Chronic myeloid neoplasms

Myeloproliferative neoplasms (MPNs) and related chronic disorders constitute a subgroup of myeloid malignancies which are defined according to clinical, morphological and molecular features by the actual World Health Organization classification of tumors of the haematopietic system. Screening procedures for a BCR-ABL fusion gene, JAK2, thrombopoietin receptor and KIT mutations are formally included in the diagnostic approach. Myelodysplastic/MPN overlap syndromes include rare entities such as refractory anemia with ringed sideroblasts characterized by a high proportion of JAK2V617F mutated cases. The paradigm of targeted treatment of chronic myeloid leukemia with imatinib has now been extended to eosinophilia-associated myeloid neoplasms with PDGFRA, PDGFRB or FGFR1 gene mutations. Pegylated interferon-alpha has convincingly been proved to reduce the JAK2 allele burden. JAK2 inhibitor drugs are currently being tested in clinical trials. The development of pathogenesis-targeted diagnostic and therapeutic approaches to the various MPNs will continue in the future.