JAK2 V617F mutation status of 232 patients diagnosed with chronic myeloproliferative neoplasms.

INTRODUCTION/BACKGROUND: The aim of this study was to investigate the presence of Janus kinase 2 (JAK2) V617F mutation in patients with break point cluster region-abelson negative chronic myeloproliferative neoplasms (CMPNs) in our center. PATIENTS AND METHODS: We compared patients with and without the mutation, and also patients with the homozygous and heterozygous mutation, in terms of different clinical and laboratory features. RESULTS: The JAK2 V617F mutation was detected in 77 (95%), 88 (68%), and 17 (77%) of polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) patients, respectively. Among JAK2 V617F-positive patients, the homozygous genotype was found in 39 (50.6%) of the 77 PV, 23 (26.1%) of the 88 ET, and 11 (64.7%) of the 17 PMF patients. Bleeding was seen in 14 (6%) of all patients. Upper gastrointestinal bleeds were the most common, seen in 11 patients. Out of 232 CMPN patients, 44 (19%) had thrombosis. The most common thrombotic event was transient ischemic attack (52%). Progression to myelofibrosis was seen in 1 (1.2%) PV and 3 (2.3%) ET patients, and progression to acute leukemia was seen in 2 (2.5%) PV and 3 (2.3%) ET patients. Three patients with PV (3.7%), 3 with ET (2.7%), and 5 with PMF (2.7%) died during follow-up. CONCLUSION: JAK2 V617F mutation frequencies in our PV and ET patients were similar to those reported previously. JAK2 V617F mutation frequency in our PMF patients was greater than in previous reports. All of our PV patients with thrombosis and most of our ET patients with thrombosis (76.1%) were JAK2 V617F mutation-positive. This mutation seems to be correlated with thrombosis risk.