Long noncoding RNA CCAT2 can predict metastasis and poor prognosis: A meta-analysis.

Background: It has been reported that Colon cancer-associated transcript 2 (CCAT2) is dysregulated in various cancers. We performed this meta-analysis to clarify its promising functions as a prognosis marker in malignant tumors.

Methods: Electronic databases, including PubMed, Medline, OVID, Cochrane Library, and Web of Science, were searched from inception to October 20, 2016. The hazard ratio (HR) and 95% confidence interval (CI) were calculated to explore the relationship between CCAT2 expression and survival, which were extracted from the eligible studies. The odds ratio (OR) was calculated to assess the association between CCAT2 expression and pathological parameters using RevMan5.3 software.

Results: Six original studies were included in this meta-analysis including 725 cancer patients. The pooled HR suggested that high CCAT2 expression was significantly correlated with overall survival (OS) (HR=2.30, 95% CI: 1.62-3.25, p<0.00001) in cancer patients. Subgroup analysis revealed a significant association between CCAT2 and OS in urogenital system (HR=1.70, 95% CI: 1.27-2.26, p<0.003) and non-urogenital system cancer patients (HR=3.18, 95% CI: 2.09-4.83, p<0.0001). A significant association was observed between high CCAT2 expression and poor progression-free survival (PFS) in cancer patients (pooled HR=2.76, 95% CI: 1.74-4.37). CCAT2 expression was significantly related to lymph node metastasis (LNM) (OR=4.33, 95% CI 2.03-9.22), distant metastasis (DM) (OR=11.66, 95% CI: 5.36-25.37) and tumor stage (OR=2.58, 95% CI 1.86-3.57).

Conclusions: This meta-analysis demonstrated that high CCAT2 expression significantly predicts poor OS, poor PFS, LNM, DM and tumor stage, suggesting that high CCAT2 expression may serve as a novel biomarker for poor prognosis and metastasis in cancers.