IDH1 and glioblastoma: Using base editing we generated IDH-mutant cells (IDH1R132H/WT) by introducing a single-base substitution (guanine to adenosine) in IDH-wild-type LN18 human glioblastoma cells to evaluate whether the IDH R132H mutation negatively regulates LOC expression via hypermethylation of its promoter chromatin (Fig. 2d).