Long non-coding RNA CASC2 in solid tumors: A meta-analysis.

BACKGROUND AND AIM: Recently, several studies have reported that the long non-coding RNA cancer susceptibility 2 (CASC2) is downregulated in human solid tumors. However, as the sample size in those studies was limited, the role of CASC2 in cancer remains unknown. Accordingly, we conducted this meta-analysis to explore the role of CASC2 in solid tumors.

METHODS: We systematically searched the PubMed, Medline, Cochrane Library, Web of Science, EMBASE, Ovid, Chinese CNKI, and Chinese WanFang databases. Pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence interval (CI) were used to evaluate the relation between CASC2 and the clinicopathological characteristics and prognosis of patients with cancer. Additionally, we also use The Cancer Genome Atlas (TCGA) dataset to analyze CASC2 expression.

RESULTS: A total of 15 studies with 1158 patients were included in this meta-analysis. The pooled results demonstrated that the expression of CASC2 was related to tumor size (large vs. small: OR = 0.40, 95% CI = [0.30, 0.52]), differentiation (low vs. high+ moderate: OR = 0.42, 95% CI = [0.29, 0.62]) and TNM stage (I + II vs. III + IV: OR = 2.74, 95% CI = [2.08, 3.60]), but not to age, gender and differentiation. High CASC2 expression indicated better overall survival (OS) (HR = 0.41, 95% CI = [0.32, 0.50]) and disease-free survival (DFS) (HR = 0.48, 95% CI = [0.26, 0.66]). Additionally, similar results were obtained through analysis of the TCGA data set. Moreover, it was determined that CASC2 could be an independent predictive factor for OS (HR = 0.38, 95% CI = [0.22, 0.54]) in patients with cancer.

CONCLUSION: This analysis revealed that low CASC2 expression was correlated with advanced clinicopathological characteristics of cancer tumors, and CASC2 may thus be a potential prognostic biomarker in human cancer. However, more studies are needed to further corroborate these findings.