Notably, poly(ADP-ribose) polymerase (PARP) inhibitors have emerged as a prominent example. PARP inhibitors are employed in the treatment of cancer cells with mutations in BRCA1 or BRCA2, which are deficient in homologous recombinational (HR) repair for repairing DNA double-strand breaks (DSBs). The gene discussed is BRCA1; the disease is cancer.