Localization of plasminogen activators and their inhibitor in squamous cell carcinomas of the head and neck.

Abstract

Plasminogen activators (PAs) and their inhibitors are thought to play an important role in tumor invasion and metastasis. However, there have been few reports in which histologic localization of PAs has been demonstrated in head and neck tumors. We examined the patterns of expression of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), and vitronectin in head and neck squamous cell carcinomas using immunohistochemical techniques. We also studied the correlation between the immunohistologic expression of these fibrinolytic proteins and the clinical staging of the tumor. Of 28 tumor specimens, 15 (54%) showed immunoreactivity for u-PA; 8 (36%), for t-PA; and 23 ( 82%), for PAI-1. There was a significant correlation between PAI-1 expression and the extent of the primary tumor. The present study demonstrates the existence and possible pathophysiologic significance of u-PA and PAI-1 in squamous cell carcinomas of the head and neck.