Tissue microRNA-21 expression predicted recurrence and poor survival in patients with colorectal cancer – a meta-analysis

OBJECTIVE: MicroRNA-21 (miR-21) has been shown to play an important role in cancer prognosis. We performed a meta-analysis to evaluate the prognostic effect of miR-21 from tissues and serum on survival of the patients with colorectal cancer (CRC). METHODS: Relevant studies were identified by searching PubMed, Embase, and Cochrane Library. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of total and subgroup analyses, for overall survival (OS) and disease-free survival (DFS), were calculated to investigate the association between miR-21 expression and CRC prognosis. RESULTS: Our analysis included eleven studies (3,669 subjects). In addition, four studies explored the association between miR-21 and DFS, and ten studies focused on the prognostic value of miR-21 for OS. Our results indicated that increased miR-21 expression of tissues predicted both poor DFS and OS in patients with CRC (DFS: HR =1.59, 95% CI =1.20–2.10; OS: HR =1.53, 95% CI =1.23–1.90). Consistent results were observed among colon cancer and quantitative real-time polymerase chain reaction subgroups. CONCLUSION: Meta-analysis indicated that miR-21 predicted recurrence and poor survival in patients with CRC. miR-21 may be more suitable to predict cancer prognosis in colon cancer patients.