A study on over 3900 women with breast cancer who met or did not meet the NCCN 2020 v.1 criteria confirmed the mutation rate of 9.0% vs. 3.5% on the 9 predisposition genes (ATM, BRCA1, BRCA2, CDH1, CHEK2, NF1, PALB2, PTEN and TP53) [24]. This evidence concerns the gene CHEK2 and breast cancer.