S100A9 and leukemia: Importantly, in responseto tasquinimod treatment, a notable reduction in total leukemic cells (GFP+) inthe peripheral blood (PB) was observed (Fig. 8G).Myeloid cells (Mac-1+) in the GFP+ leukemic cell compartment (Fig. 8H) and the entire PB (Fig. 8I) significantly decreased, indicating that the skewed myeloiddifferentiation of leukemia-initiatingPtpn11E76K/+ stem cells was largelyrectified by blocking S100a9/S100a8 function.