Abstract
BACKGROUND: MicroRNAs were important regulators of tumors and the expression of miRNA-221 was associated with malignant proliferation and invasion in many tumors. The aim of this study is to explore the expression of miRNA-221 in non-small cell lung cancer (NSCLC) tissues and its correlation with prognosis. METHODS: We retrospectively analyzed the clinical characteristics of 117 NSCLC patients who underwent surgery in our hospital from November 2005 to January 2007. Real-time PCR was used to detect the expression of miRNA-221. Chi-square test was utilized to analyze the relationship between miRNA-221 expression and clinicopathologic features. Survival curves were plotted by using the Kaplan-Meier method and compared by the Log-rank test. A Cox proportional hazard regression model was applied to examine the joint effect of covariants. A P-value less than 0.05 was evaluated as statistically significant. RESULTS: The patients were divided into two groups according to the relatively expression of miRNA-221. No statistically significance was observed between the expression of miRNA-221 and the clinicopathologic parameters, including gender (χ(2)=0.070, P=0.791), histology (χ(2)=0.414, P=0.520), p-TNM stage (χ(2)=0.068, P=0.794) and history of smoking (χ(2)=0.206, P=0.650). Kaplan-Meier analysis showed that high expression of miRNA-221 was closely associated with a shorter survival time (P<0.001). Finally, both univariate and multivariate analyses demonstrated that high miRNA-221 expression might be a poor prognostic marker of NSCLC patients. CONCLUSIONS: Our results indicated that down-regulation of miRNA-221 was associated with poor prognosis of patients with NSCLC. MiRNA-221 may serve as a molecular prognosis marker for patients with NSCLC.