Thrombomodulin (1009)

Thrombomodulin is a transmembrane glycoprotein composed of 575 amino acids (molecular weight 75 kD with natural anticoagulant properties. It is normally expressed by a restricted number of cells, such as endothelial and mesothelial cells. In addition, synovial lining and syncytiotrophoblasts of human placenta also express thrombomodulin. Several immunohistochemical endothelial markers are currently available and anti-thrombomodulin serves as another such marker, staining blood and lymphatic channels consistently. Anti-thrombomodulin has demonstrated positivity in 100% of benign vascular tumors (pyogenic granuloma and hemangioma) and 94% of malignant vascular tumors (Kaposi’s sarcoma, angiosarcoma, and epithelioid hemangioendothelioma). Hence, anti-thrombomodulin serves as a sensitive marker for lymphatic endothelial cells and their tumors.1-2 There has also been recent interest in the use of anti-thrombomodulin as an immunohiostochemical marker for mesothelial cells and malignant mesotheliomas.3-8 Anti-thrombomodulin is immunoexpressed in a variety of other tumors including squamous cell carcinomas of the lung, synovial sarcoma, transitional cell carcinoma, renal cell carcinomas and thymomas.9,10