Abstract
Various anticoagulant, antiplatelet, and fibrinolytic agents have been found to be effective in reducing metastatic growth of experimental animal tumors. This effectiveness is attributed to the requirement for hemostatic factors in the implantation and growth of metastases. However, clotting and platelet factors are also present at the site of a primary tumor, the Walker 256 carcinosarcoma. Yet maximally tolerated doses of heparin or warfarin did not affect the primary growth of this rat tumor.