Upregulation of serum miR-494 predicts poor prognosis in non-small cell lung cancer patients.

OBJECTIVE: Emerging studies show that microRNAs (miRNAs) play a essential role in tumorigenesis. Deregulation of miR-494 is frequently observed in various human cancers including non-small cell lung cancer (NSCLC). However, little is known about the clinical significance of serum miR-494. The aim of this study was to investigate the diagnostic and prognostic value of serum miR-494 for NSCLC.

METHODS: We first compared miR-494 levels between NSCLC cell lines and lung bronchus epithelial cell line. A total of 90 NSCLC patients and 50 healthy controls were included in this study. MiR-494 levels were examined in serum samples by using real-time quantitative reverse transcription polymerase chain reactions. Association between serum miR-494 levels and the prognosis of NSCLC was further analyzed.

RESULTS: Our results showed that miR-494 was elevated in NSCLC cell lines. Serum miR-494 levels were significantly increased in patients with NSCLC compared to healthy controls. Area under receiver operating characteristic (ROC) curve was 85.4%. In addition, serum miR-494 levels decreased remarkably when patients received effective therapy. High serummiR-494 levels were significantly associated with higher incidence of lymph node metastasis, advanced clinical stage and higher histological grade. Moreover, survival analysis demonstrated that patients in the high serum miR-494 group had a poorer 5 year overall survival and disease free survival compared with the patients in the low serum miR-494 group. Multivariate analysis showed that serum miR-494 was an independent risk factor.

CONCLUSIONS: In conclusion, serum miR-494 was significantly elevated in NSCLC patients and closely correlated with poor clinical outcome, indicating that serum miR-494 might be a useful diagnostic and prognostic marker for NSCLC.