Herstatin, Human

dry ice

Oncology

Herstatin a member of the epidermal growth factor (EGF) receptor family of receptor tyrosine kinases. Herstatin has no ligand binding domain of its own and therefore cannot bind growth factors. However, it does bind tightly to other ligand-bound EGF receptor family members to form a heterodimer, stabilizing ligand binding and enhancing kinase-mediated activation of downstream signalling pathways, such as those involving mitogen-activated protein kinase and phosphatidylinositol-3 kinase. Allelic variations at amino acid positions 654 and 655 of isoform a (positions 624 and 625 of isoform b) have been reported. Amplification and/or overexpression of this gene has been reported in numerous cancers, including gastric cancer, breast and ovarian tumors. Alternative splicing results in several additional transcript variants.