The two breast cancer genes BRCA1 and BRCA2, account for 10-15% of the familial risk of breast cancer, while mutations in other high-risk genes PTEN, STK11, CDH1, and TP53 or in the moderate-risk genes ATM, CHEK2, PALB2, explain around 5% of familial cases [4]. This evidence concerns the gene ATM and breast cancer.