Downregulation of a long noncoding RNA-ncRuPAR contributes to tumor inhibition in colorectal cancer

In recent years, the role of long noncoding RNAs (lncRNAs) in cancer is increasingly focused. ncRuPAR is a newly detected lncRNA; in previous study, we found out that ncRuPAR could inhibit tumor progression by downregulating protease-activated receptor-1 (PAR-1), but its role in colorectal cancer (CRC) is never elucidated. Here, we conducted a self-control study which includes 105 CRC samples. By quantitative real time PCR (qRT-PCR) and immunohistochemical staining, we detected the expression of ncRuPAR and PAR-1 as well as their correlation; we further associated these data with the clinicopathologic parameters. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of ncRuPAR and PAR-1, respectively. Our results indicated that the expression of ncRuPAR was significantly downregulated in CRC compared with paired adjacent nontumor tissues, but the level of PAR-1 mRNA in cancerous tissues was significantly higher than in adjacent normal areas. The expression of ncRuPAR was significantly correlated with lymph node metastasis, distant metastasis, Duck's stage, differentiation, and TNM stage and was potentially negatively associated with the mRNA levels and EI scores of PAR-1. The area under the ROC curve of ncRuPAR was 0.81 (95 % confidence interval (CI): 0.75-0.87); at a cutoff value of 8.34, the ncRuPAR measurement had a sensitivity of 97.14 %, a specificity of 65.87 %, and an accuracy of 82.86 % to predict CRC.