Background and objectives: Bmi1 and EZH2 are involved in tumorigenesis of gliomas. However, clinicopathologic significance of their expression in gliomas is unknown; especially, the prognostic value of combined expression of Bmi1 and EZH2 has not been explored.
Methods: Bmi1 and EZH2 expression in human gliomas and nonneoplastic brain tissues was measured by immunohistochemistry.
Results: Both Bmi1 and EZH2 expressions in glioma tissues were significantly higher than those in corresponding nonneoplastic brain tissues (both P<0.001). Additionally, the upregulations of Bmi1 and EZH2 proteins were both significantly associated with advanced WHO grades (both P<0.001) and low KPS (P=0.008 and 0.01, respectively). Moreover, the overall survival of patients with high Bmi1 protein expression (P=0.006) or high EZH2 protein expression (P=0.01) was obviously lower than those with low expressions. More interestingly, glioma patients with combined overexpression of Bmi1 and EZH2 proteins had the shortest overall survival (P<0.001). Furthermore, multivariate analysis showed that Bmi1n expression (P=0.02), EZH2 expression (P=0.03), and combined expression of Bmi1 and EZH2 (P=0.008), were all independent prognostic factors for overall survival in glioma patients.
Conclusions: Our data suggest for the first time that the combination of Bmi1 and EZH2 overexpression may be a highly sensitive marker for the prognosis in glioma patients.
Keywords: Bmi1 polycomb ring finger oncogene; Clinicopathologic characteristics; Enhancer of zeste homolog 2; Glioma; Immunohistochemistry; Prognosis.
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