The fibroblast growth factor receptors are members of the tyrosine kinase superfamily and consist of an extracellular ligand domain composed of three immunoglobulin-like domains, a single transmembrane helix domain, and an intracellular domain with tyrosine kinase activity. (Ornitz, DM. and Itoh, N) Monoclonal antibodies against the high affinity tyrosine kinase Fibroblast Growth Factor (FGF) receptor may help define receptor epitopes involved in FGF binding and signal transduction which mediate coronary and tumor angiogenesis. (Venkateswaran, S., et al).