Thrombus formation in cancer patients using autopsy materials: an immunohistochemical analysis.

BACKGROUND: Cancer-associated thrombosis (CAT) is a well-known complication of malignant tumors. It has been predominantly reported in mucin (MUC)-producing adenocarcinomas, with MUC secreted by the tumor thought to be involved in the thrombotic mechanism. However, studies comparing tumor and thrombus areas are scarce. METHODS: In this study, we examined the immunohistochemical characteristics of 18 autopsy specimens of tumor and thrombus sections (CAT) and control specimens of 25 tumors without thrombus and 16 thrombi without tumors. Immunohistochemistry was performed using antibodies associated with coagulation and MUC, including tissue factor (TF), thrombin, MUC2, MUC5AC, and MUC6. RESULTS: It was revealed that TF was predominantly positive in the tumor sections of CAT compared with tumors without thrombus (P<0.0001), and MUC2 expression was significantly higher in thrombus sections of CAT than that in thrombi without tumors (P<0.0001). In the thrombus region, TF positivity was inversely correlated with MUC2 positivity. CONCLUSIONS: These results suggest that the expression of TF in tumor tissues is involved in the pathogenesis of CAT, and furthermore, that MUC2 contributes to thrombus formation in CAT via a pathway other than TF. In the future, these immunohistochemical analyses will help predict CAT in cancers and detect hidden cancers in patients with thrombosis.