title: Prognostic value of circulating microRNA-21 in digestive system cancers: a meta-analysis.
abstract: Circulating microRNAs show aberrant expression in patients with cancer. The aim of this study was to investigate the prognostic value of circulating microRNA-21 (miR-21) in digestive system cancers.
  
  
  METHODS
  All the eligible studies were searched by Medline and EMBASE. The hazard ratios (HRs) for overall survival (OS), which compared the expression levels of circulating miR-21 in patients with digestive cancer was extracted and estimated. Pooled HRs and 95% confidence intervals (CI) were calculated. Then a meta-analysis was performed to clarify the prognostic value of the miR-21.
  
  
  RESULTS
  A total of seven studies involving 907 subjects were included. The results suggested that higher circulating miR-21 could predict worse OS outcome with the pooled HR of 2.19 (95% CI 1.01-4.75, P = 0.05) in digestive system cancers. Subgroup analysis by ethnicity indicated circulating miR-21 was associated with OS in patients with digestive cancer among Asians with the pooled HR of 2.90 (95% CI 1.30-6.45, P = 0.009). However, subgroup analysis by digestive system site revealed that there is no associated with OS in patients with colorectal cancer with the pooled HR of 1.34 (95% CI 0.45-4.00, P = 0.60).
  
  
  CONCLUSIONS
  The present findings suggest that circulating miR-21 is associated with poor survival in patients with digestive cancer and could be a prognostic biomarker for those patients.
authors: Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University Wenzhou 325000, Zhejiang, China.
authors: Ting-Ting
authors: TT
authors: Ye
authors: Department of Surgical Oncology, The First Affiliated Hospital of Wenzhou Medical University Wenzhou 325000, Zhejiang, China.
authors: Yin-Long
authors: YL
authors: Yang
authors: Department of Ultrasound, Zhejiang Provincial People's Hospital Hangzhou 310014, Zhejiang, China.
authors: Xin-Ying
authors: XY
authors: Liu
authors: Department of Surgical Oncology, The First Affiliated Hospital of Wenzhou Medical University Wenzhou 325000, Zhejiang, China.
authors: Qian-Qing
authors: QQ
authors: Ji
authors: Department of Surgical Oncology, The First Affiliated Hospital of Wenzhou Medical University Wenzhou 325000, Zhejiang, China.
authors: Yi-Fei
authors: YF
authors: Pan
authors: Department of Surgical Oncology, The First Affiliated Hospital of Wenzhou Medical University Wenzhou 325000, Zhejiang, China.
authors: You-Qun
authors: YQ
authors: Xiang
keywords: Digestive cancer; biomarker; circulating miR-21; meta-analysis; prognosis