Vascular endothelial growth factor (VEGF) is a signalling protein that promotes the growth of new blood vessels. VEGF forms part of the mechanism that restores the blood supply to cells and tissues when they are deprived of oxygenated blood due to compromised blood circulation.
One of the main functions of VEGF is to form new blood vessels as a baby grows and develops in the womb. This protein also stimulates the growth of new blood vessels after injury and the growth of muscle after exercise has been performed. In cases where blood vessels are obstructed, VEGF also promotes the creation of new blood vessels to bypass the blocked vessels.
Problems with VEGF
The overexpression of VEGF is a contributing factor to the development of disease. For example, solid tumors require an increased blood supply if they are to continue growing beyond a certain size and tumors that express VEGF are able to continue growing because they can develop this enhanced blood supply, a process referred to as angiogenesis. Cancers that express VEGF are therefore able to grow and spread (metastasize) to other organs and regions of the body.
The overexpression of VEGF can also lead to vascular disease in the retina and other body parts. Expression of this protein has also been associated with a poor outcome in breast cancer. A decreased level of VEGF in the pulmonary arteries has been associated with the condition pulmonary emphysema.
VEGF in therapeutics
Since cancer growth is stimulated by VEGF, researchers have made numerous attempts to decrease its expression to prevent angiogenesis and tumor growth. If the blood supply is reduced, the tumor is literally “starved” to death. Two drugs that have been successful at slowing the progression of diseases that rely on VEGF are bevacizumab and ranibizumab.