POTEH hypomethylation, a new epigenetic biomarker for glioma prognosis

POTE ankyrin domain family, member H (POTEH) belongs to POTE family, which expresses in many cancers. In this study, methylation status of POTEH promoter and its correlation with clinicopathological parameters were evaluated in glioma tissues and cells. Bisulfite sequencing PCR was carried out to investigate the promoter methylation status of POTEH in tumor of 96 glioma patients and glioma cells U251, SF767, and SF126. The effect of promoter hypomethylation on protein expression was evaluated by immunohistochemistry. POTEH was hypomethylated in 81.3% gliomas and none in normal brain tissues, and correlated significantly with its protein expression. But there was no remarkable relationship between sex, age, advanced tumor grade and POTEH hypomethylation. With the grade progressing, POTEH protein expression was enhanced. The correlation between POTEH hypomethylation, protein expression and overall survival was statistically significant. In POTEH hypomethylation group, patients with POTEH high expression had shorter overall survival than those with low expression. Hypomethylation of POTEH promoter in gliomas accounted for POTEH protein overexpression and poor outcome in a subset of patients. Detection of these epigenetic changes in tumors may provide information regarding prognosis.

Research highlights
► POTEH hypomethylated in glioma cells and tissues.
► Glioma patients harboring POTEH hypomethylation showed high level expression of POTEH protein.
► POTEH protein expression in tumors was significantly associated with tumor grade.
► Glioma patients with hypomethylated POTEH promoter or POTEH overexpression revealed shorter median overall survival.