Prognostic value of long non-coding RNA HOTAIR in various cancers

Long non-coding RNA has been involved in cancer progression, and high HOX transcript antisense intergenic RNA (HOTAIR) is thought to be a poor prognostic indicator in tumorigenesis of multiple types of cancer. Hence, the present study further reveals its prognostic value in tumor malignancy. A systematic review of PubMed and Web of Science was carried out to select literatures relevant to the correlation between HOTAIR expression levels and clinical outcome of various tumors. Overall survival (OS), metastasis-free survival (MFS), recurrence-free survival (RFS), and disease-free survival (DFS) were subsequently analyzed. Data from studies directly reporting a hazard ratio (HR) and the corresponding 95% confidence interval (CI) or a P value as well as survival curves were pooled in the current meta-analysis. A total of 2255 patients from 19 literatures almost published in 2011 or later were included in the analysis. The results suggest that HOTAIR was highly associated with HR for OS of 2.33 (95%CI = 1.77-3.09, Pheterogeneity = 0.016). Stratified analyses indicate that elevated levels of HOTAIR appears to be a powerful prognostic biomarker for patients with colorectal cancer (HR = 3.02, 95CI% = 1.84-4.95, Pheterogeneity = 0.699) and esophageal squamous cell carcinomas (HR = 2.24, 95CI% = 1.67-3.01, Pheterogeneity = 0.711), a similar effect was also observed in analysis method and specimen, except for ethnicity. In addition, Hazard ratios for up-regulation of HOTAIR for MFS, RFS, and DFS were 2.32 (P<0.001), 1.98 (P = 0.369), and 3.29 (P = 0.001), respectively. In summary, the high level of HOTAIR is intimately associated with an adverse OS in numerous cancers, suggesting that HOTAIR may act as a potential biomarker for the development of malignancies.