FGFR1: The FGFR1 gene provides instructions for making a protein called fibroblast growth factor receptor 1. This protein is one of four fibroblast growth factor receptors, which are related proteins that are involved in important processes such as cell division, regulation of cell growth and maturation, formation of blood vessels, wound healing, and embryonic development. The FGFR1 protein spans the cell membrane, so that one end of the protein remains inside the cell and the other end projects from the outer surface of the cell. This positioning allows the FGFR1 protein to interact with other proteins called fibroblast growth factors outside the cell and to receive signals that help the cell respond to its environment. When a fibroblast growth factor attaches to the FGFR1 protein, the receptor triggers a cascade of chemical reactions inside the cell that instruct the cell to undergo certain changes, such as maturing to take on specialized functions. The FGFR1 protein is thought to play an important role in the development of the nervous system. This protein may also help regulate the growth of long bones, such as the large bones in the arms and legs. Alterations in the activity (expression) of the FGFR1 gene are associated with certain cancers. The altered gene expression may enhance several cancer-related events such as cell division, cell movement, and the development of new blood vessels that nourish a growing tumor. The FGFR1 gene is abnormally active (overexpressed) in certain types of stomach and prostate cancers. This amplification is associated with tumor progression and a poorer outcome. Altered FGFR1 gene expression has also been found in pancreatic, esophageal, ovarian, testicular, breast, and head and neck cancers.