Up-regulation of TBX21 or GATA3 and their target genes (EOMES, CXCR3, IL2RB, CCL3, IFNY, and CCR4, IL18RA, CXCR7, IK respectively) was previously shown to distinguish two subclasses of PTCL-NOS with distinct clinical outcomes6,27. This evidence concerns the gene IK and mature T-cell and NK-cell non-Hodgkin lymphoma.