ABCB1 and cancer: Studies have shown that both the multidrug transporter ATP Binding Cassette, sub-family B, member 1 (ABCB1, MDR1) (3,4) and the ATP Binding Cassette, sub-family C, member 1 (ABCC1, MRP1) (5) play a role in enhancing the cellular efflux of anti-cancer drugs, including paclitaxel.