MGMT and glioblastoma: Pre-treatment with 10 nM BTZ for 48 h followed by TMZ treatment significantly reduced the survival fraction of P3 and T98G GBM cells (unmethylated MGMT promoter) compared with TMZ monotherapy (P < 0.01 to P < 0.0001, Fig. 1m, n, respectively) and untreated controls (all P < 0.0001), but not BTZ alone (P > 0.05, Fig. 1m, n).