The figure illustrates the diagnostic methods in AML with t(8;21) in clockwise direction. Diagnostic workup includes morphology (center panel) and flow cytometry, as well as cytogenetics and fluorescence in situ hybridization (FISH). Polymerase chain reaction–based assays allow specific detection of fusion transcripts. MRD monitoring with highly sensitive assays (eg, quantitative polymerase chain reaction [qPCR]) are standard. With the increasing knowledge of additional gene mutations and the genetically unstable behavior of this disease during follow-up and relapse, a comprehensive molecular screening (targeted sequencing) will become important.