Exosomal miRNAs as Biomarkers of Cancer: a Meta-Analysis

BACKGROUND: Tumor-derived exosomal miRNAs secreted by cancer cells play significant roles in the pathological processes of cancer, but no systematic meta-analysis has focused on the diagnostic efficiency of exosomal miRNAs. This meta-analysis assessed the diagnostic value of circulating exosomal miRNA in cancer. METHODS: Studies evaluating the diagnostic value of exosomal miRNA were identified in EMBASE, PubMed, Cochrane Library, and Web of Science up to August 1, 2018. The quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies 2, and STATA 14.0 was used for the analyses. The true positive (TP), false positive (FP), true negative (TN), and false negative (FN) rates were extracted from each study to obtain the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and their 95% confidence intervals (CIs). RESULTS: The meta-analysis included 16 studies with 1,591 patients. Five studies reported sensitivity values, and the pooled sensitivity was 0.86 (95% CI = 0.80 - 0.90, while 29 studies reported specificity values, and the pooled specificity was 0.89 (95% CI = 0.83 - 0.93). The pooled PLR was 7.8 (95% CI = 4.9 - 12.4), the pooled NLR was 0.16 (95% CI = 0.11 - 0.24), the pooled DOR was 48 (95% CI = 23 - 101), and the AUC was 0.94 (0.91 - 0.96). CONCLUSIONS: Our meta-analysis indicated that body fluid exosomal miRNAs are highly accurate for distinguishing patients from healthy individuals, and exosomal miRNAs have superior diagnostic value in plasma, prostate cancer patients, and non-Asian individuals.