[Angiogenesis--anti-angiogenesis. Significance for tumor growth and metastasis].

Angiogenesis plays an important role in the local growth and metastasis of a variety of malignant tumors. During the past three decades so-called angiogenesis factors have been discovered and characterized in more detail. These are the major contributors to angiogenesis. The term angiogenesis factors includes other functionally heterogeneous molecules. The best characterized angiogenesis factors are endothelial growth factors, such as "vascular endothelial growth factor" (VEGF), "fibroblast growth factor" (FGF), "platelet-derived growth factor" (PDGF), Angiogenin and interleukin-8 (IL-8). However, members of the family of matrix metalloproteinases are also included. The list of factors involved in angiogenessis and their receptors are increasing steadily as does the list of molecules with antiangiogenic capacity. The latter comprises the endogenous factors, Angiostatin, Endostatin, Thrombospondin-1 and 2, and chemical compounds, such as the Fumagillin derivative, AGM-1470, or inhibitors of matrix metalloproteinases. These have attracted more interest during the past years, since investigations on these molecules foster hope for new therapeutic strategies. Some of these antiangiogenic factors have already been used in various therapeutic approaches to influence tumor growth. While impressive results have been obtained in well controlled experimental animal models, the results of clinical studies in humans fall short of these successes. This is at least in part due to the fact that angiogenesis of tumors is a complex process based on the interaction of a variety of factors. The present article summarizes the current knowledge about tumor angiogenesis with a particular emphasis on antiangiogenic molecules. The presented data open new interesting therapeutic perspectives for future dermatology.