Today, several genetic mouse models mimic Tfh PTCL/AITL in terms of clinical, pathological, histological, transcriptional, genetic and immunophenotypic features: they are based on the knockout of Tet2 and overexpression of RhoAG17V [11, 44], based on Tet2 and IDH2 mutations [13] and our transgenic mouse model is based on GAPDH overexpression in the T cell lineage [15]. The gene discussed is IDH2; the disease is angioimmunoblastic T-cell lymphoma.