The vertebrate fibroblast growth factor receptor (FGFR) family is an important group of proteins involved in embryonic development and the growth and proliferation of adult cells. Mutations in FGFR proteins can lead to pathologies including bone or limb defects and various forms of cancer. FGFR proteins are receptor tyrosine kinases that, upon ligand binding, dimerize and signal through the MAPK and PLCĪ³ pathways.