CHEK2 and breast cancer: In All CHEK2 heterozygotes, there was a significant excess risk (Bonferroni-adjusted SAIGE p-value) of all cancers, breast cancer (C50), male genital organ cancer (C60-C63), urinary tract cancer (C64-C68), thyroid and other endocrine gland cancer (C73-C75), and lymphoid, hematopoietic, and related tissue cancer (C81-C96).