Immunohistochemistry for O 6 -methylguanin-DNA methyltransferase in glioblastomas defined by WHO2016: Correlation with promoter methylation status and patients' progression-free survival with the cut-off value determined by ROC analysis.

•MGMT expression by IHC correlated with promoter methylation status by MSP in GBM.•MGMT expression was associated with clinical prognoses of GBM patient.•MGMT IHC could be used to estimate the efficacy of temozolomide and clinical outcome.