Angiogenesis and anti-angiogenesis: Perspectives for the treatment of solid tumors

Angiogenesis is the formation of new blood vessels from preexisting ones. M any solid tumors depend on an extensive neu ly formed vascular network to b ecome nourished and to expand. Tumor cells induce the formation of an exten sive but aberrant vascular network by the secretion of angiogenic factors. A proper context is needed for the endothelial cells to respond. To create this proper context, the tumor often uses the body's own repair system to a ccelerate angiogenesis and the subsequent tumor expansion. The angiogenic r esponse is governed by the interaction of angiogenic growth factors and cyt okines with specific receptors on the endothelium. as well as by the intera ction of these cells with their surrounding matrix. Which is regulated by m atrix-degrading proteases and adhesion molecules such as integrins. A numbe r of agents have been discovered and developed that aim to inhibit angiogen esis and to convert the tumor to a dormant state. They have proven to be ef fective in animal studies. At present their efficacy in man is under evalua tion.