The prognostic value of abnormally expressed lncRNAs in colorectal cancer: A meta-analysis

BACKGROUND: Colorectal cancer (CRC) is the third most prevalent cancer type and the third leading cause of cancer-related deaths worldwide, it is urgently needed to discover a new marker for the progress of CRC. Many long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in CRC, and may be feasible as effective biomarkers and prognostic factors. The aim of this study was to identify the prognostic value of various lncRNAs in CRC. METHODS: Pubmed, Web of Science, Embase and Cochrane Library were searched for potentially related studies. A total of 34 eligible studies including 30 on overall survival (OS), 7 on disease-free survival (DFS), 1 on relapse-free survival (RFS), 2 on disease-specific survival (DSS) and 29 on clinicopathological features were qualified from the databases. RESULTS: The results showed that the expression levels of lncRNAs were significantly associated with poor OS (hazard ratio (HR) = 2.08, 95% confidence interval (CI) = 1.68–2.57, P<0.001, I(2) = 70%), DFS (HR = 1.79, 95% CI = 1.54–2.08, P<0.001, I(2) = 6%) and DSS (HR = 0.11, 95% CI = 0.02–0.54, P = 0.007, I(2) = 14%). Subgroup analysis further showed that lncRNA transcription level was significantly associated with tumor differentiation (odds ratio (OR) = 0.51, 95% CI = 0.34–0.77, P = 0.001), lymph node metastasis (OR = 1.63, 95% CI = 1.23–2.17, P = 0.0007), distant metastasis (OR = 2.06, 95% CI = 1.29–3.30, P = 0.002), TNM stage (OR = 0.44, 95% CI = 0.32–0.62, P<0.001), tumor invasion depth (OR = 0.48, 95% CI = 0.39–0.60, P<0.001). CONCLUSIONS: The meta-analysis demonstrated that abnormal lncRNA transcription level may serve as a promising indicator for prognostic of patients with CRC.