TP53 and glioblastoma: HIF-1α is also regulated by other oncogenes, including EGFR, and loss of tumor suppression factors, such as p53 and PTEN11 (20–40% incidence of mutation in glioblastoma53); it can also be activated together with VEGF by RTK /PI3K/AKT signaling pathways frequently altered in glioblastoma (in up to 90% of cases)54.