GLS and cancer: We selected the potent small‐molecule glutaminase inhibitor CB‐839, which is currently undergoing a phase I clinical trials for solid tumors (NCT02071862, NCT02771626; Choi & Park, 2018) to suppress glutaminase activity because it is rate‐limiting in the uptake and utilization of glutamine in cancer cells (Altman et al, 2016; Davidson et al, 2016).