ABCC4 and malignant colon neoplasm: To identify the ABC transporter genes regulated by c-MYC in human colon cancer cells, we investigated the effect of c-MYC knockdown on MDR1, MRP1, ABCB5, ABCC4 and ABCC5 expression levels, which are closely involved in the resistance to chemotherapeutic agents including 5-FU 17–23.