JAK2 V617F, MPL W515L and JAK2 Exon 12 Mutations in Chinese Patients with Primary Myelofibrosis.

OBJECTIVE: JAK2 V617F, MPL W515L and JAK2 exon 12 mutations are novel acquired mutations that induce constitutive cytokine-independent activation of the JAK-STAT pathway in myeloproliferative disorders (MPD). The discovery of these mutations provides novel mechanism for activation of signal transduction in hematopoietic malignancies. This research was to investigate their prevalence in Chinese patients with primary myelofibrosis (PMF). METHODS: We introduced allele-specific PCR (AS-PCR) combined with sequence analysis to simultaneously screen JAK2 V617F, MPL W515L and JAK2 exon 12 mutations in 30 patients with PMF. RESULTS: Fifteen PMF patients (50.0%) carried JAK2 V617F mutation, and only two JAK2 V617F-negative patients (6.7%) harbored MPL W515L mutation. None had JAK2 exon 12 mutations. Furthermore, these three mutations were not detected in 50 healthy controls. CONCLUSION: MPL W515L and JAK2 V617F mutations existed in PMF patients but JAK2 exon 12 mutations not. JAK2 V617F and MPL W515L and mutations might contribute to the primary molecular pathogenesis in patients with PMF.

[Correlations of JAK2V617F point mutation with clinical and laboratory features in patients with polycythemia vera].

To evaluate JAK2V617F point mutation in patients with polycythemia vera (PV) and its clinical significance, the point mutation was detected by allele specific polymerase chain reaction (AS-PCR), and the clinical and laboratory features of 50 PV patients with JAK2V617F positive and negative mutations were analyzed and compared each other. The results showed that among 50 patients, 31 patients (62.0%) had JAK2V617F point mutation; 12 patients (24.0%) showed thrombosis and microvascular disturbances; 3 patients had chromosome karyotype abnormalities. As compared with negative mutation group, the age and leukocyte count in patients with JAK2V617F point mutation were older (57.5 +/- 10.0 vs 45.6 +/- 14.9, p < 0.05) and higher (16.2 +/- 6.7 vs 9.0 +/- 5.2, p < 0.05) respectively. It is concluded that the frequency of the JAK2V617F point mutation is 62.0% in PV patients, the age and leukocyte count of patients with JAK2V617F point mutation are older and higher respectively than those in negative mutation group.