It is now well established both experimentally and clinically, that new blood vessel growth is required for tumors to grow beyond a few millimeters and metastasize [Folkman, J. (1995). In: Mendelsohn, L., Howley, P., Israel, A. (Eds.), The Molecular Basis of Cancer, WB Saunders Company, Philadelphia, pp. 206–225]. Angiogenesis, the process of forming new blood vessels from preexisting vessels, provides the tumor with additional oxygen and nutrients for its continued growth. In addition, the proximity and increase in vascular density enhance the likelihood of tumor cells entering the bloodstream to eventually metastasize. Since the initial observations of Dr. Folkman in the late 1970s, research over the past 30 years has focused intensely on identifying points in which the angiogenic cycle can be disrupted and has become an important component of current therapies to limit tumor progression.