Figure 1.

Molecular pathways implicated in neuroendocrine tumors and targets of action for therapeutic agents. Arrows represent activation whereas lines with a perpendicular block represent inhibition.

Abbreviations: EGFR, endothelial growth factor receptor; IGF-1R, insulin-like growth factor 1 receptor; mTOR, mammalian target of rapamycin; PDGFR, platelet-derived growth factor receptor; SSTR, somatostatin receptor; VEGF, vascular endothelial growth factor; VEGFR, vascular endothelial growth factor receptor.