Angiogenesis Factor(s)

TLDR: The hypothesis that angiogenesis is due to the production of a factor(s) by cells involved in the process of neovascularization arose from several kinds of observations.

Abstract: New formation of vessels occurs during embryonal development and throughout the lifespan of an organism following repair processes or under certain pathologic conditions. In particular, neoplastic cell populations can grow to form a clinically evident tumor only if the host produces a vascular network sufficient to sustain tumor growth (Folkman, 1974 a, 1975; Brem et al., 1976). The hypothesis that angiogenesis is due to the production of a factor(s) by cells involved in the process of neovascularization arose from several kinds of observations: During an inflammatory response, new formation of vessels appeared when certain types of cells invaded the area; a neoplastic cell population induced the formation of a vascular network even when the tumor fragment was separated from the host by a Millipore filter; (Greenblatt and Shubik, 1968); and cell-free fluid sampled in vivo from the extracellular compartment of a growing tumor elicited an angiogenic response (Gullino, unpublished observation), as does the media of cultured neoplastic cells (Folkman, 1974 b).