Down-regulation of miR-133a as a poor prognosticator in non-small cell lung cancer

• miR-133a expression was down-regulated in NSCLC tissues compared to normal lung tissues.
• miR-133a expression level was negativity correlated with the status of N classification, clinical stage and MMP-14 status.
• Patients with lower levels of miR-133a expression had poorer OS rates than those with higher levels of miR-133a expression.
• miR-133a expression was an independent prognostic factor for OS in NSCLC patients.

miR-133a has been demonstrated to play an important role in tumor progression. The aim of present study was to analyze the correlation between miR-133a expression level and clinicopathologic features and its prognostic significance in non-small cell lung cancer (NSCLC). The expression of miR-133a in 104 pairs of human lung cancer tissues and adjacent normal lung tissues were analyzed by qRT-PCR. Here we show that miR-133a was down-regulated in NSCLC. The levels of miR-133a were negatively correlated with the status of N classification (N0–N1 vs. N2–N3, P = 0.000), clinical stage (I–II vs. III–IV, P = 0.010) and MMP-14 expression (High vs. Low, P = 0.012). The patients with low miR-133a expression had shorter survival time than those with high miR-133a expression. Multivariate analysis indicated that the level of miR-133a expression was an independent prognostic indicator (P = 0.012) for the survival of patients with NSCLC. In conclusion, decreased expression of miR-133a might be a potential unfavorable prognostic factor for patients with NSCLC, and further studies would be needed to prove our findings.