IDH2 Arg172, another driver mutation in epigenetic regulation, is observed in 20–30% of AITL cases and rarely in other nTFHL subtypes [15, 16], whereas the RHOA Gly17Val mutation, specific for nTFHL, occurs in ~50–70% of cases [4–6]. This evidence concerns the gene IDH2 and angioimmunoblastic T-cell lymphoma.