CD34 and acute myeloid leukemia: In an attempt to further determine whether mitochondrial ATPsyn-β is involved in the drug resistance of AML, especially in refractory/relapsed patients, and whether ATPsyn-β is a potential target for the reversal of AML multidrug resistance, we investigated ATPsyn-β expression and mitochondrial ATPase activity in bone marrow mononuclear cells (BMMCs) and CD34+ cells from non-M3 AML patients.