Long Non-Coding RNA TUG1 as a Potential Novel Biomarker for Predicting the Clinical Outcome of Cancer Patients: a Meta-Analysis.

<i>Background:</i> Emerging evidence suggests that long non-coding RNAs (lncRNAs) can be used as potential biomarkers for a wide range of cancers. Herein, the prognostic value of lncRNA taurine upregulated gene (TUG1) was analyzed using meta-analysis in different kinds of cancers. <i>Methods:</i> Databases including Cochrane Library, PubMed, and Chinese National Knowledge Infrastructure were searched for epidemiological studies up to March 2018. Hazard ratio (HR) and its 95% confidence interval (CI) were calculated to probe the relationship between TUG1 expression and overall survival of various cancer patients. The odds ratio (OR) was calculated to measure the strength of the association between TUG1 expression and gender, distant metastasis, vascular invasion, lymph node metastasis, and vascular invasion using Rev Man 5.3 and STATA12.0 software. <i>Results:</i> A total of 24 studies involving 2,117 cancer cases were enrolled. Our results demonstrated that a high expression of TUG1 was not associated with patient gender (odds ratio [OR] = 0.95, 95% confidence interval [CI] = 0.72 - 1.25, p = 0.71), but was a significant risk factor for distant metastasis (OR = 4.18, 95% CI = 1.89 - 9.27, p = 0.0004), vascular invasion (OR = 12.19, 95% CI = 2.71 - 54.89, p = 0.001) and lymph node metastasis (OR = 1.80, 95% CI = 1.16 - 2.80, p = 0.009). Furthermore, hazard ratio (HR) analysis suggested that TUG1 expression was not significantly correlated with overall survival (HR: 0.15, 95% CI: -0.21 to 0.51, p = 0.406), except for patients with bladder cancer (HR: 1.01, 95% CI: 0.25 - 1.78, p = 0.01). In the subgroup analysis, cancer type, sample size, and TUG1 expression levels affected the association between TUG1 expression and cancer prognosis. No evidence of publication bias was detected. <i>Conclusions:</i> Our meta-analysis revealed that a high expression of the lncRNA TUG1 was significantly associated with poor prognosis in patients with various cancers. Therefore, lncRNA TUG1 could be considered as a potential prognostic factor in different cancer types.