CD109 is a glycosyl phosphatidylinositol (GPI)linked glycoprotein that localizes to the surface of platelets, activated Tcells, and endothelial cells. CD109 is expressed in many malignant tumors, including various squamous cell carcinomas and adenocarcinomas, and plays a role as a multifunctional coreceptor.CD109 reportedly associates with transforming growth factor (TGF)beta receptors and negatively regulates TGFbeta signaling in keratinocytes. Additionally, CD109 is potentially related to signal transducer and activator of transcription3 signaling and aberrant cell proliferation. - Proteine/Peptide