Known susceptibility genes account for less than25% of the familial risk of breast cancer, and the residual genetic variance is likely to be due to variants conferring more moderate risks.

• 大家知道乳腺癌的家族危险性的小于25%25由于易感基因，而剩余的遗传变异更多是由于变异体，而这种变异引起更多的风险。