TNF and glioblastoma: In addition, hypoxia-regulated expression of GLUT1 identified at different stages of glioblastoma oncogenesis, as tumor cells and macrophages under hypoxic conditions migrated to the foci of necrosis secrete factors that stimulate angiogenesis, including VEGF, platelet-derive growth factor, transforming growth factor β, epidermal growth factor, tumor necrosis factor-alpha, and activation of matrix metalloproteinases [28].