MDC1 and Hereditary breast and ovarian cancer syndrome: Ataxia telangiectasia mutated (ATM) and Nijmegen breakage syndrome (NBS1) cooperatively sense DNA damage and post-translationally modify transducers such as BRCA1 (early-onset familial breast and ovarian cancer), MDC1 (mediator of DNA damage checkpoint 1), 53BP1 (p53-binding protein 1), and c-Abl [62, 63].