High extracellular fibrinolytic activity of tumors and control normal tissues

Abstract

In search of whether high extracellular proteolytic activity is a general tumor phenotype, we examined the levels of extracellular fibrinolytic activity due to plasminogen activation in the primary cultures of 10 lines of immunogenic and non-immunogenic transplanted sarcomas of mice. The levels of activity were compared with those of their normal control tissues, muscle and skin. Both the normal control muscle and skin, as well as all tumors had high and moderate levels of extracellular fibrinolytic activity. The data therefore do not support the hypothesis that high extracellular proteolytic (fibrinolytic) activity is either a general tumor phenotype, or a property which may offer significant advantage over normal cells for positive selection in tumor growth and invasiveness.