Effect of ZOL on the colony formation from JMML and normal BM cells at less than 10 μM. BM cells of a patient with JMML (case 7) and a healthy adult (case 6) were incubated in the clonal culture with concentrations of 0, 1, 3, 6, and 10 μM ZOL for 14 days in the absence and presence of GM-CSF (10 ng/mL), respectively. ▪ indicates GM colonies; ▦, G colonies.