Flow cytometry (FCM) in myeloid malignancies

Abstract

Myelodysplasic syndromes (MDS) and acute myeloid leukaemia (AML) are the predominant myeloid neoplasms where FCM has both a diagnostic and prognostic role in addition to minimal residual disease (MRD) testing in AML. Criteria for the diagnosis and classification of MDS have been refined and proposed in a consensus International MDS Working Group publication (2007) with immunophenotyping recommended as a co-criterion for diagnosis. Utilising our understanding and delineation of normal antigen maturation and expression patterns of myelomonocytic precursors enables the detection of aberrancy in mature and immature populations. This forms the basis of reporting MDS and AML MRD FCM. There is a large body of literature supporting the routine utility of immunophenotyping in the diagnostic workup of MDS and provocative data in patients treated serially with hypomethy-lating agents. However, further validation and definitions of aberrancy and flow scoring systems are required to enable the introduction of immunophenotyping into mainstream diagnostic laboratories. Standardisation efforts are underway within the European LeukemiaNet. FCM is routinely used for the diagnosis of AML, however MRD testing requires significant expertise. Despite numerous publications demonstrating prognostic significance in MRD at both post induction and post consolidation time points, most are single institution studies highlighting the sophistication required by laboratories.