TGFB1 and glioma: The cytotoxicity of glioma-associated microglia/macrophages and their ability to induce effective anti-tumor T-cell responses are impaired, most likely due to the glioma-secreted immunosuppressive factors like TGF-β, IL-10, and prostaglandin E2 [117,133,134,135,136,137,138,139].