The reclassification of the Acute Myeloid Leukaemias by the World Health Organisation- a mini review

The purpose of classifying acute myeloid leukaemia (AML) is to identify distinct biological entities between the individual subtypes in order to determine optimal treatment. Over the past two decades most classifications of AML have been largely based on the criteria established by the French-American-British (FAB) working group, using morphological appearance and selective cytochemical staining. The subsequent development of monoclonal antibodies enabled additional sub-classification according to immunophenotype. The discovery of a number of genetic lesions that predict clinical behaviour and outcome better than morphology and cytochemistry necessitated the incorporation of the specific genetic data into a classification scheme. In 1997, the World Health Organization (WHO) developed a new classification of haematologic malignancies which was more clinically relevant than the traditional FAB classification. The WHO classification system of AML has expanded and modified the traditional FAB-type categories to include more disease categories such as AML associated with myelodysplasia and others that have specific cytogenetic changes. The purpose of this paper is to overview the FAB and WHO classifications of AML.