Figure 1.

Intracellular signal transduction pathway.

EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; GRB2, growth factor receptor-bound protein 2; HGF, hepatocyte growth factor; IGF, insulin-like growth factor; IGFR, insulin-like growth factor receptor; MAPK, mitogen-activated protein kinase; MET, mesenchymal epithelial transition factor; mTOR, mammalian target of rapamycin; PI3K, phosphatidylinositol 3 kinase; PIP2, phosphatidylinositol-biphosphate; PIP3, phosphatidylinositol triphosphate; PTEN, phosphatase and tensin homologue; RAS, rat sarcoma; SOS, son of sevenless protein; STAT, signal transducers and activators of transcription protein; VEGF, vascular endothelial growth factor; VEGFR, vascular endothelial growth factor receptor.