Clinical implications of the JAK2 V617F mutation in essential thrombocythemia.

Characterization of the molecular lesion(s) underlying the Philadelphia-negative chronic myeloproliferative disorders (MPD), including polycythemia vera (PV), essential thrombocythemia (ET), and chronic idiopathic myelofibrosis (IM), has represented a formidable task since their description. We searched for possible associations of the JAK2 V617F mutation with disease phenotype, including clinical characteristics and laboratory parameters such as endogenous erythroid colony formation (EEC), clonality status by means of the X-chromosome inactivation pattern (XCIP), PRV-1 overexpression, or platelet cMpl content, in 130 patients with ET. In summary, our data on a large population of subjects with a diagnosis of ET confirm recent observations that around half of them have the JAK2 V617F mutation in granulocytes; however, the presence of the mutation does not appear to correlate with specific clinical-laboratory characteristics, so that, apart from the diagnostic power, its role in the clinical management of patients remains to be ascertained.