In cisplatin-resistant lung cancer cells, four glutathione-metabolizing enzymes, aminopeptidase N (CD13), glutathione peroxidase 4 (GPX4), 5-oxoprolinase (OPLAH) and ribonucleotide reductase regulatory TP53 inducible subunit M2B (RRM2B) were up-regulated, suggesting that glutathione metabolism plays a key role in acquiring cisplatin resistance [13]. The gene discussed is ANPEP; the disease is lung cancer.