Genotypes 51Gln/His and 148Asp/Glu of APEX gene and 23Gly/Ala of XPA gene may increase the risk of CRC, while polymorphisms of 64Ile/Val of APEX gene and 689Ser/Arg of ERCC4 gene have no effect on modulating the risk. The gene discussed is ERCC4; the disease is colorectal carcinoma.