MicroRNAs as ideal biomarkers for the diagnosis of lung cancer

Lung cancer (LC) is one of the most prevalent causes of cancer death with a high mortality rate worldwide. While various sets of microRNAs (miRNAs) have been found to be highly sensitive and specific biomarkers for the early diagnosis of LC (the first word of abstract), conflicting results on their diagnostic accuracy are still present in individual studies. Thus, we aimed to conduct a systematic review and meta-analysis of the published literature to comprehensively assess the diagnostic value of miRNAs for predicting LC. The sensitivity and specificity of each included study were used to plot the summary receiver operator characteristic (SROC) curve and to calculate the area under the SROC curve (AUC). All analyses were performed using the Stata 12.0 software. Twenty-six articles were involved in our meta-analysis, 18 of which focused on single miRNA assays and 15 on multiple miRNA assays. For single miRNA profiling, the pooled parameters calculated from all studies are as follows: sensitivity (SEN), 0.72; specificity (SPE), 0.74; positive likelihood ratio (PLR), 2.7; negative likelihood ratio (NLR), 0.39; and diagnostic odds ratio (DOR), 7. For multiple miRNA profiling, the pooled estimates for the overall studies are as follows: SEN, 0.81; SPE, 0.84; PLR, 4.9; NLR, 0.23; and DOR, 22, which are significantly better than the diagnostic performance of the single miRNA profiling. In addition, subgroup analyses based on sample types suggested that blood-based multiple miRNA assays were more accurate than non-blood-based studies. In conclusion, the current meta-analysis shows that multiple miRNA assays were more accurate in diagnosing LC than single miRNA assays. However, further large-scale investigations are urgently needed to confirm our results and verify the feasibility of routine clinical utilization.