Folate receptor 1 (FOLR1), also known as folate receptor alpha, folate-binding protein (FBP), FOLR, is a member of the folate receptor (FOLR) family. Members of this gene family have high affinity for folate and various reduced folate derivatives, mediating the transfer of 5-methyltetrahydrofolate into cells. Mature FOLR1 is a glycosylated protein anchored to the cell surface by GPI linkage. FOLR1 is primarily expressed on epithelial cells and significantly upregulated in many tumors.