Pathology consultation on myeloproliferative neoplasms

In 2008, the World Health Organization (WHO) revised the classification system for myeloproliferative neoplasms (MPNs). MPNs include chronic myelogenous leukemia, essential thrombocythemia, polycythemia vera, primary myelofibrosis, and several other disorders. The newer classification system incorporates mutations discovered in the JAK2 and MPL genes. The importance of understanding the role of mutations in JAK2, MPL, and other genes that have been discovered in MPNs is highlighted by the change in the 2008 WHO MPN classification system. Moreover, the development of highly specific inhibitors of JAK2 further stresses the importance of molecular testing in MPN diagnosis and prognosis.