AMG 330 exerted marked cytotoxic activity in several specimens with very low CD33 expression levels on AML blasts, and we found no significant correlation between CD33 expression levels and drug-induced cytotoxicity (at 250 pg/mL: r = 0.012 [-0.306–0.327], P = 0.94; at 500 pg/mL: r = -0.048 [-0.359–0.272], P = 0.77; Fig 1C). This evidence concerns the gene CD33 and acute myeloid leukemia.