The ABCB1 3435C>T polymorphism is a synonymous SNP with no impact on the structural contribution of the amino acid at position 1145 (Ile) in the second ATP binding domain but does affect the expression of P-gp in tissues.[22] So far, numerous epidemiological studies have been performed to assess the association between rs1045642 and risk for CRC. The gene discussed is ABCB1; the disease is colorectal carcinoma.