Figure 1.

Schematic representation of Receptor Tyrosine Kinases (RTK) activation and the downstream signaling. RTKs, particularly epidermal growth factor receptors (EGFR), are amplified in glioblastoma, which significantly alters the nutrient uptake and utilization. The Rapidly Accelerating Sarcoma/mitogen activated protein kinase/extracellular-signal-regulated kinase (Ras/MAPK/ERK) and phosphatidylinositol 3-kinase/a serine/threonine protein kinase/mammalian target of rapamycin (PI3K/AKT/mTOR) pathways get activated through the stimulation by growth factor receptor (GFR). Physiologically, these two pathways orchestrate to execute cell proliferation, survival, motility, adhesion, and angiogenesis. Any deregulation in these pathways leads to an activation of oncogenic signaling cascades causing glioma.