FGFR1 (Fibroblast growth factor receptor 1), also known as fms-related tyrosine kinase-2/Pfeiffer syndrome, is a member of the fibroblast growth factor receptor (FGFR) family. FGFR family is cell surface membrane receptor that possesses tyrosine kinase activity. When combined with appropriate FGF, FGFR1 elicits cellular responses such as proliferation, migration, and differentiation by activating a series of intracellular signaling pathways including Ras subfamily/ERK, PKC, phospholipase C/PI3K/AKT, Ip3-induced raising of cytosolic Ca2+, Ca2+/calmodulin-activated elements and pathways.