Procoagulant and fibrinolytic activities of gastric and colorectal cancer.

Procoagulant activity (PA) and fibrinolytic activity (FA) were investigated in 14 specimens of gastric cancer (GC) and in 26 specimens of colorectal cancer (CC) and simultaneously, in samples of the normal mucosa obtained from the same organs. Histochemical localization of plasminogen activator was performed at the tumor borderline. The PA of the tumor extracts was in most cases lower than in the corresponding normal mucosa from GC as well as CC patients. The FA of the extracts of CC was also lower than that of normal mucosa. On the other hand, 11 of 14 cases with GC showed a significantly higher FA in the tumor extracts than that in the corresponding normal mucosa. The histochemical localization of plasminogen activator revealed that its activity is connected with small and medium-sized blood vessels, but not with the cells of the two kinds of cancer investigated. Morphological and histochemical findings from both kinds of cancer demonstrate that the FA of their extracts depends on the vascularity of specimens of the respective tumors.