ITGAX and leukemia: Within the myeloid cell lineage, MerTK is commonly expressed on mature macrophages, including leukemia-associated macrophages (LAMs; CD11b+CD11c+Gr-1-), but not on monocytes (CD11b+CD11c-Gr-1-SideScatterlo), granulocytes (CD11b+CD11c-Gr-1+SideScatterhi), or myeloid-derived suppressor cells/myeloid progenitors (MDSCs; CD11b+CD11c-Gr-1intermediateSideScatterhi) (19).