There are two critical pathways altered in GBM, the Ras/MAPK (Ras protein/mitogen-activated protein kinase) and PI3K/AKT/PTEN (phosphatidylinositol 3-hydroxy kinase/protein kinase B/PTEN Phosphohydrolase), resulting in oncogenic changes that ultimately lead to uncontrolled invasion and drug resistance. Here, PTEN is linked to glioblastoma.