Prognostic Significance and Diagnostic Value of Overexpressed lncRNA PVT1 in Colorectal Cancer

Background: The aim of this study is to investigate the expression of lncRNA PVT1 in CRC tissue compared to adjacent normal tissues, and reveal the association between lncRNA PVT1 expression level and the clinicopathological characteristics of patients with CRC. Methods: We detected the lncRNA PVT1 relative expression of cancerous tissues in 130 patients with CRC by using real-time quantitative polymerase chain reaction. At the same time, we collected the clinicopathological and prognostic information. Results: IncRNA PVT1 was overexpressed in CRC tissues compared to paired-adjacent normal tissues and the high expression rate was 72.31%. High expression of lncRNA PVT1 predicts a later tumor stage (p = 0.001), poorer tissue differentiation (p = 0.019), and higher plasma CEA level (p = 0.043). Additionally, the lncRNA PVT1 expression was closely related to lymph node metastasis (N1/N2 vs. N0) and distant metastasis (M1 vs. M0) in CRC patients (p = 0.002; p = 0.003), but not to tumor T classification (p = 0.314). The result of prognostic analysis indicated that the 1-year and 3-year DFS of the lncRNA PVT1 low and high expression patients were 93.8% and 81.1%, 69.3% and 44.7%, respectively. The median DFS was 44 months in low expression group and 26 months in high expression group, with statistical significance (p = 0.021). COX multivariate analysis showed that TNM staging (III/IV vs. I/II: HR = 6.342, 95% CI: 2.994 - 13.433, p < 0.001) and the lncRNA PVT1 expression (high expression vs. low expression: HR = 3.744, 95% CI: 1.493 - 9.392, p = 0.005) was closely related to DFS in CRC patients. As with tumor TNM staging, lncRNA PVT1 expression was also an independent prognostic predictor of DFS. The proportion of lncRNA PVT1 high expression (fold change >= 1.725) was higher than that of elevated CEA (> 5 ng/mL) in different CRC stages, especially, there was a significant difference in stage I patients (X-2 = 41.717, p < 0.0001). Conclusions: The lncRNA PVT1 was over-expressed in CRC tissues, which indicated a poor prognosis. The lncRNA PVT1 expression is far higher than the plasma CEA level in the early stage patients, which has the potential diagnostic value for early stage CRC.