FGFR1 is a tyrosine kinase receptor and is a member (1 of 4) of the fibroblast growth factor receptor (FGFR) family. FGFR1 differs from other members in the family in part by affinity to fibroblast growth factors(FGF) of which there are 22 members), having highest affinity for FGF1 (acidic) and FGF2 (basic). Upon activation, FGFR1 signals activation of downstream pathways, including RAS/RAF/MAPK, PI3K/ATK/mTor and Jak/STAT pathways, among others.