CSF-1 levels at death in mice receiving leukemogenic treatment. Mice (N = 220) were treated at 3 months of age with 3 Gy and dexamethasone (0.5 mg subcutaneously); 47% developed RI-AML (▴), 35% developed RCN B (▪), and 18% died tumor-free (•). The number of mice at each time point is shown in parentheses. *Circulating CSF-1 levels in RI-AML mice that were significantly different from the corresponding levels in tumor-free mice (Student's t-test, P < .005).