PTGS2 and glioblastoma: During cancerogenesis, the overexpression of COX-2 and high level of its metabolite prostaglandin E2 (PGE2) in GBM cells correlate with a substantial increase of the rate of cell proliferation, adhesion, migration, angiogenesis and metastasis, as well as with immunosuppression of defense mechanisms [20,21,22,23].