Analysis of MGMT activity by measuring the ability of cellular extracts to remove methyl adducts from the O6 position of guanine in a methylated DNA substrate (Figure 1C) revealed a direct correlation between MGMT activity and protein expression in GCS and GBM cell lines (Spearman’s correlation = 0.87, P < 0.0001, n = 12). The gene discussed is MGMT; the disease is glioblastoma.