Talazoparib (Figure 4) is a PARPi (poly(ADP-ribose) polymerase inhibitor) that exhibits its anti-tumor activity by firmly trapping PARP onto damaged DNA, thereby causing cell death in BRCA-mutated BC; it has been reported in a two-part, phase I, first-in-human trial to exert a 50% objective response rate (ORR), a PFS of 34.6 weeks, and one complete response in 14 BRCA-mutated BC patients treated with 1.0 mg/day talazoparib [74]. Here, PARP1 is linked to breast cancer.