Development and validation of a residual risk score to predict breast cancer risk in unaffected women negative for mutations on a multi-gene hereditary cancer panel.

1579 Background: Women who are unaffected with cancer but have a significant family history of breast cancer (BC) are frequently referred for hereditary cancer testing with multi-gene panels; however, < 10% test positive for clinically actionable mutations. Large-scale genotyping studies have identified common variants (primarily single-nucleotide polymorphisms) that individually confer modest BC risk, but together may explain the genetic...