Although there a several potential advantages to using NK cells over T cells, many of the mechanisms that repress T-cell activity in glioblastoma are also active in suppressing NK cell cytotoxicity; TGFβ produced by glioblastoma cells, glioblastoma-associated myeloid cells, or Tregs can repress NK cell cytotoxicity by downregulating the NKG2D activating receptor [82] and it is likely that these immunosuppressive cells also employ additional mechanisms to repress NK cell cytotoxicity. Here, TGFB1 is linked to glioblastoma.