Vascular endothelial growth factor (VEGF) is a signal protein produced by cells that stimulates vasculogenesis and angiogenesis. It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate, such as in hypoxic conditions.
The dominant growth factor controlling angiogenesis are VEGFs.
When VEGF is overexpressed, it can contribute to disease. Solid cancers cannot grow beyond a limited size without new vessel formation (angiogenesis), and cancers that can express VEGF are able to grow and metastasize.

The VEGFs bind to VEGF receptors (VEGFRs), tyrosine kinase receptors on the cell surface. This can be reduced by using the VEGF-blocking monoclonal antibody bevacizumab, by providing decoy receptors to reduce binding on true receptors (aflibercept), or by employing the small molecule tyrosine kinase inhibitors (TKIs), such as sorafenib and sunitinib that inhibit the enzyme in the receptor.


Epidermal growth factor (EGF)
The epidermal growth factor (EGF) proteins promote cell proliferation and differentiation by binding to the EGF receptor (EGFR), a tyrosine kinase receptor present on the cell surface. This can be blocked by the EGFR inhibitor monoclonal antibody cetuximab, or small molecules that block the tyrosine kinase enzymes (TKIs), such as gefitinib and erlotinib.

Adapted from Wikipedia, the free encyclopedia. Internet. Accessed on October 25, 2016.