In the present study, we have investigated the relationship between single nucleotide polymorphisms (SNP) in CYP1A2, CYP1B1, CYP3A4, CYP3A5, CYP11A1, CYP17A1 and CYP19A1 and CRC risk in a large study of 2,575 cases and 2,707 controls. The gene discussed is CYP3A4; the disease is colorectal carcinoma.