Investigation of the procoagulant activity present in ascitic fluid and serum of mice bearing the Landschütz ascites carcinoma.

The direct procoagulant activity (PCA) of murine tumour cells was found to be more than three orders of magnitude greater than an equivalent concentration of either resident or Corynebacterium parvum-elicited, exudate peritoneal cells. Similarly, a soluble PCA was detected in the extracellular culture medium of only the tumour cells. Studies on the procoagulant nature of the serum and ascitic fluid of tumour-bearing animals suggested that the ascitic fluid may contain a unique PCA factor(s). This activity could not, however, be resolved from inherent procoagulant factors, either by gel filtration or ammonium sulphate fractionation, and a more specific assay for, say, a single enzymic reaction in the coagulation cascade would be required to identify the tumour-associated activity.