Gene Variants Associated With Breast Cancer In Individuals At High Breast Cancer Risk.

It is estimated that 3% to 5% of women presenting for assessment for hereditary breast/ovarian cancer risk have a variant in a gene that moderately increases the risk of cancer. CHEK2, ATM, and BARD1 variants are considered to be of moderate penetrance. Female carriers of CHEK2, ATM, and BARD1 have an approximately 2- to 4-fold increased risk of developing breast cancer compared with the general population. Risk estimates may be higher in patients with a family history of breast cancer or a family history of a specific variant. Germline genetic testing for BRCA1, BRCA2, and PALB2 is addressed separately in evidence review 2.04.02.