Serum KL-6 Levels in Lung Cancer Patients With or Without Interstitial Lung Disease

Background: It is not known whether lung cancer patients with interstitial lung disease (ILD) might have higher serum levels of KL-6, a high molecular weight glycoprotein classified as a polymorphic epithelial mucin. In addition, prognosis of these patients with elevated serum KL-6 levels might be poorer than that with normal KL-6 levels, but it has not been well clarified. Methods: Serum KL-6 levels in 273 lung cancer patients with or without ILD, and prognostic significance of elevated serum KL-6 levels in these patients were studied using uni- and multivariate analyses. Results: Serum KL-6 levels were elevated (> 500 U/ml) in 73.5% of lung cancer patients with ILD and in 33.7% of those without ILD. Serum KL-6 levels in lung cancer patients with ILD were significantly higher than those without ILD. In lung cancer patients with ILD, elevated serum KL-6 has no prognostic significance, but in those without ILD, however, it was one of the unfavorable prognostic factors. Conclusions: Elevated serum KL-6 levels can be observed in lung cancer patients both with and without ILD. Having ILD has strong prognostic impact in patients with lung cancer. In those without ILD, however, elevated KL-6 levels may be related to poor prognosis. J. Clin. Lab. Anal. 24:295-299, 2010. (C) 2010 Wiley-Liss, Inc.