JAK2 Mutation Helps Define Polycythemia Vera

Diagnosis of polycythemia vera (PV) is based on criteria such as elevated hemoglobin concentration and red-cell mass, normal oxygen saturation, and splenomegaly. Occasionally however, erythrocytosis secondary to a solid tumor is misdiagnosed as PV, with dire consequences. Recently, researchers have reported that an acquired mutation in the Janus Kinase 2 gene (V617F JAK2) is found in nearly all patients with PV, and the presence of this acquired mutation might be one of the most useful criteria for diagnosis of PV.

Reviewers noted that wild-type JAK2 protein is required for normal intracellular processing and cell-surface display of the erythropoietin (EPO) receptor. Mutant JAK2 protein promotes autonomous proliferation of red cells, indepen…