title: Diagnostic value of circulating miR-21 for colorectal cancer: a meta-analysis.
abstract: BACKGROUND
  MicroRNA-21 (miR-21) is highly expressed in the plasma of colorectal cancer (CRC) patients. Thus, miR-21 may be a useful novel diagnostic biomarker for CRC. This meta-analysis aims to verify the diagnostic value of circulating miR-21 in CRC patients.
  
  
  METHODS
  A literature search was conducted for publications that evaluated the diagnostic value of miR-21 for CRC. The quality of each study was scored with the Quality Assessment of Diagnostic Accuracy Studies. The bivariate meta-analysis model was employed to summarize the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Receiver operating characteristic curves were used to check the overall test performance.
  
  
  RESULTS
  Five publications with six studies involving 579 patients and 266 controls were included in this meta-analysis. The pooled sensitivity was 77.4% [95% confidence interval (CI): 67.2%-85.1%], specificity was 84.6% (95% CI: 79.7%-88.5%), PLR was 5.02 (95% CI: 3.73-6.75), NLR was 0.27 (95% CI: 0.18-0.40), and DOR was 18.77 (95% CI: 10.41-33.83). The area under the summary ROC curve was 0.86. In addition, the results became prominent in the CRC group when a study that explored the advanced adenoma was excluded.
  
  
  CONCLUSIONS
  Circulating miR-21 may be a suitable diagnostic biomarker for CRC with moderate sensitivity and specificity. Further studies should evaluate the diagnostic value of miR-21 for CRC in the future.
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Liuqun
authors.initials: L
authors.lastname: Shan
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Ji
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Gongming
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xia
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Delin
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Changde
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Benlei
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Ding
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood* / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs
keywords: circulating; colorectal cancer; diagnosis; miR-21