[Significance of WHO classification for acute leukemia and myelodysplastic syndrome]

The FAB classification, proposed in 1976, is basically a morphological classification of leukemia and is now used worldwide. However, according to chromosome and genetic research development, some important data have been revealed to influence the prognosis of leukemia. Recently, the World Health Organization (WHO), in conjunction with the Society for Hematopathology and the European Association of Hematopathology, published a new classification. The WHO classification incorporated the results of chromosome and genetic analyses of leukemia. Some leukemias and lymphomas revealed genetic abnormalities, establishing a new disease entity in the WHO classification, and several genetic abnormalities affect drug sensitivity and prognosis. As the WHO classification is going to be used worldwide, we should update our understanding of its contents.