Therefore, genetic polymorphisms of CYP1A1-rs1048943, GSTM1, GSTT1, mEH-rs1051740 and XRCC1(rs1799782, rs25489), methylation of p16 and RASSF1A gene, and telomere length were analyzed in peripheral blood both from lung cancer patients and health controls to explore their correlation. Here, XRCC1 is linked to lung cancer.