Dose-response curves of daunorubicin. In a single-cell clonogenic assay, RhoD and RhoB leukemic blasts and prestimulated RhoD cells with HGFs for 48 hours were exposed to increasing concentrations of anthracycline. Proliferation was expressed as the percentage clusters (>10 cells/well) in medium A with daunorubicin compared with the control (medium A without daunorubicin). The IC50 of daunorubicin of RhoD and RhoB cells of patient no. 1 (A) were 0.008 μg/mL and 0.004 μg/mL and of patient no. 5 (B) 0.006 μg/mL and 0.003 μg/mL, respectively. The IC50 of daunorubicin of RhoD cells of patient no. 5 decreased from 0.006 μg/mL to 0.003 μg/mL after prestimulation with HGFs (B).