To date, at least 135 fusion partners of KMT2A have been described, with MLLT3, MLLT4, MLLT10, and MLLT1 being the commonest ones in KMT2A-r acute myeloid leukemia (AML), and they were also clinically and biologically heterogenous.2,3 Despite great advances in molecular biology in recent years, the prognosis of KMT2A-r AML did not improve much. Here, MLLT1 is linked to acute myeloid leukemia.