Allergy-immunology glossary

Mast cells VEGF is a highly specific mitogen for vascular endothelial cells. Five VEGF isoforms are generated as a result of alternative splicing from a single VEGF gene. The expression of VEGF is potentiated in response to hypoxia, by activated oncogenes, and by a variety of cytokines. VEGF induces endothelial cell proliferation, promotes cell migration, and inhibits apoptosis. In vivo VEGF induces angiogenesis as well as permeabilization of blood vessels, and plays a central role in the regulation of vasculogenesis. Deregulated VEGF expression contributes to the development of solid tumors and to several additional diseases by promoting tumor angiogenesis. Consequently, inhibition of VEGF signaling abrogates the development of a wide variety of tumors. The various VEGF forms bind to two tyrosine-kinase receptors, VEGFR-1 (flt-1) and VEGFR-2 (KDR/flk-1), which are expressed almost exclusively in endothelial cells. 1 يناطبلا ومنلا لماع يئاعولا ٢