APO866 induces dose-dependent cell death in malignant cells from various hematologic malignancies but not in normal HPCs. Dose-dependent analysis of cell death induced by APO866 on cancer cells from cell lines ML-2 (A), Namalwa (B), and Jurkat (C); primary cells from patients with various hematologic malignancies, AML (D), ALL (E), CLL (F), ML (G); and from normal HPCs (H). Cell death was assessed by flow cytometry using annexin V and 7AAD double staining after 96 hours. The percentage of early apoptotic cells (annexin V⁺7AAD⁻) are shown as white columns and that of late apoptotic cells (annexin V⁺7AAD⁺) are shown as solid black columns. Data are derived from at least 3 independent experiments. AML indicates acute myeloid leukemia; ALL, acute lymphoblastic leukemia; CLL, chronic lymphocytic leukemia; ML, marginal zone lymphoma; and HPCs, hematopoietic progenitor cells.