HIF1A and glioma: Compared to normal brain, glioma is characterized by increased aerobic glycolysis, leading to hypoxic local tissue, the production of HIF-1α and TGF-β, the activation of immunosuppressive CD4+ T cells and inhibition of NK cell activity, creating an acidic, hypoxic and immunosuppressive TME that is conducive to malignant invasion, metastasis and immune resistance (161–163).