Chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) is a myeloproliferative neoplasm caused by a rearrangement of the long arms of chromosome 9 and 22, resulting in the Philadelphia (Ph) chromosome, creating the fusion oncogene BCR-ABL1. It usually presents in chronic phase, characterised by leucocytosis, predominantly neutrophilia but also basophila, eosinophilia and thrombocytosis. If untreated, it leads eventually to a blastic phase indistinguishable morphologically from acute leukaemia. Optimal management, including treatment with tyrosine kinase inhibitors, however, has led to a life expectancy similar to that of aged-matched populations. This chapter describes the molecular pathology and clinical features of CML, followed by principles of management and disease monitoring.