CD34 and acute myeloid leukemia: In addition to its effect on LSC drug efficacy, phenotypic analysis of KG-1a AML cells treated with PL for 48 h in vitro revealed loss of the AML stem/progenitor markers CD34 and CD123, as well as the myeloid marker CD13, at all concentrations tested (5, 10 and 20 μM) (Fig. 4).