MGMT and glioblastoma: Dose intense TMZ treatment weakly attenuated expression of MGMT protein in partially unmethylated T98G,7,33 but not fully unmethylated P3 cells, consistent with previous findings where a TMZ dose intense regimen was deemed marginally effective.34,35 Several clinical studies have explored blocking MGMT to improve TMZ efficacy in treatment resistant GBM.36–39 Here, BTZ+TMZ 164 mg/m2 combination treatment extended survival of mice-bearing GBM with unmethylated MGMT promoter compared with TMZ 164 mg/m2 alone or a reduced dose BTZ+TMZ 82 mg/m2 combination treatment.