Immunoblotting showed that SLC3A2 levels were much higher in all cell lines than in normal T cells isolated from healthy volunteers, and nearly all cell lines exhibited low or undetectable ASS1 levels (Figure S2H, Supporting Information), indicating that arginine uptake by arginine transporters is a major arginine source in PTCL cell lines. This evidence concerns the gene ASS1 and mature T-cell and NK-cell non-Hodgkin lymphoma.