RESUMO
OBJECTIVE: MiRNAs play crucial roles in progression of cancer. However, the underlying mechanisms of miRNAs in non small cell lung cancer are still poorly understood. The aim of this study was to investigate the expression level of microRNA-126 (miR-126) and microRNA-133b (miR-133b) and also their association with clinicopathological features in patients with non small cell lung cancer (NSCLC). METHODS: Total RNA was purified from NSCLC tissues and adjacent non-tumor tissues and then quantitative real-time PCR (qRT-PCR) was used to evaluate the expression rate of microRNAs. Furthermore, the association of miR-126 and miR-133b level with clinicopathological features and prognosis were evaluated. RESULTS: Our findings showed that expression of miR-126 was decreased in NSCLC tissues compared with adjacent non-tumor tissues. On the other hand, a lower expression of miR-133b was seen in NSCLC tissues when compared with adjacent non-tumor tissues. In term of miR-126, our results showed that miR-126 was associated with tumor stage and lymph nodes metastasis (P<0.05). In term of miR-133b, our finding indicated that decreased expression of miR-133b was correlated with advanced tumor stage and lymph nodes metastasis (P<0.05). Kaplan-Meier analysis and log-rank test indicated that patients with low expression of miR-126 and miR-133b had a shorter overall survival (log-rank test; P<0.05). Multivariate Cox proportional hazards model revealed that low expression of miR-126 and miR-133b, advanced tumor stage and lymph nodes metastasis were independent prognostic factors for overall survival of NSCLC patients. CONCLUSIONS: These findings suggested that miR-126 and miR-133b might play a key role in the progression and metastasis of NSCLC and would be applied as a novel therapeutic agent.