Pancreatic cancer is one of the most prothrombotic malignancies. Plasma clot properties may be altered in patients with pancreatic cancer, and circulating tissue factor (TF) may play an important role. We applied a modified plasma clot formation assay (only CaCl2 and phospholipids were added to initiate clotting) and a standard clotting assay (lipidated TF was also added) to investigate whether plasma clot properties are altered in pancreatic cancer patients (n = 40, 23 female) compared to sex-matched healthy controls. The modified assay was also performed in the presence of a TF blocking antibody. With this modified assay, we detected an increased plasma clot formation rate (Vmax) and an increased delta absorbance (ΔAbs, indicating fibrin fiber thickness) in patients compared to controls. These differences were not detected with the standard clotting assay. Following addition of a TF blocking antibody in in our modified assay, Vmax decreased significantly in patients only, ΔAbs significantly decreased in patients and in healthy controls, the lag phase did not change, and the time to peak fibrin generation increased in patients only. Taken together, these findings indicate the presence of a prothrombotic state in pancreatic cancer patients, which depends on TF and is detectable with our modified assay but not with a standard clotting assay.
Keywords: pancreatic cancer; plasma clot formation; tissue factor.