Vascular endothelial growth factor (VEGF) Tumors cannot grow without new vessel formation (angiogenesis).
The dominant growth factor controlling angiogenesis is vascular endothelial growth factors (VEGFs). 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 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.