All of the other studies we reviewed did reveal a difference in CBC ranging from 1% to 11% in controls to 25% to 42% in mutation carriers when BRCA1/2 mutation carriers were compared to patients with familial, non-BRCA1/2-associated breast cancer and/or sporadic controls [20–23, 25, 41, 42]. This evidence concerns the gene BRCA1 and breast carcinoma.