High miRNA-221 expression is associated with poor overall survival in patients with non-small cell lung cancer

Objective: The objective of this study was to investigate miRNA-221 expression in non-small cell lung cancer (NSCLC) and to determine the correlation between miRNA-221 expression and overall survival. Methods: Clinical data pertaining to 151 NSCLC patients who underwent complete tumor resection surgery between January 2012 and December 2015 were retrospectively analyzed, and miRNA-221 expression was detected via quantitative reverse transcription polymerase chain reaction (qRT-PCR). The relationship between miRNA-221 expression and patient clinical data, including overall survival (OS), was analyzed. Results: The expression level of miRNA-221 was significantly higher in NSCLC tissues than in adjacent non-tumor tissues (P<0.05). Significantly higher miRNA-221 expression levels were observed in patients >= 50 years of age and with advanced disease (P<0.05). Univariate Cox regression analysis showed that clinical stage (OR=1.97, 95% CI: 1.14-2.67), pathological type (OR=2.55, 95% CI: 1.77-5.12), tumor size (OR=1.34, 95% CI: 1.01-2.14) and miRNA-221 expression (OR=3.08, 95% CI: 1.76-6.31) were risk factors for shorter OS. Multivariate Cox regression analysis showed that clinical stage (OR=3.35, 95% CI: 1.67-5.05), tumor size (OR=2.02, 95% CI: 1.03-3.24) and miRNA-221 expression (OR=2.58, 95% CI: 1.41-64.85) were independent risk factors for shorter OS. The median OS time in the low miRNA-221 expression group was 41 months (95% CI: 36.22-45.78), which was significantly higher than that in the high miRNA-221 expression group (25 months, 95% CI: 5.85-35.15, P=0.011). Conclusion: Our data indicate that higher miRNA-221 expression levels are associated with shorter OS in patients with NSCLC and that miRNA-221 may be a molecular marker of patient prognosis in NSCLC.