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

Dailian Wang,Zhicong Chen,Anbang He,Yuchen Liu,Weiren Huang,Haidan Xu

doi:10.18632/oncotarget.18161

Abstract

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 (I2=71%, p=0.008) and distant metastasis(OR=7.68, 95 % CI: 3. 29-17.96, p<0.001) in a random-effects model (I2=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 (I2=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 (I2=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.

Highlights

Cancer incidence and moratlity are increasing each year, making cancer a major public health problem and the leading cause of death worldwide
Because of the existence of heterogeneity (I2=71%, p=0.008),we performed a sensitivity analysis to clarify the possible source of heterogeneity.After excluding the Zhang study[18],the heterogeneity obviously declined(I2 =49.9%, P =0.112) and the results did not change (OR=4.59, 95 % confidence intervals (CI):2.36-8.93, P
Long noncoding RNAs (LncRNA) CCAT2 which has been detected to be overexpressed in many malignancies may act as a novel oncogene [7, 8]

Summary

INTRODUCTION

Cancer incidence and moratlity are increasing each year, making cancer a major public health problem and the leading cause of death worldwide. Colon cancer-associated transcript 2(CCAT2), a 1752-bp lncRNA transcribed from m8q24 genomic region, was first discovered by Ling et al in 2013 [7] They found that genomic locus of CCAT2 is highly conserved and harbors the SNP rs6983267.It was highly expressed in microsatellite-stable colorectal cancer and promotes tumor growth, metastasis, and chromosomal instability. Wang et al observed that high lncRNA CCAT2 expression was correlated with lymph node metastasis and distance metastasis (DM)in gastric cancer [11].Wu et al found that knockdown of CCAT2 can inhibit cervical cancer cell proliferation and promote cervical cancer cells apoptosis [16] These studies suggest that CCAT2 gene may act as a novel oncogene in these tumors,regulating celluar growth,migration and apoptosis. We performed this meta-analysis to investigate the lymph node metastasis, distant metastasis and clinical prognostic role of overexpression CCAT2 in human cancers

RESULT

DISCUSSION

Findings

Literature search