TUMOR ANGIOGENESIS - A PHYSIOLOGICAL PROCESS OR GENETICALLY-DETERMINED

Continued tumor growth is dependent upon the growth of new blood vesse ls. This commentary reviews the mechanisms whereby tumors become vascu larized and examines whether tumor angiogenesis is solely an example o f a normal physiologic process or is part of the genetic program of th e tumor. The likelihood that neovascularization of tumors combines bot h of these components, that is, utilizing tumor-specific elements as w ell as capacities common to all cells, is discussed.