Effect of ZOL on the proliferation of JMML and normal BM cells in the suspension culture. (A) Phase microscopy of adherent cells developed from BM cells of a patient with JMML (case 4) and a healthy donor (case 3) at day 15 of suspension culture without and with 10 ng/mL ZOL (microscope, ITM2; camera module, DP50; objective lens, DPlan Ap10 UV, Olympus; numerical aperture, 0.4; magnification, × 40). A number of adherent cells were observed in the culture of JMML cells without ZOL, but their development was suppressed by the addition of ZOL. The growth of adherent cells in the culture of normal BM cells was not affected by the addition of ZOL. (B) The inhibition rate by 1, 10, and 100 μM ZOL in the proliferation of JMML and normal BM cells in the suspension culture without and with 10 ng/mL GM-CSF, respectively, at days 5 and 10. Each value indicates the mean ± SD calculated from the data in 3 patients with JMML and 3 healthy donors. □ indicates ZOL 1 μM; ○, ZOL 10 μM; •, ZOL 100 μM.