Methods to evaluate the formation and stabilization of blood vessels and their role in tumor growth and metastasis.

It is becoming more and more clear that angiogenic mechanisms leading to structural formation of blood vessels are very complex, and understanding them depends on studies performed by means of a wide methodological spectrum ranging from molecular biological techniques to morphological analyses (1-4). To study the maturation and stabilization of newly formed blood vessels, processes that include many successive steps, the following aspects and methods are important: 1. Examination of structural components of the vascular wall indicating vascular stabilization by means of light and electron microscopy. 2. Immunohistochemical and immune electron microscopic studies on tissues and cells with improved methods for precise localization of angiogenic factors during vascular maturation. 3. Chemotactic assay on human endothelial cells using the Boyden chamber to test their migration response to angiogenesis activators and inhibitors. 4. Three-dimensional endothelial tube formation assay on collagen gel: an in vitro angiogenesis model. 5. Chorioallantoic membrane (CAM) assay as an easy in vivo angiogenesis assay.