Identification of a plasminogen activator derived from nasopharyngeal carcinoma.

The activity of plasminogen activator (PA) in tissue extracts from nasopharyngeal carcinoma (NPC) was determined by means of the fibrin plate method. Development of PA activity was observed in 16 out of 25 cases investigated. Furthermore, using tissue extract of NPC with PA activity, characterization and identification of the activator were carried out by means of electrophoretic analysis, fibrin zymography and immunological analysis. The molecular weight of this PA was found to be 38,000 daltons. Additionally, a urokinase type of plasminogen activator was contained in the tissue extracts.