Expression of tissue factor and tissue factor pathway inhibitor in situ in laryngeal carcinoma

The blood coagulation mechanism may support tumor progression by several mechanisms including promotion of cell proliferation and angiogenesis. Immunohistochemical procedures were applied to AMeX-fixed sections of twelve cases of squamous cell carcinoma of the larynx obtained at surgical resection to determine the presence and distribution of tissue factor (TF), tissue factor pathway inhibitor (TFPI), other coagulation factors, fibrinogen, and fibrin in situ. TF antigen was present in normal squamous epithelial cells and tumor cells, predominantly in immature tumor cells in the vicinity of the host-tumor interface. Tumor cells stained also for factors VII and X. Staining for TFPI antigen was demonstrated in the connective tissue stroma adjacent to the tumor, in microvascular endothelial cells, and in normal squamous epithelial cells. Fibrinogen and factor XIIIa were distributed throughout the tumor connective tissue stroma. Fibrin (thrombin-cleaved fibrinogen) was detected at the host-tumor interface and along the margins of tumor nodules. Tumor cells in carcinoma of the larynx express a functional, TF-initiated pathway of blood coagulation. Interpretation of these findings together with the results of clinical trials of inhibitors of TF-induced coagulation activation versus effects of inhibitors of TF expression suggest novel approaches to the experimental therapy of laryngeal carcinoma.