STUDIES ON PLASMINOGEN ACTIVATOR ACTIVITY IN CANCEROUS TISSUES OF THE BLADDER

Abstract

The localization of fibrinolytic activity and plasminogen activator concentration in normal and cancerous tissues of the bladder were investigated by either Todd's method or Astrup and Albrechtsen's method. Specimens were obtained from 28 patients who had undergone partial cystectomy for baldder cancer; 25 cases of transitional cell carcinoma and 3 cases of squamous cell carcinoma. The results obtained are as follows:
1. Lysis areas of fibrin film which were produced by an activator of plasminogen could be demonstrated in relation to the injured or destroyed epithelium and cancer cells, and to the venous channels in the muscular and serosal layers. However, the venous channels distributing over the tumor stroma showed less fibrinolytic activity. Intact bladder epithelium and cancer cells were fibrinolytically inactive.
2. The plasminogen activator concentration of the cancerous tissues of Grade II to IV was significantly higher than that of the corresponding normal mucous membranes and of the Grade I cancerous tissues, p<0.05.
3. Analysis of the literature concerning fibrinolysis activators and inhibitors in cancerous tissues and the present findings permit the suggestion that the canerous tissues are maintained in the depressed fibrinolytic condition due to an excess of the inhibitors over the activators and this condition may contribute to the growth of cancer.