BRCA1 and breast cancer: Individuals carrying pathogenic or likely-pathogenic (P/LP) variants in BC genes with ORs > 5 (BRCA1, BRCA2, TP53, PALB2, and PTEN) were excluded prior to PRS calculation (n = 629) (Methods), resulting in a final sample of 5598 women with a history of BC, and 8767 unphenotyped controls (Table 1).