The accuracy of circulating micro RNA ‐21 in the diagnosis of colorectal cancer: a systematic review and meta‐analysis

Aim The accuracy and clinical value of circulating micro RNA ‐21 (miR‐21) were assessed as a novel diagnostic biomarker of colorectal cancer ( CRC ). Method Medline/PubMed, EMBASE , the Cochrane Library databases and grey literature (Google scholar; British Library) were searched up to 29 September 2014 for eligible studies of the association between blood‐based miR‐21 and a diagnosis of CRC . Quality Assessment of Diagnostic Accuracy Studies ( QUADAS ) was employed to assess the quality of the included studies by two investigators. Stata12.0 and Meta‐DiSc1.4 software were applied to test the heterogeneity using Cochran's Q test and I 2 statistics and to perform the meta‐analysis. Results Seven studies with 676 CRC patients and 417 controls were included in the meta‐analysis. All were of high quality ( QUADAS scores 12 or 13). For miR‐21, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio to predict CRC were 75% [95% confidence interval ( CI ) 63–83%], 84% (95% CI 79–87%), 4.61 (95% CI 3.38–6.29), 0.30 (95% CI 0.20–0.46) and 16.89 (95% CI 7.56–37.73) after using a random‐effects model analysis. The area under the summary receiver operating characteristic curve was 0.86 (95% CI 0.83–0.89). Conclusion The results suggest that circulating miR‐21 is a biomarker with moderate sensitivity and specificity for CRC .