Within the leukemias, one can differentiate BCR–ABL1-positive acute lymphocytic leukemia (ALL), as well as Ph-like variants (T127, T137, T139 and descendents) and distinct subclusters driven by fusions in CBFB–MYH11 (T145), PML–RARA (T147), TCF3–PBX1 (T135) and RBM15–MKL1 (T515), as well as acute myeloid leukemia (AML) with KMT2A internal tandem duplications (T153), KMT2A rearrangements (T159) and additional leukemia subtypes (Supplementary Fig. 8). The gene discussed is TCF3; the disease is acute myeloid leukemia.