Currently, more BC predisposition genes have been identified, including genes with high penetration (TP53, CDH1, PTEN, and STK11), moderate penetration (PALB2, CHEK2, ATM, NBN, etc.), and low penetration (MLH1, MSH2, MSH6, PMS2, MEN1, etc.)12–14. Here, MLH1 is linked to breast cancer.