Myeloproliferative neoplasms (MPN) are clonal hematopoietic stem cell diseases characterized by proliferation of one or more myeloid cell lineages in the bone marrow and increased mature and immature cells in peripheral blood. As the most important discovery in recent studies of MPN, JAk2V617F mutation is considered to closely relate with the pathogenesis of MPN. The mutated JAK2 lost self-inhibition, and then, the sustained activation leads to a series of disorders in downstream signal transduction pathways, eventually resulting in malignant cell proliferation. A variety of methods have been used in quantitative/qualitative detection of JAK2V617F mutation, and researches about JAK2V617F mutation and its clinical features have also made some progress. However, it must be noted that there are still some unsolved problems, such as the role of JAk2V617F mutation in pathogenesis of MPN needs further exploration, effective targeted therapy for JAK2 is a attractive topic, and the application of JAK2V617F mutation in disease diagnosis also requires a deep research. In this review, the latest progress from different aspects is summarized briefly, including JAK2 and JAK2V617F mutation, effects of JAK2V617F mutation on the pathogenesis, clinical correlation of JAK2V617F with MPN, and targeting therapy.
Humans ; Janus Kinase 2 ; genetics ; Mutation ; Myeloproliferative Disorders ; genetics ; pathology

OBJECTIVETo detect the activity of autophagy and explore the impact on survival and proliferation of HEL cells and hematopoietic cells of polycythemia vera （PV） patients with JAK2 V617F mutation.

METHODSFlow cytometry, AO staining and Western blot methods were used to detect the autophagy activity and the expression of LC3-Ⅱ protein of JAK2 V617F+ HEL cells and hematopoietic cells of 12 newly diagnosed PV patients with JAK2 V617F mutation. HEL cells and bone marrow cells of 3 PV patients were treated with rapamycin or 3-MA to induce and inhibit autophagy, respectively. CellTiter Glo(R) method was used to detect the proliferation activity of cells.

RESULTSThere was higher level of mean LC3-Ⅱ fluorescence intensity in HEL cells (159 389 ± 29 001) than that in K562 cells (96 047 ± 24 134) (P=0.044). The formation of autophagosome in HEL cells is more than that in K562 cells detected by microscope. What's more, the level of mean LC3-Ⅱ fluorescence intensity in 12 PV patients' myeloid cells (92 842 ± 4 250) was higher than that of 15 healthy volunteers (86 633 ± 2 504) (P=0.001). The expression of LC3-Ⅱ protein was higher in PV patients' peripheral blood cells than that in healthy volunteers detected by Western blot. After treated with rapamycin 12, 24, 48 h, the activity of autophagy in HEL cells and bone marrow cells of 3 PV patients were increased and the proliferation activity was higher than the control group, the proliferation activity at 48 h were (101 413 ± 3 720), (18 744 ± 1 015), respectively. However, after treated with 3-MA 12, 24, 48 h, the activity of autophagy was decreased and the proliferation activity was lower than the control group, the proliferation activity at 48 h were (5 732 ± 166), (5 371 ± 56), respectively.

CONCLUSIONThere is high basical activity of autophagy in JAK2 V617F+ HEL cells and hematopoietic cells of PV patients with JAK2 V617F mutation. Up-regulated autophagy promotes proliferation of JAK2 V617F⁺ HEL cells and bone marrow cells of PV patients with JAK2 V617F mutation. Decreased autophagy inhibits proliferation of JAK2 V617F+ HEL cells and bone marrow cells of PV patients with JAK2 V617F mutation.

Humans ; Janus Kinase 2 ; Leukemia, Myeloid, Acute ; Mutation ; Thrombocythemia, Essential

Humans ; Thrombocythemia, Essential/therapy* ; Platelet Count ; Janus Kinase 2

Classical myeloproliferative neoplasm (MPN) related thrombosis mainly affects elderly patients and often involves arterial circulation, while, MPN-visceral venous thrombosis (SVT) mainly affects young women, and is closely associated with JAK2V617F mutation but not closely with CALR mutation. The pathogenesis of MPN-SVT is not only related to JAK2V617F mutation and vascular endothelial damage, but also needs further research to determine the machanism. JAK2V617F mutation is the most common in MPN-SVT clinically. Patients with non-cirrhotic SVT need to detect MPN mutation, while the detection of CALR or MPL mutation needs to be combined with clinical judgment. At present, the main treatment strategies of MPN-SVT are JAK inhibitors, supplementation of anticoagulants and treatment of portal hypertension. This article reviews the latest research progress on the epidemiology, pathogenesis, diagnosis and treatment strategies of MPN-SVT.
Aged ; Anticoagulants ; Female ; Humans ; Janus Kinase 2/genetics* ; Janus Kinase Inhibitors ; Mutation ; Myeloproliferative Disorders/genetics* ; Neoplasms ; Thrombosis ; Venous Thrombosis

BACKGROUND: Recently, myeloproliferative leukemia (MPL) W515 mutations have been reported to be molecular markers for myeloproliferative neoplasms (MPNs). We studied the association between MPL W515 mutations and the clinico-hematological features of patients with MPNs. METHODS: Our study included 154 consecutive patients diagnosed with MPNs (31 had polycythemia vera [PV]; 106, essential thrombocythemia [ET]; and 17, primary myelofibrosis [PMF]). MPL W515 mutations were detected by real-time PCR and direct sequencing methods. RESULTS: The MPL W515L mutation was found in 4 patients and the MPL W515A mutation was detected in 1 patient. These 5 patients were diagnosed with JAK2 V617F-negative ET, and they accounted for 12.5% of patients with JAK2 V617F-negative ET. The patients with MPL W515-positive ET showed significantly lower hemoglobin levels and WBC counts than did patients with MPL W515-negative ET or JAK2 V617F-positive ET. CONCLUSIONS: MPL W515 mutation is a useful diagnostic marker for JAK2 V617F-negative MPNs and it is associated with specific hematologic characteristics such as lower hemoglobin levels and WBC counts.
Humans ; Janus Kinase 2 ; Leukemia ; Polycythemia Vera ; Primary Myelofibrosis ; Real-Time Polymerase Chain Reaction ; Thrombocythemia, Essential

JAK2V617F is a novel oncogene involved in myeloproliferative neoplasms (MPN) and closely related to its vascular complications. Recent researches found the vascular endothelial injury in patients with MPN. It is increasingly being recognized that endothelial cells and endothelial progenitor cells (EPC) play an important role in MPN. Here, the pathogenesis of the EPC JAK2V617F mutation and peripheral blood EPC counts in patients with MPN or with vascular complications are reviewed.
Endothelial Cells ; Endothelial Progenitor Cells ; Humans ; Janus Kinase 2 ; Mutation ; Myeloproliferative Disorders

OBJECTIVETo investigate the clinical and laboratorial features of primary myelofibrosis (PMF) patients treated in our hospital, to analyze the risk factors influancing survival, and to compare several prognostic scoring systems.

METHODSparameters about clinical and laboratorial features were taken from medical documents at diagnosis, univariate analysis was conducted by Kaplan-Meier method, the survival data were compared with Log-rank test, and a COX model was used for multivariate analyses.

RESULTSIn our center the anemia and JAK2V617F mutation were more common, while the abnormal karyotype was less common, the constitutional symptoms, splenomegaly, Hb level < 100 g/L and LDH are adverse factors for survival in univariate analysis. Constitutional symptoms and Plt count < 100 × 10(9)/L are adverse factors of survival according to multivariate analysis.

CONCLUSIONThe anemia is more frequent in Chinese patients. Constitutional symptoms and Plt count < 100 × 10(9)/L are independent risk factors for survival. LILLI, modified IPSS, modified DIPSS are suitable to our data.

Jauns kinase (JAK)/transducer and activator of transcription（STAT） pathway is a classical approach to study the rapid changes of the gene expression in specific target cells by a variety of extracellular signals. The JAK and STAT transfer cytokine receptor signaling plays a unique role in multiple cellular and molecular biological changes.The abnormal signal of JAK/STAT pathway will lead to the hematopoietic abnormalities.Studies had shown that the abnormal activation of JAK2/STAT signaling pathway are in many kinds of malignant hematological diseases, such as in acute lymphoblastic/myeloid leukemia, chronic myeloid leukemia, lymphoma, myelodysplastic syndromes, myeloprofilerative neoplasm, especially in the patients of myeloproliferative neoplasm(MPN) with JAK gene mutation(JAK2V617F), this mutation has an important value for MPN diagnosis. At present, the effect of the specific inhibitors of JAK2 has showed good perspective, which had been applied to clinic treatment and achieved remarkable curative effect. In this review, the JAK2/STAT signaling transduction, the JAK2 signal and hematologic malignancies, the kagulation of signaling pathway and the inhibitors of JAK2/STAT signaling pathway are summarized.
Hematologic Neoplasms ; Humans ; Janus Kinase 2 ; Mutation ; STAT Transcription Factors ; Signal Transduction

This study was purposed to investigate the feasibility of high resolution melting (HRM) in the detection of JAK2V617F mutation in patients with myeloproliferative neoplasm (MPN). The 29 marrow samples randomly selected from patients with clinically diagnosed MPN from January 2008 to January 2011 were detected by HRM method. The results of HRM analysis were compared with that detected by allele specific polymerase chain reaction (AS-PCR) and DNA direct sequencing. The results showed that the JAK2V617F mutations were detected in 11 (37.9%, 11/29) cases by HRM, and its comparability with the direct sequencing result was 100%. While the consistency of AS-PCR with the direct sequencing was moderate (Kappa = 0.179, P = 0.316). It is concluded that the HRM analysis may be an optimal method for clinical screening of JAK2V617F mutation due to its simplicity and promptness with a high specificity.
Bone Marrow Neoplasms ; genetics ; Female ; Humans ; Janus Kinase 2 ; genetics ; Male ; Mutation ; Myeloproliferative Disorders ; genetics