Angiogenesis and Cancer

Angiogenesis, the creation of neovasculatures from pre-existing ones, is required for various physiological processes. However, pathological angiogenesis is a hallmark of malignant tumors, metastasis and various ischemic as well as inflammatory disorders. Angiogenesis is regulated by the balance between proangiogenic factors and antiangiogenic factors, and concentrated effort in this area of research has led to the discovery of a growing number of angiogenesis-associated factors and the complex interactions among these factors. Understanding of the regulatory mechanisms of these factors in mediating the angiogenic process involved in tumor growth prompted the application of antiangiogenic factors on experimental tumor models with successful outcomes. Based on these experimental results, some antiangiogenic agents have been tested in clinical trials. In this review, the process and regulators of angiogenesis, the involvement of angiogenesis in cancer development and the application of antiangiogenic therapies on established tumors would be discussed. Among various antiangiogenic reagents, special emphasis will be given to antiangiogenic reagents derived from vascular basement membranes, a crucial regulator of angiogenesis, rather than a structural tissue component.