CHEK2 and breast cancer: P/LP germline variants in ATM, BRCA1, BRCA2, CDH1, CHEK2, PALB2, PTEN, STK11, and TP53 genes have been linked to an elevated risk of breast cancer, whereas APC, CHEK2, MLH1, MSH2, MSH6, PTEN, and STK11 have been identified as causal genes in colorectal cancer.29, 30