title: Eosinophilic myeloid neoplasms.
abstract: OBJECTIVE
  In 2012, idiopathic hypereosinophilic syndrome (HES) is still the prevalent diagnosis in patients with persistent eosinophilia, in which a primary or secondary cause of eosinophilia has not been identified. HES is considered a provisional diagnosis until a primary or secondary cause of hypereosinophilia is established. The discovery of imatinib-sensitive fusion proteins in a subset of patients with hypereosinophilia has changed the way we approach the diagnosis and treatment of eosinophilic myeloid neoplasms [eosinophilic myeloproliferative neoplasms (MPNs)]. Despite the recent diagnostic developments, diagnosis of hypereosinophilic MPN is only made in 10-20% of patients with persistent primary hypereosinophilia.
  
  
  RESULTS
  In 2008 the World Health Organization (WHO) established a semi-molecular classification of hypereosinophilic MPNs. The discovery of PDGFRA, PDGFRB, FGFR1, JAK-2, and FLT3 fusion proteins in patients with eosinophilic MPNs provide opportunities for targeted therapy. Patients with hypereosinophilic MPNs associated with PDGFRA and PDGFRB fusion genes are responsive to imatinib.
  
  
  CONCLUSIONS
  Ongoing research continues to expand our understanding of the pathophysiology of persistent primary hypereosinophilia and clarify the boundaries between some of these disorders. A key challenge is to identify new targets for therapy and limit the number of patients who are classified as having HES.
authors: Division of Hematology Oncology, Mayo Clinic Arizona, Scottsdale, Arizona 85259, USA. Noel.Pierre@Mayo.edu
authors: Pierre
authors: P
authors: Noel
authors: Ruben A
authors: RA
authors: Mesa
mesh_terms: D004802:Eosinophilia / Q000378:metabolism; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000175:diagnosis* / Q000378:metabolism; D009196:Myeloproliferative Disorders / Q000175:diagnosis* / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism
chemical_list: D011505:Protein-Tyrosine Kinases