From the Department of Pathology, University of Chicago, Chicago, Illinois
Author's disclosure of potential conflicts of interest is found at the end of this article.
Address reprint requests to James W. Vardiman, MD, Department of Pathology, University of Chicago, 5841 S. Maryland Avenue, MC 0008, Chicago, IL 60637-1470; e-mail: James.Vardiman{at}uchospitals.edu
Overview: Recently, novel JAK2 or MPL mutations have been described in the majority of patients with BCR–ABL-negative myeloproliferative neoplasms, polycythemia vera, essential thrombocythemia, and primary myelofibrosis. In other BCR–ABL-negative myeloproliferative neoplasms, the myeloid cells of some patients with eosinophilia harbor rearrangements of platelet-derived growth factor receptor A, platelet-derived growth factor receptor B, or fibroblast growth factor receptor 1, whereas mast cell disease is often associated with a KIT mutation. Such genotype–phenotype correlations underscore the importance of molecular information in complementing histologic diagnosis in myeloproliferative neoplasms. In this article, these issues will be discussed in the context of recent revisions proposed for the World Health Organization classification of the myeloid neoplasms, and practical diagnostic algorithms based on molecular markers — as well as on clinical and histologic findings — will be provided.
