TET2 and mature T-cell and NK-cell non-Hodgkin lymphoma: Frequent mutations in TET2, and sporadic mutations in TET3, have also been noted in peripheral T cell lymphoma (PTCL), including angioimmunoblastic T cell lymphoma and PTCL-NOS (PTCL, not otherwise specified) (128–130), and the malignant T cells often bear NK cell markers, thus resembling NKT cells (130).