Expression of microRNA miR-126 and miR-200c is associated with prognosis in patients with non-small cell lung cancer.

MicroRNAs (miRNAs) are short non-coding RNAs that exert a critical influence on tumorigenesis through post-transcriptional modification and are considered to be potential biomarkers for the diagnosis or prognosis of various cancers. Although several miRNAs have been proposed as relevant biomarkers for non-small cell lung cancer (NSCLC), detailed working mechanisms and validated prognostic significance of these miRNAs remain controversial. In this study, we evaluated expression levels of miRNA-126 (miR-126) and miR-200c in 72 NSCLCs and 30 benign lung tissues by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and analyzed the correlation of miRNA expression with a variety of clinicopathological factors and patient survival. Compared with the benign control group, miR-126 expression was significantly downregulated in NSCLCs (p < 0.001), while miR-200c expression was significantly upregulated in NSCLCs (p < 0.001). The expression of miR-126 was significantly higher in NSCLCs with a tumor size of ≤3 cm than in those with a tumor size of >3 cm (p = 0.026). There were no other significant associations between miRNA expression and clinicopathological features. In univariate survival analysis for all NSCLC patients, high miR-200c expression (p = 0.037), large tumor size (p = 0.026), and lymphovascular invasion (p = 0.012) were significantly correlated with worse overall survival. High miR-126 expression was significantly associated with favorable prognosis only in patients with adenocarcinoma (p = 0.033). In multivariate analysis, miR-200c and tumor size remained as independent prognostic factors. Our results suggest that miR-126 might play tumor-suppressive and miR-200c an oncogenic role, and these miR's are potential prognostic biomarkers for NSCLC.