A recent report showed that in 2D cancer cultures, glutamine is transformed into α-ketoglutarate via glutamate and then oxidized along the Krebs cycle; however, in 3D cultures, glutamine-derived α-ketoglutarate was produced in the cytosol and transformed into isocitrate/citrate via IDH1-dependent reductive carboxylation39,40. Here, IDH1 is linked to cancer.