ABSTRACT
The antimetastatic effect of heparin and warfarin was demonstrated by numerous investigations. In some experiments, heparin or warfarin treatment of mice with depressed Natural Killer (NK) reactivity was able to reduce the number of developed lung colonies, at least to the level observed in the control, nontreated mice. This residual antimetastatic activity of the anticoagulant agents may be explained by their effects on other processes involved in metastasis formation or by the persistence of some noneliminated NK cells. The antimetastatic effect of heparin in beige mice could be abrogated by further depression of their NK reactivity with antiasialo GM1 serum. Although the present study focused on the role of NK cells in the antimetastatic effects of anticoagulant drugs, it seems likely that fibrin deposition or platelet aggregation on the tumor cell surface could be protective against the destructive action of other cytotoxic effector cells.
