RRM2 (ribonucleotide Reductase Regulatory TP53 Inducible Subunit M2B) has been identified as a tumor biomarker associated with ferroptosis in liver cancer (Yang et al., 2020a), and Tang et al. (2021) used sustained GSH production to show that RRM2 has an anti-ferroptotic effect. Here, RRM2 is linked to liver cancer.