With the exciting emergence of IDH inhibitors showing therapeutic efficacy in early clinical trials [144–146], this technology can be used to probe important mechanistic and translational questions related to treatment response and resistance, with the first of such studies providing an early glimpse into the biology of response and resistance in human IDH-mutant oligodendrogliomas after treatment with vorasidenib [194]. This evidence concerns the gene IDH1 and oligodendroglioma.