Review paper
VEGF and tumor angiogenesis

Angiogenesis is a critical process in tumor growth and development. VEGF is the most specific stimulator of vascular endothelial cell proliferation. VEGF is known to be involved in the growth and development of cancer and is expressed early in the progression of each tumor. High levels of VEGF may also predict poor response to conventional systemic therapy. Two of the novel and most promising targets in treatment of many types of cancer are receptor for epidermal growth factor (EGFR) and VEGF. The last one is the predominant regulator for this pathological process. The most promising drugs are Bevacizumab and Cetuximab. Other growth factors as PDGF, TGF, HGF, and bFGF which are potent endothelial cell mitogens, are relatively nonselective for endothelium and can also stimulate divisions in any other cell types. Thus, in tissues VEGF is most important for activation of angiogenesis process. It is produced in response to different cellular and environmental stimuli.. VEGF has been shown to facilitate survival of existing vessels, contribute to vascular abnormalities that may inhibit effective delivery of antitumor compounds, and stimulate new blood and lymphatic vessels growth. Expression of VEGF also correlates with invasiveness of many types of cancer cells, vascular density in different tumors, appearance of metastasis, tumor recurrence, and poor prognosis for patients including early death.
The objective of this review is to summarize data on various members of VEGF family and on their role in tumor angiogenesis.