Restoration of DKK1 expression by a demethylating agent 5-azacytidine in T98 GBM cells enhances their susceptibility to camptothecin- and etoposide-induced apoptosis (Foltz et al., 2010), suggesting that treatment of GBM cells with inhibitors of promoter methylation for tumor suppressors facilitates drug efficacy. The gene discussed is DKK1; the disease is neoplasm.