Indeed, we also observed that the toxicity of CB-839 in ENO1-deleted cells is significantly attenuated in physiological PlasmaxTM medium compared to DMEM medium (Supplemental Figure S14), which implies that in vivo tumor microenvironment may not be conducive to glutamine addiction, at least for ENO1-deleted gliomas. The gene discussed is ENO1; the disease is central nervous system cancer.