Background: The aim of this study was to elucidate the clinicopathological significance of enhancer of zeste homolog 2 (EZH2) expression in gliomas, including its incidence and prognostic role. In addition, we investigated the concordance between immunohistochemistry and polymerase chain reaction for determining the presence or absence of EZH2 in these tumors.
Methods: The current meta-analysis included 1,049 gliomas with various WHO tumor grades from 12 eligible studies, which were analyzed for positivity of EZH2 and correlation between EZH2 expression and prognosis. Subgroup analyses were performed based on detection methods and WHO tumor grades.
Results: We found the estimated positive rate of EZH2 in gliomas to be 0.663 (95% confidence interval [95% CI], 0.549-0.761). There was no difference between immunohistochemistry and polymerase chain reaction in determination of EZH2 positivity (0.706, 95% CI, 0.539-0.831 vs. 0.673, 95% CI, 0.472-0.825). The positive rate of EZH2 increased by increasing WHO tumor grade. EZH2 expression was significantly correlated with worse overall and progression-free survival (hazard ratio [HR] = 2.436, 95% CI, 1.350-4.393, and HR = 4.071, 95% CI, 1.325-12.508, respectively). The overall concordance rate between immunohistochemistry and polymerase chain reaction was 0.885 (95% CI, 0.300-0.993).
Conclusions: EZH2 positivity was significantly correlated with WHO tumor grade and worse prognosis in gliomas.
Keywords: Concordance analysis; EZH2; Glioma; Meta-analysis; Prognosis.