In AITL and other Tfh lymphomas, TET2 (and DNMT3) mutations are often (7 of 10 cases by 1 group [20, 21] and 4 of 7 cases by another [29]) identified in normal-appearing bone marrow cells, CD34+ cells, and colony-forming blood progenitor cells. Here, TET2 is linked to angioimmunoblastic T-cell lymphoma.