MicroRNAs as novel biomarkers in the diagnosis of non-small cell lung cancer: a meta-analysis based on 20 studies

The detection of microRNAs (miRNAs), particularly those obtained from the bloodstream, is an emerging method for diagnosing human cancers, including non-small cell lung cancer (NSCLC). However, studies on the accuracy of miRNAs detection in diagnosing NSCLC have yield inconsistent conclusions, making it necessary to conduct a meta-analysis to systematically evaluate the diagnostic value of miRNAs in the diagnosis of NSCLC. The Medline, Embase, Chinese National Knowledge Infrastructure (CNKI), and Sinomed electronic databases were searched to identify all related articles evaluating the diagnostic value of miRNAs for NSCLC. A bivariate regression model was used to calculate the pooled diagnostic accuracy estimates. A total of 20 articles were included in this meta-analysis, involving 1,563 NSCLC patients and 1,060 healthy controls. Overall, our bivariate random effects meta-analysis yielded area under curve (AUC) of 0.85 (95 % CI: 0.82-0.88) with sensitivity of 76 % (95 CI: 72-80) and specificity of 80 % (95 % CI: 77-84) for the use of miRNAs in differentiating NSCLC patients from healthy controls. In addition, subgroup and meta-regression analyses revealed that a combination of multiple miRNAs (AUC, sensitivity, and specificity of 0.89, 81, and 84, respectively) had a higher diagnostic accuracy than single miRNA-based assays (AUC, sensitivity, and specificity of 0.81, 73, and 77 %, respectively). Furthermore, a comparison of miRNAs expression patterns between blood and sputum samples provides additional evidence that miRNAs obtained from blood (AUC, sensitivity, and specificity of 0.86, 78, and 80 %, respectively) are more credible diagnostic biomarkers than those from sputum (AUC, sensitivity, and specificity of 0.79, 66, and 79 %, respectively). In summary, the current meta-analysis suggests that the detection of miRNAs may be used in the future as an initial screening test for NSCLC, particularly, the detection of a combination of multiple miRNAs, which is a more comprehensive indicator than individual miRNAs.