Long noncoding RNA CCAT2 as a novel biomaker of metastasis and prognosis in human cancer: a meta-analysis

Colon cancer-associated transcript2 (CCAT2), a long noncoding RNA (LncRNA), has been found to function as an oncogene in various cancers. However, the clinical value of CCAT2 in cancers remains unclear. Therefore, we performed this meta-analysis to investigate the association between CCAT2 level and metastasis & prognosis in malignant tumors. The meta analysis was performed by using a systematic search in PubMed, Web of Science, and Cochrane Library from inception to NOV 17, 2016. According to the inclusion and exclusion criteria,9 studies with 1084 patients were included in the meta-analysis.The result showed that overexpression of CCAT2 is positively correlated with lymph node metastasis (Odds ratio,OR=3.57, 95 % confidence interval(CI): 1.79-7.13, p<0.001) in a random-effects model (I(2)=71%, p=0.008) and distant metastasis(OR=7.68, 95 % CI: 3. 29-17.96, p<0.001) in a random-effects model (I(2)=41.9%, p=0.16).Likewise,we also found that high CCAT2 expression could predict unfavourable overall survival with pooled hazard ratio (HR) of 2.23 (95 % CI 1.68-2.96, p<0.00001) by a random-effects model (I(2)=37.5%, p=0.143) and poor metastasis-free survival in cancer patients (HR= 2.08, 95%CI:1.37-3.18 p=0.001) by a fixed-effects model (I(2)=0.0%, p=0.807). In conclusion,CCAT2 might be served as a novel molecular marker for predicting metastasis and prognosis in various human-cancers.