In the CNS, cultured cells of the highly malignant brain tumor glioblastoma multiforme grown under hypoxic conditions secrete exosomes enriched in hypoxia-regulated mRNAs and proteins like caveolin 1, which is also increased in exosomes isolated from the plasma of glioblastoma patients with a poor prognosis [196]. This evidence concerns the gene CAV1 and glioblastoma.