BRCA1 and neoplasm: Cells with HR deficiency (HRD), e.g., cells with mutations in the tumor suppressors BRCA1 or BRCA2, have diminished HR-mediated repair [9] and are more dependent on alternative, lower fidelity repair pathways such as non-homologous end-joining (NHEJ) and alternative end-joining (alt-EJ) to prevent the lethal effects of DSBs [10,11].