Comparison of WT IDH1/2 and mutIDH1/2 cells has revealed a more than 100-fold change (FC) in R-2-HG levels for chondrosarcoma cells (HT1080),95 glioma cells (LN18),113 glioma PDX mouse models,188 and glioma PTBs.7 The gene discussed is IDH1; the disease is chondrosarcoma.