While glutathione accumulation has been already reported in NSCLC37, we further demonstrate that not only GSH but also its precursors, γ-glutamyl-cysteine (GluCys), cysteine and homocysteine (HCys) are increased in tumor tissue, as well as the degradation product of glutathione, cysteinyl-glycine (CysGly; Fig. 3C), in line with the observed greater abundance of glutathione hydrolase (GGT) in cancer tissue (Fig. 3A; Supplementary Data 2). The gene discussed is GGT1; the disease is cancer.