Putting the neo into neoangiogenesis

Angiogenesis is the process by which new blood vessels develop by sprouting of preexisting vessels, and until recently this was considered the sole mechanism of blood vessel formation in postnatal life.The development of the vascular system in the embryo, termed vasculogenesis, is due to in situ differentiation of endothelial progenitors or angioblasts.Studies over the last five years have modified this dogma, since endothelial stem cells have been identified in the adult and have been shown to participate in new blood vessel formation in normal and pathological states, including tumor "neoangiogenesis" (1-5).