CD109,also named as CPAMD7,is a member of the alpha2-macroglobulin/complement superfamily. It is a glycosylphosphatidylinositol (GPI)-linked cell surface glycoprotein of approximately 170kd which is found on the cell surface of platelets,activated T-cells,and endothelial cells. CD109 binds to and negatively regulates signaling of transforming growth factor beta (TGF-beta). CD109 has been identified as part of the TGF-beta receptor system in human keratinocytes. Up regulation of CD109 expression has been observed in several different types of tumor. Multiple transcript variants encoding different isoforms have been found for CD109. The antibody can recognize all these 4 isoforms.