Glutathione peroxidase 4 (GPX4), the enzyme that has a central role in preventing ferroptosis induction by oxidative damage, was found to be downregulated in human MS brain specimens ex vivo and in experimental autoimmune encephalitis (EAE), along with other two negative modulators of ferroptosis, cystine–glutamate antiporter (xCT) and γ-glutamylcysteine ligase (GCLC) [7]. The gene discussed is GPX4; the disease is myeloid sarcoma.