TGFB1 and glioblastoma: Many of the TME features are linked to GBM invasiveness; in fact, proteases and transcription factors required for the initiation of epithelial mesenchymal transition (EMT), are triggered by TGF-β, EGF, PDGF, and FGF2, produced by circulating or residential myeloid cells, which are recruited in hypoxic and inflammatory conditions [90].