Prognostic role of microRNA-21 in various carcinomas: a systematic review and meta-analysis


  • Systematic review and Meta-analysis

Yulan Zhao, MD, PhD, Institutes for Advanced Interdisciplinary Research, East China Normal University, North Zhongshan Road #3663, Shanghai City 200062, China. Tel.: 86 21 62237225; fax: 86 21 62237226; e-mail:


Eur J Clin Invest 2011; 41 (11): 1245–1253


Background  Recent studies have shown that microRNAs (miRNA) could play a potential role as diagnostic and prognostic biomarkers of cancers. The aim of this meta-analysis is to summarize the global predicting role of miR-21 for survival in patients with a variety of carcinomas.

Design  Eligible studies were identified and assessed for quality through multiple search strategies. Data were collected from studies comparing overall, relapse-free or cancer-specific survival (CSS) in patients with cancer having higher miR-21 expression with those having lower levels. Pooled hazard ratios (HRs) of miR-21 for survival were calculated.

Results  A total of 17 studies dealing with various carcinomas were included for this global meta-analysis. For overall survival (OS), the pooled hazard ratio (HR) of higher miR-21 expression in cancerous tissue was 1·69 (95% CI: 1·33–2·16, P < 0·001), which could significantly predict poorer survival in general carcinomas. For relapse-free or CSS, elevated miR-21 was also a significant predictor, with a pooled HR of 1·48 (95% CI: 1·03–2·11, P = 0·033). Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with worse OS in head and neck squamous cell carcinoma (HNSCC) (HR 1·46, 95% CI: 1·13–1·87, P = 0·004) and carcinomas in digestion system (HR 1·56, 95% CI: 1·08–2·26, P = 0·018).

Conclusions  Our findings suggest that miR-21 detection has a prognostic value in patients with cancer, especially in HNSCC and digestion system cancers.