Talazoparib inhibits PARP1 and PARP2, two key enzymes involved in DDR, and effectively traps PARP on single-stranded DNA breaks, causing an accumulation of double-stranded DNA breaks that cannot be effectively repaired in cancer cells with mutations in DDR/HRR genes, including BRCA1/2 [10–15]. The gene discussed is PARP1; the disease is cancer.