IDH3A and glioblastoma: Early data from several metabolomic studies in small cohorts of patients with GBM have yielded promising results.9,10 GBM is a heterotrophic tumor but is also known to have highly heterogeneous lipid metabolism11 and favors heterotrophy.12,13 Prior studies have compared metabolomic profiles of GBM tissue with lower grade gliomas, examining isocitrate dehydrogenase wild type versus mutant variants.