In addition, the glioma TME plays an important role in suppressing NK cell function, since TGFβ, which is secreted by cancer and noncancer cells, downregulates the expression of NKG2D-activating receptor on NK cells isolated from GBM patients.44 Thus, the role of NK cells in anti-glioma surveillance remains to be demonstrated. This evidence concerns the gene TGFB1 and glioma.