IL6 and glioblastoma: Approximately 1000 proteins were identified with a mass spectrometry analysis in GBM exosomes, which are pro-angiogenic factors (interleukin-6 (IL-6), IL-8, angiogenin, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2) in endothelial cells of normal brain and enhance malignancy by causing hypoxia [66,67].