[Primary myelofibrosis--pathogenesis, diagnosis and treatment]

Myeloproliferative neoplasms and JAK2 mutations

BACKGROUND

The relationship between the JAK2V617F mutation and myeloproliferative neoplasms was described in 2005, and has since paved the way for a new understanding of these diseases. The purpose of the study was to determine the prevalence of JAK2V617F in a Norwegian patient cohort assessed for myeloproliferative neoplasia, and to investigate potential clinical and biochemical differences between mutation-positive and mutation-negative patients.

MATERIAL AND METHOD

Since 2006, the Laboratory for Clinical Biochemistry at Haukeland University Hospital has been performing analyses for the JAK2V617F mutation in real time polymerase chain reactions (PCR). In the present study, we retrieved the results of all JAK2V617F mutation analyses performed in the period 2006 – 2012. The results were compared with clinical data from electronic patient records.

RESULTS

Of 803 patients who underwent analysis, 156 were found to have the mutation (19.4 %), while 216 were diagnosed as having a myeloproliferative disorder. Eighty-one of 108 patients diagnosed as having polycythaemia vera (75.0 %), 55 of 92 with essential thrombocytosis (59.8 %) and eight of 16 patients with myelofibrosis (50.0 %) had the mutation. Mutation-positive patients with polycythaemia vera had high levels of platelets and leukocytes. The age of onset of mutation-negative patients was lower, and they were more often smokers. Mutation-positive patients with essential thrombocytosis had high levels of haemoglobin, haematocrit and leukocytes.

INTERPRETATION

JAK2V617F is an essential diagnostic marker of myeloproliferative neoplasms and is associated with differences in the phenotypes of these disorders.