Long noncoding RNA X-inactive specific transcript as a prognostic factor in cancer patients: A meta-analysis based on retrospective studies

BACKGROUND/AIMS: Emerging evidence showed the long noncoding RNA X-inactive specific transcript (lncRNA XIST) may play a crucial role in various cancers. However, its prognostic value in cancer patients remains controversial. Therefore, we performed an in-depth meta-analysis to investigate the potential clinical value of lncRNA XIST as a prognostic marker for cancer patients. METHODS: A comprehensive literature search was performed from PubMed, Embase and the Cochrane Central Search Library by January 2018. Pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence interval (95% Cl) were calculated to evaluate the prognosis as well as clinicopathological parameters of XIST, respectively. RESULTS: A total of 18 retrospective studies with 1351 cancer patients were included. Current meta-analysis revealed that elevated lncRNA XIST expression was associated with poor overall survival (OS) (HR = 2.14, 95% CI = 1.26–3.64; P = .005) and disease free survival (DFS) (HR = 4.52, 95% CI = 1.42–14.37; P = .011). The clinicopathological parameters analysis demonstrated that increased XIST expression was significantly associated with tumor size (OR = 2.93, 95% CI = 2.24–3.84; P < .001), clinical stage (OR = 2.73, 95% CI = 1.62–4.58; P < .001) and lymph node metastasis (OR = 2.44, 95% CI = 1.74–3.42; P < .001). In addition, subgroup analysis based on cancer type revealed that lncRNA XIST expression correlated with distant metastasis in digestive cancer (OR = 2.90, 95% CI = 1.80–4.68; P < .001). CONCLUSION: The current meta-analysis results indicated lncRNA XIST expression level could serve as a prognostic predictor and biomarker in multiple cancers.