Tumor angiogenesis--a new therapeutic target in gliomas.

Tumor growth is critically dependent on angiogenesis, which is sprouting of new vessels from pre-existing vasculature. This process is regulated by inducers and inhibitors released from tumor cells, endothelial cells, and macrophages. Brain tumors, especially glioblastoma multiforme, have significant angiogenic activity primarily by the expression of the angiogenic factor VEGF Anti-angiogenic therapy represents a new promising therapeutic modality in solid tumors. Several agents are currently under evaluation in clinical trials. The present review describes the principal inducers and inhibitors of angiogenesis in tumors and summarizes what is known about their mechanisms of action in relation to CNS tumors. Potential areas for clinical use are also discussed.