ABCB1 and acute myeloid leukemia: Anthracyclines, quinone-based chemotherapeutics that are the backbone of chemotherapy regimens commonly used to treat AML, are substrates of the ATP-binding cassette protein drug efflux pumps ABCB1 (P-glycoprotein) and ABCG2 (breast cancer resistance protein), which are expressed on AML cells and other cancer cells [24].