CHEK2 and breast cancer: Next-generation sequencing (NGS) studies have reported that as many as ~18% of patients diagnosed with CRC < age of 50 years have pathogenic germline variants in genes that are not traditionally associated with CRC, including ATM, CHEK2, BRCA1, BRCA2, CDKN2A or PALB27,8, while up to 15% of HBOC patients harbor pathogenic variants in known BC predisposing genes, including RAD51C, RAD51D, ATM, CHEK2, BRIP1, PALB2, BARD1, RECQL, TP53, CDH1 and NBN9,10.