FLT3 and acute myeloid leukemia: Moreover, although the bulk neutrophil progenitor population was significantly increased in the Flt3 ITD mice (p = 2.5 × 10−3; Figure 2E), our single-cell-level evaluation revealed a significant depletion of later neutrophil progenitors (Figure 2F), suggesting a differentiation block at the late neutrophilic progenitor stage, which is consistent with the observation of terminal neutrophilic differentiation of FLT3 ITD-positive AML blasts after treatment with FLT3 inhibitors.23