AKT1 and meningioma: EGFR activates several downstream pathways, primarily those of mitogen-activated protein kinase (MAPK), phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT) and phospholipase C, which have been found to play a role in meningioma pathogenesis (7,9).