ANGIOGENIC THERAPIES

Primary tumors and metastases require the formation of new blood vessels in order to grow beyond about 1 to 2 m m 3. This process is sustained by different mechanisms: tumors may coopt existing vessels, may induce the formation of new vessels from pre-existing ones or may exploit endothelial precursors originating from the bone marrow. Vessel formation is regulated by a number of pro- and anti-angiogenic molecules, released by tumor cells. There is compelling evidence from experimental work, that inhibiting angiogenesis may induce tumor regression or sometimes cure. Targeting tumor vasculature, composed of genetically stable endothelial cells, has bee