IL2 and cancer: IL-2 and IFN-γ enhance the surveillance of cancer cells by the immune system by promoting the growth and activation of T cells and NK cells.86–89 In contrast, the downregulation of NK cell function in gliomas may be partly due to the increased levels of TGF-β and IL-10 in the plasma90,91 (Fig. 3), activating ligand downregulation and inhibitory ligand overexpression.92 Similar to other immunocytes, NK cells are also inhibited in GBM by upregulation of immune checkpoint molecules and the accumulation of immunosuppressive cells.93