Circulating microRNA-34 family low expression correlates with poor prognosis in patients with non-small cell lung cancer

Abstract

BACKGROUND: To evaluate the association of plasma miR-34a/b/c expressions with the clinicopathological properties and the prognosis in non-small cell lung cancer (NSCLC) patients. METHODS: A total of 196 NSCLC patients were recruited in the study. Plasma sample and tumor tissue sample were collected. Total RNA was extracted from plasma and tissue samples, and microR-34a/b/c expression was evaluated by real-time polymerase chain reaction (PCR). RESULTS: MiR-34a and miR-34c in plasma were positively associated with that in tumor tissue (P<0.001 and P=0.001, respectively). Plasma miR-34a expression was negatively correlated with lymph node metastasis (P=0.002), also tissue miR-34a expression was negatively associated with lymph node metastasis (P=0.018). Furthermore, plasma miR-34a high expression was correlated with prolonged disease-free survival (DFS) (P=0.011) and overall survival (OS) (P=0.011) compared to low expression, and plasma miR-34c high expression could predict longer DFS (P=0.038) than low expression, while no correlation of plasma miR-34b with DFS and OS was discovered. In terms of tissue sample, worse DFS was associated with miR-34a (P=0.002) and miR-34c (P=0.032) low expressions compared with high expressions, and miR-34a (P<0.001), as well as miR-34c (P=0.003) high expressions were associated with longer OS than low expressions. Plasma miR-34a was correlated with prolonged DFS and OS in univariate Cox model, while it could not independently predict DFS and OS of NSCLC patients in multivariate Cox model. CONCLUSIONS: In conclusion, circulating miR-34a and miR-34c might be served as novel prognostic biomarkers in NSCLC patients.