Expression of circRNA circ_0026344 in gastric cancer and its clinical significance.

Emerging evidence indicates that circular RNAs (circRNAs) are a novel class of biomarkers and therapeutic targets in malignancies. Circ_0026344 has been reported to be downregulated in colorectal cancer, and associated with prognosis. However, little is currently known regarding its expression and clinical significance in gastric cancer. In this study, we evaluated the expression level of circ_0026344 in two previous circRNAs chips (GSE78092 and GSE89143) for gastric cancer. 93 pairs of gastric cancer and adjacent non-tumour tissues were collected, and qRT-PCR was applied to determine circ_0026344 expression. The level of circ_0026344 in gastric cancer cells (MKN45 and AGS) and a normal gastric epithelial cell line (GES-1) was also analyzed. Chi-square test was used to identify the association between circ_0026344 level and clinicopathologic factors. Kaplan-Meier method with log-rank test was applied to compare survival curves. Cox regression analyses were used to assess the prognostic value of circ_0026344. In GSE24549 and GSE24550 datasets, downregulation of circ_0026344 was observed. In 93 cases of gastric cancer, circ_0026344 in cancer tissues was significantly decreased compared to adjacent non-cancerous tissues, and its level was markedly associated with tumour size, lymph node metastasis, TNM stage, and invasive depth. Furthermore, patients with lower expression of circ_0026344 showed significantly worse overall survival than those with higher expression. Additional, circ_0026344 expression was an independent predictor for overall survival. Summarily, our study highlights that downregulation of circ_0026344 is associated with tumour malignant behavior and it is a potential biomarker for gastric cancer prognosis.