Growth factors and angiogenesis.

The list of growth factors with angiogenic potential is growing. It is not clear why so many factors with angiogenic potential exist, although Folkman postulated that this apparent redundancy is indicative of the essential nature of the angiogenic response. Additionally, these factors or their close relatives have other biological activities, including developmental morphogenesis, tumourigenesis, regeneration of injured tissue, and immunosignalling. Recent advances in the understanding of these factors include primary peptide sequence for all but one peptide growth factor included in this review, identification of cell surface receptors for many, and extensive characterisation of biological potential. Despite the torrent of data on angiogenic growth factors in the last decade, the chasm between form and physiology remains formidable.