Increased circulating levels of thrombin-activatable fibrinolysis inhibitor in lung cancer patients

Impairment of fibrinolytic function plays an important role in the mechanism of thrombotic disorders in cancer patients. This study assessed the circulating level of thrombin-activatable fibrinolysis inhibitor in patients with lung cancer and its expression by several lung cancer cell lines. The plasma concentrations of thrombin-activatable fibrinolysis inhibitor were significantly increased in lung cancer patients compared to healthy subjects. The concentration of thrombin-activatable fibrinolysis inhibitor was particularly higher in patients with small cell carcinoma compared to those with adenocarcinoma or squamous cell carcinoma, and in cancer patients that responded to chemotherapy compared to non-responders. In vitro studies showed more expression of thrombin-activatable fibrinolysis inhibitor in small cell carcinoma than in adenocarcinoma cell lines and more expression in lung cancer cell lines sensitive to anti-cancer agents than in resistant cell lines. This study suggests that thrombin-activatable fibrinolysis inhibitor, in part secreted from lung cancer cells, may play a role in the pathogenesis of thrombotic disorders in lung cancer patients.