[Tumor angiogenesis].

Following the work of Folkman, it appears that angiogenesis, which consists in the formation of new blood vessels able to deliver oxygen and nutriments to tumor cells, is a major step in the evolution of tumors, which can only grow after the onset of the angiogenic switch. Numerous factors play a role in angiogenesis stimulation or inhibition : the vascular endothelial growth factor and fibroblastic growth factors as well as angiopoietin are proangiogenic, whereas angiostatin and platelet factor 4 are anti-angiogenic. The discovery of these molecules and of the molecular mechanisms of their activity allowed the identification of new therapeutic targets, which appear relevant for the treatment of cancer.