FGF Receptor 2IIIb (FPR2-D) Mouse mAb #52742

Fibroblast growth factors (FGFs) produce mitogenic and angiogenic effects in target cells by signaling through cell surface receptor tyrosine kinases. There are four members of the FGF receptor family (FGFR1-4) that share between 56 and 71% sequence identity (1). Following ligand binding and dimerization, the receptors are phosphorylated at specific tyrosine residues, initiating downstream signaling pathways (2). Mutations in the FGFR2 gene cause syndromes characterized by facial and limb defects, including LADD Syndrome, Crouzon Syndrome, Beare-Stevenson Cutis Gyrata Syndrome, Pfeiffer Syndrome, Apert Syndrome, and Jackson-Weiss Syndrome (3-5). FGFR2 gene amplification and other mutations, as well as altered expression, have been observed in cases of gastric, endometrial, and breast cancer (6). FGFR2 has two primary isoforms, FGFR2IIIc (isoform1, also known as BEK) and FGFR2IIIb (isoform 3, also known as FGFR2b) that are generated through alternative spicing of the third immunoglobulin-like domain crucial for ligand binding. The isoforms differ in tissue distribution and biological activities (7,8). FGFR2IIIb is mainly detected in epithelial cells and can be overexpressed in estrogen receptor-positive breast cancer and gastric cancer (9-11). It preferentially binds to the ligands FGF7, FGF10, and FGF22, with subsequent receptor homodimerization activating downstream signaling pathways including PI3K/Akt and RAS-MAPK (12-14). When overexpressed, FGFR2IIIb promotes aberrant signaling, leading to tumor cell proliferation (15).