ANGIOGENESIS FACTORS AND TUMOR-GROWTH

The formation of new blood vessels (angiogenesis) is a crucial step in the development of most solid tumors. Major advances in the identification of molecular actors that are presumably involved in the angiogenic process have been obtained by studies on cultured endothelial cells. However one may wonder if these actors that are active in vitro and in various angiogenic assays are actually expressed in vivo during angiogenesis. Using specific nucleotidic probes and antibodies it became recently possible to detect in vivo these presumptive molecular actors including angiogenic factors, matrix degrading proteases and their inhibitors, and transcription factors. The results of this contextual analysis, although fragmentary, challenge the models derived from in vitro analysis. These results will be essential for designing specific strategies aiming at the inhibition of tumor angiogenesis, which may result in limiting the proliferation and spreading of tumor cells.