Cancer procoagulant in serum of rats during development of experimental epithelioma

The activity of cancer procoagulant (CP) during the development of Guérin epithelioma was studied in the blood of Wistar rats. Blood was collected from the carotid artery and, after clotting, proteins adsorbing on aluminum hydroxide were removed from the serum. Then procoagulant activity was determined in the test system without factor VII by means of substrate S-2222 specific for factor Xa. A statistically significant increase in the activity of CP in serum was detected, coinciding with the period of intensive tumor growth (15th-25th day of disease).