CD8A and central nervous system cancer: TGF-β, the immunosuppressive factor secreted by the brain tumor increases sharply between (0–180) days (Fig 10A), which suppresses the activation and proliferation of macrophages and CD8+ T cells, resulting in the steep growth of the glioma cells in the 2nd, 4th and 6th months (0–180 days) (see Fig 4A).