IDH2 and mature T-cell and NK-cell non-Hodgkin lymphoma: Several mutations in epigenetic modifying genes such as TET2, IDH2-R172, RHOA, IDH2, or DNMT3A have been reported in PTCL cases, with DNMT3A, IDH2, and TET2 mutations being the most frequent mutations identified in AITL and PTCL-NOS, and these are associated with disease progression [10,26,27].