Reduced survival in patients with early-stage non-small-cell lung cancer is associated with high pleural endothelial progenitor cell levels

OBJECTIVES: Endothelial progenitor cells are capable of contributing to neovascularization in tumours. In patients with either malignant or transudative pleural effusion, we tested the presence of pleural endothelial progenitor cells. We also measured the number of endothelial progenitor cells in post-surgery pleural drainage of either patients with early non-small-cell lung cancer or control patients with benign lung disease undergoing pulmonary resection. The prospective influence of post-surgery pleural-drainage endothelial progenitor cells on cancer recurrence/survival was investigated. METHODS: Pleural endothelial progenitor cell levels were quantified by fluorescence-activated cell sorting analysis in pleural effusion of 15 patients with late-stage non-small-cell lung cancer with pleural involvement and in 15 control patients with congestive heart failure. Also, pleural-drainage endothelial progenitor cells were measured in pleural-drainage fluid 48 h after surgery in 64 patients with earlystage non-small-cell lung cancer and 20 benign lung disease patients undergoing pulmonary resection. Cancer recurrence and survival was evaluated in patients with high pleural-drainage endothelial progenitor cell levels. RESULTS: The number of pleural endothelial progenitor cells was higher in non-small-cell lung cancer pleural effusion than in transudative pleural effusion. Also, pleural-drainage endothelial progenitor cell levels were higher in patients with non-small-cell lung cancer than in patients with benign lung disease undergoing pulmonary resection (P < 0.05). Non-small-cell lung cancer patients with high pleural-drainage endothelial progenitor cell levels had a significantly 4.9 higher rate of cancer recurrence/death than patients with lower pleural-drainage endothelial progenitor cell levels, irrespective of confounders. CONCLUSIONS: Endothelial progenitor cells are present in the pleural effusion and are higher in patients with late-stage non-small-cell lung cancer with pleural involvement than in congestive heart failure patients. Endothelial progenitor cell levels are higher in the postsurgery pleural drainage of patients with non-small-cell lung cancer than in non-neoplastic pleural-drainage fluid. High pleural-drainage endothelial progenitor cell levels in patients undergoing pulmonary resection for early non-small-cell lung cancer predict an increased risk of cancer recurrence and death.