In addition, mutations in TET1, TET3, and DNMT3A were enriched in PTCL-TBX21 [2, 15], suggesting that the alterations in epigenetic regulators play an important role in pathogenesis of PTCL-TBX21 subtype. This evidence concerns the gene TET1 and mature T-cell and NK-cell non-Hodgkin lymphoma.