Recent studies have shown that the disruption of any HR-related pathway, such as by BRCA mutations, and disruption of Fanconi anemia, and ATM genes, can predict the sensitivity of tumors to the inhibition of PARP1 by small-molecule inhibitors and the associated cytotoxicity (D'Andrea, 2010; Mateo et al., 2015; O'Connor, 2015; Pommier et al., 2016). The gene discussed is ATM; the disease is Fanconi anemia.