Prognostic Value of MicroRNA-497 in Various Cancers: A Systematic Review and Meta-Analysis

BACKGROUND: Some studies showed that microRNA-497 (miR-497) might act as a prognostic biomarker of cancer. However, the conclusion was not consistent. The aim of this study was to investigate the prognostic role of miR-497 in various carcinomas. METHODS: We systematically searched the databases of PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Data to identify relevant studies. Two independent reviewers performed the data extraction and assessed the study quality. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) for overall survival (OS) and disease-free survival/relapse-free survival (DFS/RFS) were used to assess the associations between miR-497 expression and cancer prognosis. RESULTS: A total of 15 studies involving 1760 participants fulfilled the inclusion criteria. The lower level of miR-497 expression was significantly associated with shorter overall survival (HR = 2.19, 95% CI: 1.84-2.60). No significant association was found between miR-497 expression and DFS/RFS in various carcinomas (HR = 1.17, 95% CI: 0.53-2.57). Subgroup analyses by ethnicity and cancer type showed the consistent results. CONCLUSION: Our studies suggested that miR-497 might be a prognostic biomarker in cancers. However, further multicenter prospective clinical researches are needed to confirm the association between miR-497 expression and cancer prognosis.