Approximately 50% of AML patients have blast cells that express ABCB1 [5] and over-expression of ABCB1 was associated with lower complete remission (CR) rates and higher relapse rates in patients treated with standard chemotherapy based on the combination of an anthracycline with cytarabine [5,6,7,8]. The gene discussed is ABCB1; the disease is acute myeloid leukemia.