FLT3^wt/ITD, FLT3^−/ITD, and FLT3^ITD/ITD mice develop progressive, fatal MPN. (A) Kaplan-Meier plots (n = 20 for each group). (B) Spleen weights. (C) Peripheral WBC counts (i), hemoglobin (ii), platelet counts (iii), and WBC differential (iv) in 2-month-old FLT3^wt/wt, FLT3^wt/ITD, FLT3^−/ITD, and in 3-week-old FLT3^ITD/ITD mice