High EMP3 expression might independently predict poor overall survival in glioblastoma and its expression is related to DNA methylation.

Abstract

In this study, we analyzed the prognostic value of epithelial membrane protein 3 (EMP3) in terms of overall survival (OS) in glioblastoma multiforme (GBM) and the association between its expression and DNA methylation.Bioinformatic analysis was performed by using data from the Cancer Genome Atlas (TCGA) database.EMP3 expression was markedly higher in GBM tissues than in normal brain tissues. High EMP3 expression was associated with significantly worse OS in patients with GBM. Univariate and multivariate analysis showed that EMP3 expression was an independent prognostic factor of poor OS no matter converting its expression into categorical variables (Hazard Ratio [HR] = 1.359, 95%CI: 1.118–1.652, P = .002) or setting it as a continuous variable (HR = 1.178, 95%CI: 1.101–1.260, P < .001). Among different subtypes of GBM, proneural subtype had the lowest EMP3 expression. The lowest EMP3 expression was observed in cluster 5 DNA methylation, which all belong to G-CIMP phenotype. Regression analysis confirmed a moderate negative correlation between EMP3 expression and its DNA methylation (Pearson's r = −0.61).Based on these findings, we infer that high EMP3 expression might be an independent indicator of unfavorable OS in GBM. EMP3 expression might be repressed by DNA methylation.