JAK2V617F mutation and allele burden are associated with distinct clinical and morphological subtypes in patients with essential thrombocythaemia

Abstract

Essential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) that primarily involves the megakaryocytic lineage.1 The JAK2V617F mutation has been detected in 50–60% of ETs, and homozygous mutation in only 5%.2 JAK2V617F mutation has been associated with a polycythaemia vera (PV)-like phenotype3 and increased risk of thrombosis,4 especially in homozygous patients.5 Increasing mutant allele load was correlated with older age, splenomegaly, microvessel symptoms and higher frequency of arterial thrombosis at diagnosis.2 Little is known on the association between JAK2V617F mutation and histological changes in bone marrow biopsy (BMB) of ET patients. One hundred and three consecutive patients with newly diagnosed ET, admitted to the Division of Haematology, S. Giovanni Hospital and University of Turin, Italy, from 2006 to 2010 were included in the study. Diagnosis of ET was performed according to WHO criteria.1 A general informed consent was obtained according to the local ethical committee guidelines. There were 56 women and 47 men; the mean age was 59.1 years (range, 25–86). Splenomegaly was detected in 38 patients (36.9%). Venous or arterial thrombosis (confirmed by ultrasound examination or CT scan and D-dimer assessment) were found in 21% and 7% of patients, respectively. …