MGMT and glioblastoma: The efficacy of treatment also showed strong correlation with certain biomarkers, for example, patients with methylated O6-methylguanine methyltransferase (MGMT) promoter often benefit from temozolomide while patients with unmethylated MGMT do not (5), although the heterogeneity of glioblastoma and variability in MGMT expression across tumor regions complicates the correlation between MGMT expression and treatment response (6, 7).