Morphology of t(11;17) positive leukemia cells cultured with G-CSF and ATRA. Mononuclear cells, consisting of more than 90% of leukemic cells, were isolated from the blood at first diagnosis and cultured under various conditions for up to 14 days. Cytospins were made after various time intervals and stained with May-Grünwald-Giemsa. Depicted are uncultured cells (A) and cells that were grown for 1 week in medium (B), 10⁻⁶ mol/L ATRA (C), 0.1 μg/mL G-CSF (D), and ATRA and G-CSF (E).