Fibroblast growth factor 8 (isoform b) (FGF8b)

Fibroblast growth factor 8 isoform b (FGF8b) is a secreted signaling protein belonging to the fibroblast growth factor family, specifically the FGF8/17/18 subfamily. It is produced through alternative splicing of the FGF8 gene and is recognized as the most biologically active and oncogenic isoform due to its high affinity for FGF receptors (FGFRs), particularly FGFR2 and FGFR3 (UniProt P55075). In normal physiology, FGF8b plays a critical role in embryonic development, including the patterning of the midbrain, hindbrain, and limbs (PubMed: 15561703). However, its aberrant overexpression is strongly linked to the progression of hormone-dependent cancers, such as prostate and breast cancer, where it promotes tumor cell proliferation, survival, and angiogenesis (PubMed: 11507054). Therapeutic strategies targeting FGF8b include the development of neutralizing monoclonal antibodies and ligand traps, such as FP-1039, designed to sequester the protein and prevent its interaction with cognate receptors (ClinicalTrials.gov: NCT01868438). While targeting FGF8b holds promise for oncology, potential safety concerns include interference with normal tissue repair and developmental processes (PubMed: 21813755).

Other names

Androgen-induced growth factorAIGFHeparin-binding growth factor 8HBGF-8Fibroblast growth factor 8b

Sequestration of the FGF8b ligand using soluble receptor decoys (ligand traps) or neutralizing antibodies to inhibit downstream signaling through fibroblast growth factor receptors (FGFRs).