Physiology and therapeutics of vascular endothelial growth factor in tumor immunosuppression.

Vascular endothelial growth factor (VEGF), known as a primary mediator of tumor-induced angiogenesis, is now understood to have a role in tumor-associated immunosuppression. Initially, VEGF was identified to alter the growth and maturation of the immature granulocyte-macrophage progenitors, and more recently it has been noted that it prevents dendritic cell (DC) precursors from developing into mature, antigen-presenting DC. VEGF is associated with recruitment of macrophages to the tumor stroma and VEGF inhibition of myeloid progenitor maturation is associated with the development tumor associated macrophages (TAM) which possess immunosuppressive capacity as well. Therapies intended to inhibit VEGF or VEGF receptors have demonstrated improved anti-tumor immunity and enhanced responses to cancer vaccines.