Unlike TET2 and DNMT3A mutations that occur at the haematopoietic stem cell level, both RHOA and IDH2 mutations are restricted to the neoplastic T‐cell clone in AITL and PTCL‐TFH 7, 16, 21, 22. The gene discussed is RHOA; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.