RRM2 and neoplasm: As supposed, most GSH metabolism related enzymes like GGT5, GPX1, GPX2, GPX4, GSR, GSS, GSTA1, GSTA2, GSTO1, IDH, IDH2, RRM1, RRM2 and SRM were highly expressed in THCA samples, while expression of GCLC, GCLM, GPX3, OPLAH, PGD and SMS were decreased in tumor tissues (Figures 1A, B).