Long Noncoding RNA PVT1 as a Potent Predictor of Prognosis in Cancers: a Meta-Analysis.

Background: Plasmacytoma variant translocation 1 (PVT1), an oncogenic long noncoding RNA located in a recognized cancer-risk gene region-8q24, is significantly overexpressed in various cancers. Many studies have found that high expression of PVT1 was correlated with poor prognosis.
Methods: This meta-analysis was performed by searching electronic databases Pubmed, Web of Science, Chinese National Knowledge Infrastructure, WanFang, and ChongQing VIP for eligible papers on the prognostic impact and clinicopathological characteristics of PVT1 expression in cancer from inception to January 31, 2017. The hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals (CI) were computed to estimate the pooled effect of PVT1 on prognosis of cancers using Stata 12.0 version software.
Results: Thirteen studies were finally included in this review with a total of 1559 patients. The pooled result indicated that overexpressed PVT1 predicts a poorer prognosis of cancerous patients for overall survival (HR = 1.91, 95% CI: 1.61 - 2.26, p < 0.001) and disease-free survival (HR = 1.90, 95% CI: 1.46 - 2.48, p < 0.001) or recurrencefree survival (HR = 1.77, 95% CI: 1.24 - 2.52, p = 0.002) or progression-free survival (HR = 2.84, 95% CI: 1.67 - 4.82, p < 0.001). High expression of PVT1 was closely associated with tumor-node-metastasis (TNM) stage (III/IV vs. I/II: OR = 3.19, 95% CI: 2.43 - 4.18, p < 0.001), and the significant correlation between PVT1 expression and TNM stage is found in T classification (T3/4 vs. T1/2: OR = 6.48, 95% CI: 2.93 - 14.31, p < 0.001) and lymph node metastasis (present vs. absent: OR = 2.56, 95% CI:1.36 - 4.80, p = 0.003), but not in distant metastasis of patients with cancers (yes vs. no: OR = 2.50, 95% CI: 0.72 - 8.66, p = 0.15). Furthermore, the cancerous patients with high PVT1 expression had a worse histological differentiation than those with low PVT1 expression (undifferentiated/poorly vs. moderately/well: OR = 1.48, 95% CI: 1.02 - 2.14, p = 0.039).
Conclusions: PVT1 could serve as a potent predicator of prognosis in different types of cancers.