Intriguingly, a recent study from Koeffler and colleagues aimed at capturing the mutational landscape of MLL-PTD AML demonstrated that MLL-PTD mutations co-occur with several other mutations, including FLT3-ITD, DNMT3A, IDH1, TET2, cohesion genes, and splicing factors, but not NPM1 which is the most commonly mutated gene in AML (49). The gene discussed is IDH1; the disease is acute myeloid leukemia.