Influence of family history on penetrance of hereditary cancers in a population setting.

Background: We sought to investigate how penetrance of familial cancer syndromes varies with family history using a population-based cohort.

Methods: We analysed 454,712 UK Biobank participants with exome sequence and clinical data (data collected between March 2006 and June 2021). We identified participants with a self-reported family history of breast or colorectal cancer and a pathogenic/likely pathogenic variant in the major genes responsible for hereditary breast cancer or Lynch syndrome.