TGFB1 and glioma: In adult-type gliomas, lymphocyte infiltration and PD-L1 are more abundant in tumors of higher grade,10 but anti-PD-L1 immunotherapy has not met the initial clinical expectations.11 The reason for the failure of this therapy could be related to glioma cells producing immunosuppressive cytokines such as transforming growth factor β (TGF-β), which inhibit immune cells.12