Osteopontin combined with CD44v6, a novel prognostic biomarker in non-small cell lung cancer undergoing curative resection.

BACKGROUND Osteopontin (OPN) is identified as one of the leading genes that promote the metastasis of malignant tumor through binding to CD44v6 and integrin. The purpose of the current study was to assess the prognostic significance of OPN and CD44v6 in patients with non-small cell lung cancer (NSCLC). METHODS Tissue microarray was used to detect the expression of OPN and CD44v6 in 159 NSCLC patients undergoing complete pulmonary resection in our hospital between 2003 and 2006. The correlations among OPN, CD44v6, and clinicopathologic data were analyzed using χ(2) testing analysis. The prognostic values of OPN and CD44v6 were evaluated by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. RESULTS OPN and CD44v6 were both independent predictors for overall survival and disease-free survival. When OPN and CD44v6 were considered together, the predictive range was extended and the sensitivity was improved, especially for those patients with stage I NSCLC. The 6-year overall survival and disease-free survival rates in OPN+ or CD44v6+ patients were 49.1% and 39.6%, respectively, which were significantly lower than those of OPN-/CD44v6- patients (64.4% and 47.7%, respectively), and were higher than those of OPN+/CD44v6+ patients (16.4% and 14.8%, respectively). Stratification into OPN+/CD44v6+, OPN+ or CD44v6+, or OPN-/CD44v6- groups, based on the expression OPN and CD44v6, could efficiently predicted outcomes (p < 0.001) of NSCLC patients. CONCLUSIONS The combination of OPN and CD44v6 is a valuable independent predictor of tumor recurrence and survival in NSCLC patients.