The prognostic value of long noncoding RNA MEG3 expression in the survival of cancer patients: a meta-analysis

Long non-coding RNAs (lncRNAs) play an important role in carcinogenesis and cancer progression. lncRNA MEG3 is a tumor suppressor that is down-regulated in several cancers. However, its prognostic value in human malignancies remains controversial. We have therefore undertaken a meta-analysis to explore the relationship between cancer survival and the expression of long non-coding RNA MEG3. A systematic literature search identified 13 potentially eligible investigations comprising 1733 patients in nine different cancer types. In the pooled analysis, a low expression of MEG3 was associated with a low overall survival (OS) in cancer patients with a combined HR of 0.830 [hazard ratio (HR) =0.83; 95% CI: 0.70–0.98; P=0.0.03; random effect model]. However, sub-group analysis according to cancer type revealed that MEG3 expression was not associated with better OS in gastrointestinal cancer (HR = 0.58, 95% CI = 0.33 to 1.03, P = 0.06) and breast cancer patients (HR = 0.85, 95% CI: 0.12 to 5.88, P = 0.87). In conclusion, our results demonstrate that only in the pooled analysis, there was a significant relationship between MEG3 expression and cancer survival. Further investigation of other molecular biomarkers involved in tumorigenesis-related pathways is necessary.