PTEN and glioblastoma: At present, many molecular biomarkers for prognosis have been identified from GBM tissues, such as O-6-methylgua-nine-DNA methyltransferase (MGMT), isocitrate dehydrogenase 1 and 2 (IDH1/2), p53, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), and 1p/19q [3].