In extension of the previously recognized PTCL-NOS subgroups of PTCL-TBX21 and PTCL-GATA3, DNMT3A-mutant patients with a concurrent PTCL-TBX21 subtype were identified to have significantly inferior OS as compared to DNMT3A-wildtype PTCL-TBX21 patients; this finding was not reproduced in the cohort of PTCL-GATA3 patients. Here, TBX21 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.