Occurrence of components of fibrinolytic pathways in situ in laryngeal cancer.

Malignancy is characterized by the occurrence of components of coagulation reaction pathways in situ within tumor tissues detectable immunohistochemically. However, tumors vary in the details of this coagulation-cancer interaction. We have previously described tumor cell-associated tissue factor (TF), factor (F) VII, and F X in laryngeal carcinoma tissues. Fibrinogen and F XIIIa were found in the tumor connective tissue. Tissue factor pathway inhibitor (TFPI) occurred in the tumor connective tissue and on microvascular endothelial cells and normal squamous epithelial cells but not in the tumor cells. Fibrin (thrombin-cleaved fibrinogen) existed at the host-tumor interface and the margins of tumor nodules consistent with an active tumor cell-associated clotting pathway in this tumor type. Studies were extended here to detect components of fibrinolytic pathways. Plasminogen and tissue plasminogen activator (t-PA) were detected on laryngeal tumor cells, particularly in more well-differentiated cases. Low-molecular-weight urokinase plasminogen activator (LMW u-PA) was primarily a feature of more undifferentiated laryngeal carcinoma cells. Staining to a lesser extent was found for high-molecular-weight u-PA (HMW u-PA) on tumor cells and various normal cell types in the tumor tissue. Relatively weak and variable tumor cell staining was found for plasminogen activator inhibitors (PAI) 1, 2, and 3. Trace staining was found for u-PA receptor (u-PAR) in differentiated tumor cells. The significance of coagulation and fibrinolytic pathways present in situ to the economy of laryngeal carcinoma remains to be determined.