A correlation between cancer and hypercoagulability has been described for more than a century. Patients with cancer are at increased risk for thrombotic complications and the clotting initiator protein, tissue factor (TF), is possibly involved in this process. Moreover, TF may promote angiogenesis and tumor growth. In addition to TF, thrombin seems to play a relevant role in tumor biology, mainly through activation of protease-activated receptor-1 (PAR-1). In the present study, we prospectively studied 39 lung adenocarcinoma patients in relation to the tumor expression levels of TF and PAR-1 and their correlation with thrombosis outcome and survival. Immunohistochemical analysis showed TF positivity in 22 patients (56%), most of them in advanced stages (III and IV). Expression of PAR-1 was found in 15 patients (39%), most of them also in advanced stages (III and IV). Remarkably, no correlation was observed between the expression of TF or PAR-1 and risk for thrombosis development. On the other hand, patients who were positive for TF or PAR-1 tended to have decreased long-term survival. We conclude that immunolocalization of either TF or PAR-1 in lung adenocarcinoma may predict a poor prognosis although lacking correlation with thrombosis outcome.
