Prognostic value of hypoxia-responsive long non-coding RNAs in gastric cancer: a meta-analysis

Background: Considerable evidence has shown that the hypoxic tumor microenvironment is closely associated with gastric cancer (GC) progression and prognosis. However, many of these studies included very few patients. Therefore, to improve the statistical relevance, this systematic review and meta-analysis was conducted to determine a scientific conclusion. This study examined the impact of hypoxia-responsive long non-coding RNAs (HRLs) on overall survival (OS) in gastric cancer. Methods: This study searched relevant published studies from Pubmed and Embase databases (up to December 2017). Standard meta-analysis methods were used to estimate the prognostic role of HRLs in patients with GC. Pooled hazard ratios (HRs), odds radio (OR) and their corresponding 95% confidence intervals (CIs) were calculated. Results: A total of 15 studies with 1,505 patients were identified and 5 long non-coding RNAs (lncRNAs (HOTAIR, H19, UCA1, GAPLINC, and MALAT1) were assessed in this meta-analysis. Elevated HOTAIR was predictive of poorer OS in GC (HR: 1.55; 95% CI: 1.21-1.88), as was high H19 and UCA1. Expression of GAPLINC and MALAT1 was not related to patient outcomes. Regarding clinicopathology, increased H19 was associated with positive lymph node metastasis (OR = 1.68, 95% CI: 1.02-2.76), deeper tumor invasion (OR = 3.53, 95% CI: 1.37-9.10), and advanced TNM stages (OR = 2.17, 95% CI: 1.33-3.56). Conclusion: Specific hypoxia-responsive lncRNAs may serve as novel prognostic markers in GC.