Prognostic significance of serum miRNA‐21 expression in human non‐small cell lung cancer

Abstract

Deregulation of microRNAs (miRNAs) plays important roles in tumor progression. The aim of this study was to investigate miR-21 expression in serum of non-small cell lung cancer (NSCLC) and its correlation with prognosis of NSCLC patients. Dysregulated miRNAs in NSCLC serum were identified by microarray. MiR-21 expression in NSCLC and control serum was detected by TaqMan RT-PCR assay. The correlation of serum miR-21 with clinicopathological factors of NSCLC patients was analyzed. Furthermore, the prognostic significance of serum miR-21 was analyzed by using Kaplan-Meier curves with log-rank tests and a Cox proportional hazard model. The level of miR-21 expression was higher in NSCLC serum samples than in control serum samples (P < 0.01). High serum miR-21 was significantly correlated with tumor-node metastases stage and lymph node metastasis of NSCLC patients (P = 0.016 and 0.026, respectively). The 3-year actuarial overall survival rates in NSCLC patients with high serum miR-21 expression (39.8%) was significantly shorter than those with low serum miR-21 expression (58.2%; P < 0.001). Furthermore, univariate and multivariate analyses for overall survival showed that serum miR-21 expression was an independent prognostic factor for NSCLC patients (P = 0.015, RR = 2.01, 95% CI: 1.78-3.26). Serum miR-21 expression might be useful as a prognostic marker for NSCLC patients.