CD38 and acute myeloid leukemia: OST-01 treatment on dose dependent for 24 h significantly inhibits proliferation and colony formation and induces apoptosis in representative AML cell lines (MV-4-11, KG-1a, Kasumi-1 and HL-60), primary CD34 + CD38- blasts (enriched for LSCs; see Table S1 for molecular features), but not normal CD34 + CD38- mononuclear cells (MNCs) [enriched for hematopoietic stem cells (HSC)] (Fig. 1A, B, Fig. S1), suggesting that OST-01 was cytotoxic to AML blasts, but spared normal HSCs.