Incidence and significance of the JAK2 V617F mutation in patients with chronic myeloproliferative disorders

The role of genotypes that modify the toxicity of chemical mutagens in the risk for myeloproliferative neoplasms

BACKGROUND

The etiology of myeloproliferative neoplasms (MPN) (polycythemia vera; essential thrombocythemia; primary myelofibrosis) is unknown, however they are associated with a somatic mutation--JAK2 V617F--suggesting a potential role for environmental mutagens.

METHODS

We conducted a population-based case-control study in three rural Pennsylvania counties of persons born 1921-1968 and residing in the area between 2000-2008. Twenty seven MPN cases and 292 controls were recruited through random digit dialing. Subjects were genotyped and odds ratios estimated for a select set of polymorphisms in environmentally sensitive genes that might implicate specific environmental mutagens if found to be associated with a disease.

RESULTS

The presence of NAT2 slow acetylator genotype, and CYP1A2, GSTA1, and GSTM3 variants were associated with an average 3-5 fold increased risk.

CONCLUSIONS

Exposures, such as to aromatic compounds, whose toxicity is modified by genotypes associated with outcome in our analysis may play a role in the environmental etiology of MPNs.

Evaluation of the JAK2-V617F gene mutation in Turkish patients with essential thrombocythemia and polycythemia vera

An activating mutation of Janus kinase 2 (JAK2-V617F) was previously described in chronic myeloproliferative disorders (MPD). In previously published studies, the frequency of the JAK2-V617F mutation was determined to be 80-90 % for patients with polycythemia vera (PV) and 40-70 % for essential thrombocythemia (ET). In this study, we analyzed the relationship between the JAK2-V617F mutation and clinical-hematological parameters in Turkish patients with MPD and compared these findings with published studies from other geographic regions. A total of 148 patients were studied; of which, 70 were diagnosed with PV and 78 with ET. The mutation status of JAK2 was determined using a tetra-primer polymerase chain reaction. We found that 80 % of the PV group and 42 % of the ET group were positive for the JAK2-V617F mutation. When all patients were analyzed, the levels of white blood cells, hemoglobin and splenomegaly were significantly different in patients with the JAK2-V617F mutation (p < 0.05). To our knowledge, this study is the first to evaluate the relationship between MPD and JAK2-V617F in Turkish patients. The JAK2-V617F mutation is frequently detected in the Turkish patients with MPD, and especially in patients with PV. Hence, it would be useful to include JAK2 mutation screening in the initial evaluation of patients suspected to have MPD.