TGFB1 and central nervous system cancer: Alternatively, M2 (Arg1+, CD36+, CD206+, Ym1+) phenotypes, mostly found in the ischemic core region, secrete IL4, IL10, and IL13 and TGFβ, IGF1, NGF, and BDNF for neuroprotection, inhibition of apoptosis and necrosis, tissue and ECM repair and cleanup of debris via phagocytosis.177–180 Transformation of these microglia from M1 (tumor suppressive) to M2 (tumor promoting) form initiates immune suppression in the tumor area and also promotes tumor expansion, metastasis, angiogenesis, and glioma stem cell maintenance via the secretion of several factors (viz.