Research On Expression Of JAK2V617F, MPLW515L/K Mutation And The Relationship Between JAK2V617F Mutation And Thromboembolism In Myeloproliferative Neoplasm Patients

Objective: To explore the significance of JAK2V617F and MPLW515L/K mutation in diagnosis of MPN patients and the correlation between JAK2V617F mutation and thromboembolism.Method: Genomic DNA samples extracted from bone marrow or blood monocular cells of 107 cases of MPN were screened with AS-PCR or PCR and both of JAK2V617F and MPLW515L/k mutation were detected with gel electrophoresis. There were 46 cases with polycythemia vera (PV), 43 cases with essential thrombocytosis (ET) and 18 cases with primary myelofibrosis (PMF). 34 patients were found complicated with thromboembolism in the total of 107 MPN patients among whom there were 16 in 46 PV, 14 in 43 ET, and 4 in 18 PMF. The clinical and laboratory data of 107 MPN patients were retrospectively analyzed.Results: JAK2V671F mutation was detected in 38 of the 46 patients with PV (82.6%), 23 of the 43 with ET (53.5%) and 10 of the 18 with PMF (55.6%). None of the 28 JAK2V617F negative ET and PMF patients had MPLW515L/K mutation. PV and ET patients with JAK2V617F postive had more leukocytes and higher hemoglobin levels than JAK2V617F negative patients,while PMF patients with JAK2V617F postive have more leukocytes and platelets than JAK2V617F negative patients(P<0.05). The occurrences of thromboembolism in MPN patients group with JAK2V617F positive were more than that of JAK2V617F negative group (P<0.05). Thromboembolism trends to occur to comparatively older MPN patients(P<0.05).Conclusions: JAK2V617F mutation occurs in significant percentage of Chinese patients with MPN. Patients with JAK2V617F positive have more blood cells and thus are more susceptible to thrombosis than JAK2 negative patients. Higher blood cells count of the JAK2V617F positive patients may easily lead to higher blood volume and cause Hyperviscosity of blood, thus increasing the risk of thromboembolism. In addition, age might be considered to be a risk factor that affects the occurrence of thromboembolism. How does the JAK2V617F mutation play a direct role in leading to thrombosis is worth of further study. JAK2V617F test might be used to identify whether a patient with unknown thrombosis has latent-MPN.