title: Interaction of human tumor cells with human platelets and the coagulation system.
abstract: This paper reports studies on the interaction between human platelets, the plasma coagulation system, and two human tumor cell lines grown in tissue culture: Melanoma and breast adenocarcinoma. The interaction was monitored through the use of 125I-labelled fibrinogen, which measures both thrombin activity generated by cell-plasma interaction and fibrin/fibrinogen binding to platelets and tumor cells. Each tumor cell line activates both the platelets and the coagulation system simultaneously resulting in the generation of thrombin or thrombin-like activity. The melanoma cells activate the coagulation system through "the extrinsic pathway" with a tissue factor-like effect on factor VII, but the breast tumor seems to activate factor X directly. Both tumor cell lines activate platelets to "make available" a platelet-derived procoagulant material necessary for the conversion of prothrombin to thrombin. The tumor-derived procoagulant activity and the platelet aggregating potential of cells do not seem to be inter-related, and they are not specific to malignant cells.
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D001792:Blood Platelets / Q000502:physiology*; D001943:Breast Neoplasms / Q000473:pathology*; D002460:Cell Line; D002478:Cells, Cultured; D005167:Factor VII; D005170:Factor X; D005337:Fibrin / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006487:Hemostasis; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008545:Melanoma / Q000473:pathology*
chemical_list: D007457:Iodine Radioisotopes; D005167:Factor VII; D005170:Factor X; D005337:Fibrin; D005340:Fibrinogen