Long non-coding RNA XIST as a potential prognostic biomarker in human cancers: a meta-analysis

Growing studies have confirmed that long non-coding RNAs (lncRNAs) involve in the occurrence and development of various cancers. XIST, as a lncRNA, was dysregulated in different cancers. This meta-analysis was performed to evaluate the prognostic potential of XIST in malignant tumors. Eight databases of PubMed, Web of Science, Embase, Cochrane library, CNKI, VIP, SinoMed and Wang Fang were comprehensively searched from their initiation date to August 15, 2017. A total of nine studies with 853 cancer patients met the including criteria were finally included in this meta-analysis after independently screening the literatures by two researchers. Any discrepancies were resolved by a consensus. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) for the primary endpoints were extracted and pooled for meta-analysis. Our results showed that expression level of XIST was markedly associated with overall survival (function as oncogene, HR = 0.53, 95% CI: 0.42-0.68, p < 0.00001; function as tumor suppressor, HR = 2.25, 95% CI: 1.15-4.37, p = 0.02), disease free survival (DFS)(HR = 0.45; 95% CI: 0.31-0.67, p < 0.0001), tumor type (digestive system carcinoma, HR = 0.50; 95% CI: 0.37-0.69, p < 0.00001; non-digestive system carcinoma, HR = 0.58; 95% CI: 0.39-0.87, p = 0.008), lymph node metastasis (OR = 0.32, 95% CI: 0.20-0.52, p < 0.00001), distant metastasis (OR = 0.36, 95% CI: 0.22-0.60, p < 0.0001) and tumor stage (OR = 0.43, 95% CI: 0.31-0.60, p < 0.00001). In conclusion, the pooled results in our current work suggest that XIST is an important prognostic biomarker in cancer patients.