Reitman et al. also found reduced levels of phosphocholine (PC) and increased levels of glycerophosphocholine (GPC) in mutant IDH1 glioma cells relative to wild-type cells [22] and these results were in line with a subsequent study by Esmaeili et al. that showed increased GPC levels in mutant IDH1 gliomas relative to wild-type tumors [24]. Here, IDH1 is linked to central nervous system cancer.