Jose et al. [5] investigated The Cancer Genome Atlas (TCGA) data and found that the level of pyruvate carboxylase was higher in human gliomas containing the IDH1 mutation than in those with wild-type IDH1. The fractional flux, which depends on the activity of pyruvate carboxylase, is therefore increased in cells with the IDH1 mutation. Here, IDH1 is linked to central nervous system cancer.