As homologous recombination repair (HRR) pathway is impaired in BRCA1-mutated tumor cells, PARP inhibition in these cells can lead to the accumulation of DNA damage and ultimately induce cell death because of impaired DNA damage repair (DDR) from both base-excision repair (BER) and HRR dysfunctions (120). The gene discussed is BRCA1; the disease is neoplasm.