PDGFB and glioma: In GEMMs of platelet derived growth factor subunit B (PDGFB)-driven glioma, it has been shown that TAMs derived from bone marrow-derived monocytes constitute the major proportion (up to 85%) of TAMs in the GBM TME, whereas those derived from brain-resident microglia constitute only 15% of the total TAM population in GBM [141].