Role of deregulated microRNAs in non-small cell lung cancer progression using fresh-frozen and formalin-fixed, paraffin-embedded samples.

Non-small cell lung cancer (NSCLC) is responsible for the highest number of cancer-associated mortalities worldwide, and the five-year survival rate is <15% following the initial diagnosis. MicroRNAs (miRNAs) serve important functions in a number of human diseases, including cancer. The present study investigated the expression status, clinical relevance and functional role of miRNA in NSCLC. miRNA expression profiling was performed in lung adenocarcinoma and adjacent unaffected lung tissues using 47 groups of fresh-frozen (FF) and 45 of formalin-fixed, paraffin-embedded (FFPE) samples from 11 pulmonary bulla. miR-21, -30e, -363 and -623 were further examined for differential expression in two independent cohorts. Other miRNAs, including miR-5100 and miR-650, were upregulated, while miR-10a and -26b were downregulated in FF NSCLC tissues. The associations between these miRNAs and their clinicopathological features were also investigated. miR-363, -10a and -145 were associated with lymph node status (P=0.002, 0.005 and 0.007, respectively) and miR-650 and -145 were associated with differentiation (P=0.01 and 0.05, respectively). No associations were identified for the other miRNAs examined. In the FFPE NSCLC samples, miR-30e-5p correlated with the differentiation of the tissue (P=0.011). The present study indicates that these miRNAs may be appropriate candidates for molecular diagnostic and prognostic markers in NSCLC.