Aberrant expression of UCA1 in gastric cancer and its clinical significance.

Long noncoding RNAs (lncRNAs) have been shown to regulate tumor biology and might be used for cancer diagnosis, prognosis and potential therapeutic targets. Although up-regulation of lncRNA UCA1 (urothelial carcinoma-associated 1) in several cancers has been found, its role in gastric cancer remains elusive. The aim of this study was to detect the expression of lncRNA UCA1 in gastric cancer and its clinical association. The expression of UCA1 was detected in 112 pairs of tumorous and adjacent normal tissues from patients with gastric cancer, as well as in four gastric cancer cell lines and a human normal gastric epithelium cell line using RT-qPCR. Results showed that UCA1 expression was remarkably increased in gastric cancer tissues and cell lines compared with that in the normal control. Clinicopathologic analysis revealed that high UCA1 expression correlated with worse differentiation, tumor size, invasion depth and TNM stage in gastric cancer. Kaplan-Meier analysis showed that increased UCA1 expression contributed to poor overall survival (p = 0.017) and disease-free survival (p = 0.024) of patients. A multivariate survival analysis also indicated that UCA1 could be an independent prognostic marker. The levels of UCA1 in gastric juice from gastric patients were significantly higher than those from normal subjects (p = 0.016). Moreover, validation analysis showed that UCA1 levels were robust in differentiating gastric cancer patients from control subjects [area under the curve (AUC) = 0.721; 95 % confidence interval (CI) = 0.655-0.788, p < 0.01]. These results suggested that UCA1 might serve as a promising biomarker for early detection and prognosis prediction of gastric cancer.