Cancer cell procoagulants and their pharmacological modulation.

Cancer cells may promote fibrin formation in the tumor microenvironment through availability of procoagulant activities which are mainly of two types: tissue thromboplastin-like or direct activator of coagulation factor X. The pharmacological modulation of these activities could be potentially important in the control of metastasis growth. However, very limited information is available so far on this issue; it has recently been shown that the direct activator of coagulation factor X is a vitamin K-dependent activity which is depressed by warfarin treatment, not by anticoagulation with heparin or defibrinating enzymes. Whether the inhibition of this peculiar cancer procoagulant is involved in the antimetastatic activity of warfarin is a stimulating hypothesis which needs to be further substantiated.