Whether we examined fractional enrichments normalized to glutamine (m+5) levels in the tumor cells (SI Appendix, Fig. S3 E and F) or nonnormalized fractional enrichments (SI Appendix, Fig. S3 G and H), we did not observe significant differences in the contribution of labeled glutamine to TCA cycle intermediates in the G6PD mutant as compared to control melanomas. The gene discussed is G6PD; the disease is neoplasm.