Treatment of c-Cbl RING finger mutant mice with AC220 results in a significant reduction in Flt3⁺ MPPs. (A) BM cells were analyzed by flow cytometry and shown are examples of the gating parameters used to identify Lin⁻ cells, LSK cells, and LSK Flt3⁺ cells from c-Cbl^A/− mice treated with vehicle or AC220 for 6 weeks. (B) Cumulative data showing Flt3 profiles of LSK cells from four 8- to 9-month-old c-Cbl^A/− mice that were dosed for 6 weeks with vehicle or AC220. Three mice were also analyzed 4 weeks after AC220 dosing was discontinued. The gate showing the percentage of Flt3⁺ LSK cells is indicated in each profile. The percentages of Flt3⁺ LSK cells for each treatment group are expressed as means ± SEM.