VEGFA and medullary thyroid gland carcinoma: VEGF inhibitors may be used as monotherapy or in combination with other chemotherapeutic agents, and they have been approved for treatment of many tumor types, including colorectal, NSCLC, breast, glioblastoma, renal cell carcinoma, hepatocellular carcinoma, gastrointestinal stromal tumor, pancreatic neuroendocrine tumors, and medullary thyroid cancers.176 Disruption of VEGF signaling, either by blocking VEGF directly or the tyrosine kinase receptor at which it exerts its effects, has been shown to slow tumor progression by preventing new vessel formation.