Prognostic and clinicopathological value of long noncoding RNA XIST in cancer

Background: It has been reported that lncRNA X-inactive specific transcript (XIST) is dysregulated in various cancers. We performed this meta-analysis to clarify its promising functions as a prognosis marker in malignant tumors. Methods: Eligible studies were recruited by a systematic search in OVID, Embase, Web of Science and PubMed databases. The hazard ratio (HR) and 95% confidence interval (CI) were calculated to explore the relationship between IncRNA XIST expression and patient's survival, which were extracted from the eligible studies. The odds ratio (OR) was calculated to assess the association between lncRNA XIST expression and pathological parameters using stata12.0 software. Results: Total 10 studies and 878 cancer patients were included in the study. The pooled HR suggested that high IncRNA XIST expression was significantly correlated with poor overall survival (OS) (HR = 2.61, 95% CI = 1.91-3.13, P < 0.0001) and short disease-free survival (DFS) (HR = 2.10, 95% CI = 1.10-3.11, P < 0.0001). It was demonstrated high level of lncRNA XIST was positively correlated with larger tumor size (OR = 1.89, 95% CI 1.34-2.06, P < 0.001), positive distant metastasis (OR = 1.75, 95% CI 1.03-2.96, P = 0.038) and high-grade cancer (OR = 1.64, 95% CI 1.22-2.21, P < 0.001). However, no correlation was observed between expression of IncRNA XIST and age (OR = 0.86, 95% CI 0.62-1.19, P = 0.352), gender (OR = 0.98, 95% CI 0.73-1.33, P = 0.769), lymphatic metastasis (OR = 1.41, 95% CI 0.97-2.04, P = 0.069) and differentiation (OR = 1.16, 95% CI 0.76-1.77, P = 0.497). Conclusions: This meta-analysis demonstrated that elevated lncRNA XIST expression predicts poor OS, poor DFS, larger tumor size, increased distant metastasis and advanced tumor stage, suggesting that high lncRNA XIST expression may serve as a novel biomarker for poor prognosis and metastasis in cancers.