
The production of VEGF is stimulated by upstream activators, including environmental cues, growth factors, oncogenes, cytokines, and hormones. The binding of VEGF to its receptors on the surface of endothelial cells activates intracellular tyrosine kinases, triggering multiple downstream signals that promote angiogenesis. Although there are multiple variants of both the VEGF ligand and its receptor, the angiogenic effects of this pathway are primarily mediated through the interaction of VEGF-A (the most common variant, often referred to simply as VEGF) with VEGFR-2. Other non-VEGF factors are thought to play a secondary role in angiogenesis, though many of these factors may also impact additional nonangiogenic pathways.3-5,13

More specifically, a number of interrelated signals and processes have been identified that lead to the production of VEGF and, subsequently, to neovascularization of a tumor. The pages that follow provide a detailed explanation of the various steps in the VEGF pathway.
To go directly to a particular section of the pathway, click on the links below.