Combined inhibition of cysteine uptake or transsulfuration, and downregulation of GPX4 resulted in tumor regression in a NB mouse model.105 Buthionine sulfoximine (BSO), a selective inhibitor of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme in GSH synthesis, has been used in a clinical trial in patients with recurrent NB in combination with melphalan with promising results.106. The gene discussed is GPX4; the disease is neuroblastoma.