HGFNK potently inhibits tumor growth in vivo by increasing tumor cell apoptosis without affecting the proliferation rate of tumor cells. Taken together, the antitumor activity of HGF NK in vivo is at least partly mediated through an antiangiogenic activity. Nearly two decades ago, PF was the first hemostatic protein demonstrated to be an inhibitor of angiogenesis in vivo. One mechanism for the initial endothelial cell inhibition following platelet secretion is that PF blocks heparinlike glycosaminoglycans that function as critical, low Silver sulfadiazine affinity receptors for heparinbinding endothelial growth factors on the surface of endothelial cells. Further, a heparinindependent pathway of PF inhibition of endothelial cell growth exists.The endothelial cell stimulatory activity of epidermal growth Ciclopirox factor and VEGFA, endothelial mitogens that lack heparin affinity, is susceptible to PF inhibition. TSP may readjust growth factor and integrin signaling pathways between endothelial cells and the fibrin clot and prevent endothelial cell motility induced by fibrin.TSP stimulates endothelial cell adhesion and spreading but blocks the chemokinetic response of endothelial cells to bFGF. Cryptic fragments derived from coagulation and fibrinolytic proteins that suppress angiogenesis are indicated in bold red.Fibrinolytic pathway inhibitors that regulate angiogenesis are also printed in red.Coagulation cascade and fibrinolytic pathway inhibitors are indicated by a dashed arrow.PAI is maintained in an active conformation in complexes with vitronectin within platelet agranules but is less effective in the inhibition of the endothelial cell membraneassociated plasminogen activator. By limiting plasmin generation within the clot structure, PAI can suppress angiogenesis and amacroglobulin. Domain of HMWK also inhibits endothelial cell proliferation and is antiangiogenic on the chicken chorioallantoic membrane to yield thrombin and a twokringle aminoterminal domain. Thrombin then cleaves fragment of prothrombin into singlekringle fragment and fragment.Thrombin induces angiogenesis in vivo via cleavage of the tethered ligand of the thrombin receptor on endothelial cells without the requirement for fibrin formation. Simultaneously, these two aminoterminal kringle domains of prothrombin are released.Fragment and fragment of prothrombin inhibit the proliferation of endothelial cells in vitro and angiogenesis in vivo. Thus, the stimulatory effects of thrombin on endothelial cells would be antagonized by kringle byproducts released upon activation of prothrombin.This inactivation is very inefficient when coagulation factors are bound to the anionic phospholipid surface of activated platelets and endothelial cells.ATIII thus serves an important physiologic role in limiting the extent of an evolving clot to the area of vascular injury.Thrombin and neutrophil elastase can cleave the thrombinbinding site of ATIII becomes a potent inhibitor of endothelial cell proliferation in vitro and angiogenesis in vivo. Thus, the angiogenic activity of thrombin generated at the site of clotting may be balanced not only by fragment and of prothrombin but also through production of antiangiogenic ATIII.Fibrin monomers selfassemble at the site of vessel injury and enmesh the adhered platelets, migrationinhibited endothelial cells, and the exposed subendothelial matrix.Along with binding of latent regulators of plasminogen activation, fibrin also displays high affinity binding for bFGF, delivered by platelets.In vitro, fibrin acts as a scatter factor on confluent endothelial cells, an effect that would be counterproductive during hemostasis and therefore must be initially counteracted.