Fibrinolysis associated with human neoplasia: Production of plasminogen activator by human tumours

The plasminogen-dependent fibrinolytic activity of several human tumours has been studied. The following neoplastic tissues, which were obtained from cancer patients by either surgery or biopsies, were examined: cervical, mammary, prostatic, ovarian, lung carcinomas, melanoma, basalioma. Fibrinolysis was measured in lysates either of tumour tissue specimens or of respective cell cultures. This measurement was based on release of radioactivity from 125I-fibrin-coated Petri dishes. All examined tumours showed elevated levels of plasminogen-dependent fibrinolytic activity. However, normal control tissues had little or no activity. These results indicate that the fibrinolysis might be useful in differentiating between malignant and normal tissues.