentration, or IC50 value of 2.8 nM), while the non-selective PARP1/PARP2 inhibitor, veliparib, shows significantly weaker effects (IC50 value of 6.3 μM) (Fig. 1A and Supplementary Fig. S1A), we selected these two PARPi as tool compounds to investigate the properties of PARPi that contribute to their efficacy in BRCA1m cancer cells. This evidence concerns the gene PARP2 and cancer.