In this study, we conducted a comprehensive phenotypic, cytogenetic, molecular and therapeutic response analysis in a large cohort of patients with AML harbouring t(8;21)/RUNX1–RUNX1T1, aiming to elucidate the relationship between leukaemic differentiation stage, genomic features and clinical outcomes. The gene discussed is RUNX1T1; the disease is acute myeloid leukemia.