Consistent with a previous report that CD11b-positive macrophages/microglia constitute approximately 20% of total glioma cells [24], we found that recruited macrophages (GFP+/CD11b+: 57.97% ± 2.96%) were almost two times as common as resident microglia (GFP−/CD11b+: 39.27% ± 1.84%) (Figure 4Db). This evidence concerns the gene ITGAM and central nervous system cancer.