ABCB1 and cancer: P-glycoprotein (Pgp, ABCB1) is a member of the ATP-Binding Cassette (ABC) transporter superfamily and plays an important role in the development of multidrug resistance (MDR) in cancer cells.  This transporter utilizes energy from ATP hydrolysis for the efflux of a variety of chemically dissimilar amphipathic compounds, including anticancer drugs [1].