IDH1 and central nervous system cancer: To demonstrate the utility of IC-MS in a discovery-driven untargeted context, we compared wild-type IDH1 LN18 glioblastoma cells with those expressing the R132H mutant form of IDH1. Somatic mutations in genes encoding IDH1 and 2 are found in over 80% of grade 2 and 3 glioma, some glioblastomas and over 13 other types of cancer16–18.