Several studies and clinical trials [87], have shown that PARP inhibitors influence cancers in which mutations in BRCA1 or BRCA2 are observed, which led us to assume that the cancerous growth-inhibiting interaction of BAP1 with BRCA1 may already be perturbed in this case, and that PARP inhibitors may actually be blocking the novel interaction of BAP1 with PARP3 which enhances cancer growth. This evidence concerns the gene BRCA2 and cancer.