XRCC1 and breast cancer: Among DNA repair genes, XRCC1 Arg399Gln has been reported in breast cancer and skin cancer [16, 40], while XPD C156A was correlated with basal cell carcinoma [41], and the hOGG1 Ser326Cys polymorphism has been studied as a causal factor in lung and esophageal cancers [20, 42, 43].