AKT1 and glioblastoma: EGF also regulates the serine/threonine phosphorylation pathways such as the phosphatidylinositol- 4,5-bisphosphate 3-kinase/phosphatase and tensin homolog/serine–threonine kinase Akt (PI3K/PTEN/Akt) which is implicated in the pathogenesis of GBM [15,16].