MLH1, XRCC4, 53BP1, ERCC1 and XPA in breast cancer related studies, XRCC4 may be associated with breast cancer risk and the age at which breast cancer is diagnosed23, 53BP1 might be a crucial regulator of breast cancer migration and invasion24, women who can detect ERCC1 and XPA are at higher risk of breast cancer25, MLH1 and MSH2 loss may lead to advanced breast cancer26. This evidence concerns the gene XRCC4 and breast cancer.