Previous studies have demonstrated that the suppression of the urea cycle induces reliance on exogenous arginine sources and is associated with poor survival in various cancers.[19, 67, 68] We also noted the silencing of the key arginine synthesis enzyme ASS1 in patients with PTCL, indicating that PTCL exhibits arginine auxotrophy. This evidence concerns the gene ASS1 and mature T-cell and NK-cell non-Hodgkin lymphoma.