Clinical significance of blood-based miRNAs as biomarkers of non-small cell lung cancer.

Non-small-cell lung cancer (NSCLC) accounts for 85% of all cases of lung cancer. However, the predicted 5-year survival rate of patients with NSCLC is only 15.9%. microRNAs (miRNAs) are single-stranded, noncoding RNA molecules that are easily detectable in blood in a non-invasive manner, with features of stability, reproducibility and consistency in blood. Therefore, miRNAs derived from blood are able to have a significant impact on NSCLC diagnosis, metastasis and targeted therapies. Compared with the clinical protein markers carcinoembryonic antigen, cytokeratin fragment 21-1 and cancer antigen-125, blood-based miRNAs also display a higher diagnostic efficacy in NSCLC. Exosomal miRNAs are identified to be easily measured and have the potential to be used as diagnostic biomarkers in NSCLC, therefore providing an alternative method of biopsy profiling. The miRNA profile in exosomes is similar to the profile in primary tumor, meaning that this feature may be a powerful tool for NSCLC clinical diagnosis and targeted therapies. The focus of the present review was the clinical significance of blood-based exosomal miRNAs in diagnosis, prognosis, metastasis and targeted therapies of NSCLC.