SETD2 and Sezary syndrome: We focussed on the SETD2 phenotype as inactivating SETD2 mutations are recurrent in clinically important subtypes of PTCL that may be underrepresented in clinical trials due to their rarity (e.g., Monomorphic epitheliotropic intestinal T-cell lymphoma [MEITL], γδ hepatosplenic T-cell lymphoma [γδ HSTCL] and Sézary syndrome) [7, 35].