FLT3 and central nervous system cancer: For example, using Flt3–Cre lineage tracing, microglia-derived TAMs composed about 65% of the bulk TAM population in glioma, while using CX3CR1GFP/WT; CCR2RFP/WT knock-in mice, over 85% of the TAMs within the glioma are thought to be derived from inflammatory monocytes [31,32].