ABSTRACT
All components of hemostasis, that is, the endothelial cells, the platelets, and the blood coagulation-fibrinolytic system, might be involved in malignancy. While blood coagulation, primarily fibrin formation and platelet aggregation, plays an important role in the arrest of cancer cells from a metastatic spread as well as in tumor angiogenesis, fibrinolysis is a critical step in the release of neoplastic cells from the primary tumor. In the phase, tumor cells are released into blood circulation by the action of plasmin, the key enzyme of the fibrinolytic system. Plasmin may be formed via activation of plasminogen by plasminogen activators synthesized by either tumor cells or endothelial cells. The tumor cells are covered by a fibrin-envelope and are attached to platelets, leukocytes, and to endothelial cells. Proteinases secreted by tumor cells can initiate prothrombin activation, and as a consequence, the increased amount of thrombin favors the arrest of metastatic tumor cells as well as angiogenesis.
