THBD and neoplasm: Reduction of anticoagulant substances[5]: vascular endothelial cells are destroyed by malignant tumors, resulting in downregulation of factors that antagonize thrombin or coagulation factors, such as thrombomodulin (TM) and antithrombin III; tumor cells can trigger mononuclear macrophages to secrete TNF, IL-1, and tissue factor pathway inhibitor (TFPI) with downregulated oxygen radicals, leading to downregulation of protein C system anticoagulation; massive anticoagulant substances are consumed.