ERBB2 and neoplasm: Two scenarii might be possible to explain the case: (1) it is sporadic HER2-positive breast cancer developed in a patient with BRCA1 germline mutation and not causally linked to the tumor suppressor gene BRCA1 loss-of-function and in such case we could introduce the notion of incidental genomic event, or (2) it is a rare subgroup of breast cancers occurring in patients carrying BRCA1 germline mutation in which BRCA1 loss of function and HER2 overexpression cooperate in the oncogenesis of the tumor.