Second somatic mutations in BRCA1/2 have been reported as the underlying cause of bi-allelic inactivation in tumors from BRCA1/2 germline mutations carriers.27 It should be noted, however, that somatic mutations resulting in the inactivation of the wild-type allele of BRCA1 or BRCA2 in BRCA1− or BRCA2-associated breast cancers, respectively,15,24,28 appear to be less frequent than somatic PALB2 mutations in the context of PALB2-associated breast cancers. The gene discussed is PALB2; the disease is breast cancer.