Among them, the ABC transporter subfamily B member1 (ABCB1/MDR1/P-glycoprotein, P-gp), subfamily C member 1 (ABCC1/MRP1) and subfamily G member 2(ABCG2/BCRP) are considered to be the most important transporters to confer MDR to tumor cells. This evidence concerns the gene ABCB1 and neoplasm.