Expression of thrombomodulin in esophageal squamous cell carcinoma and its relationship to lymph node metastasis

Thrombomodulin (TM) was originally identified on the endothelium, and acts as a natural anticoagulant. However, TM was also expressed in the squamous epithelium (Am J Clin Pathol 88:465-411,1987). In the present study, we examined TM expression in the primary lesions of 106 patients with esophageal squamous cell carcinoma (SCC) and in the lymph node metastatic lesions of 59 patients immunohistochemically. In the metastatic lesions of 59 patients, 41 (69%) showed decreased TM expression, 18 (31%) showed no change, and none of the cases (0%) showed an increase. Tumor cells positive for TM expression were significantly rarer in the metastatic lesions than in the primary tumors (p<0.0001). Also in the esophageal SCC cell lines, positive TM expression was observed in the immunocytochemistry, Western blot analysis and Northern bot analysis. Anticoagulant activity was also disclosed in the cell lines by TM activity assay.