The myeloproliferative neoplasms: insights into molecular pathogenesis and changes in WHO classification and criteria for diagnosis.

In the 2008 World Health Organization-sponsored classification of hematopoietic and lymphoid malignancies, changes were made in the classification and criteria for the diagnosis of some of the myeloproliferative disorders. These changes were initiated by recent insights into the molecular pathogenesis of these disorders. In this article, the changes made to the myeloproliferative neoplasm and the basis of the new classification and altered diagnostic criteria are summarized and discussed.