Abnormalities of blood coagulation in patients with cancer. Mononuclear cell tissue factor generation

Activation of blood coagulation, as characterized by the occurrence of disseminated intravascular coagulation, increased levels of plasma FPA, and the local deposition of fibrin, is common in both experimental animals and patients with malignant tumors. Many mechanisms have been proposed for the mediation of this response to tumors, including tumor-associated proteases, platelet adherence to tumors, surface activation of blood coagulation by tumor cells, and activation of coagulation by tissue factor derived from either tumor tissue or reactive leukocytes. We have investigated the hypothesis that MTF generation may contribute to increased fibrin generation in cancer patients. Plasma FPA levels and in vitro unstimulated MTF generation were measured simultaneously in samples obtained from 35 patients with lung cancer. FPA levels were significantly elevated in these patients as compared to a group of 20 normal volunteers (p = 0.03). Although unstimulated MTF generation showed considerable variability in both the patients and the normal volunteers, a high degree of correlation was observed between simultaneous levels of FPA and MTF regardless of whether MTF was expressed per cell (r = 0.83), per monocyte (r = 0.95), or per volume of peripheral blood (r = 0.96). MTF generation was also significantly decreased in a group of patients receiving sodium warfarin (p less than 0.001). These results suggest a potential role for MTF generation in the activation of blood coagulation in neoplasia and also suggest the possibility that inhibition of MTF generation by warfarin may be partially responsible for the decreased FPA values previously reported in anticoagulated cancer patients.