الفهرس 
introduction and aim of the essayOnly 14 pages are availabe for public view
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Abstract
The WHO (World Health Organization) classification system for hematological malignancies includes eight clinicopathological entities under the category of myeloproliferative neoplasms (MPNs): chronic myelogenous leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF), chronic neutrophilic leukemia, chronic eosinophilic leukemia-not otherwise specified, mastocytosis and MPN unclassifiable. In the past 5 years, a number of stem cell-derived mutations involving JAK2 (exon 14 and exon 12), Myeloproliferative Leukemia Virus (MPL) (exon 10), have been described in chronic- or blast-phase MPN . JAK2V617F is by far the most prevalent mutation in BCR-ABL- negative MPN (occurs in 95% of patients with PV, in 55% with ET and in 65% with PMF) . JAK2V617F results from a somatic G to T mutation involving JAK2 exon 14, which leads to substitution of valine to phenylalanine at codon 617. Quantitative JAK2 mutation testing not only provides prognostic information about MPN, but it can also be used to monitor disease progression and response to therapy. The JAK2 inhibitors bring great excitement to the field of Ph-negative MPDs because of their targeted approach.