Fibroblast growth factor-9, also called FGF-9, is an approximately 26 kDa secreted glycoprotein of the FGF family. Secreted human FGF-9 is a 205-207 aa protein that lacks the N-terminal 1-3 aa and shares 98% sequence identity with mouse, rat, equine, porcine and bovine FGF-9. In addition to FGF R3 (IIIb), FGF-9 binding to the IIIc splice forms of FGF R1, R2 and R3 are variably reported. FGF-9 is an autocrine/paracrine growth factor considered to be important for the growth and survival of motorneurons and prostate. Meanwhile, FGF9 is a potent mitogen and survival factor required for morphogenesis during embryonic development and numerous biological functions at adulthood. FGF9 have been shown to improve systolic function after myocardial infarction in a clinical trial. FGF9 promotes cardiac vascularization during embryonic development but is only weakly expressed in the adult heart.