Classification and diagnosis of myeloproliferative neoplasms according to the 2008 World Health Organization criteria

Prevalence of High-Altitude Polycythemia and Hyperuricemia and Risk Factors for Hyperuricemia in High-Altitude Immigrants

Song Zhen, Anxin Zhang, Jie Luo, Guanghai Xiong, Haibo Peng, Rang Zhou, Yuanfeng Li, Hongqiang Xu, Zhen Li, Wei Zhao, and Haoxiang Zhang. Prevalence of high-altitude polycythemia and hyperuricemia and risk factors for hyperuricemia in high-altitude immigrants. High Alt Med Biol. 24:132-138, 2023. Background: Few studies have investigated the epidemiology of chronic mountain sickness (CMS) in high-altitude immigrants. This study evaluated the prevalence of polycythemia and hyperuricemia (HUA) and risk factors for HUA in high-altitude immigrants. Methods: A cross-sectional study was conducted with 7,070 immigrants 15-45 years of age living on the Tibetan Plateau between January and December 2021. Information from routine physical examinations was obtained from each participant. Binary logistic regression analysis was performed to determine the correlation of several risk factors for HUA. Results: The prevalence of high-altitude polycythemia (HAPC) and HUA was 25.8% (28.7% in males and 9.4% in females) and 54.2% (59.9% in males and 22.5% in females), respectively. The highest prevalence of HAPC in males and females was observed in participants 26-30 and 21-25 years of age, respectively. The highest prevalence of HUA in both males and females was observed in participants 26-30 years of age. Binary logistic regression analysis showed that age, sex, and hemoglobin (Hb) concentration were risk factors for HUA, among which age was a negative factor and male sex and Hb concentration were positive factors. Conclusions: Immigrants are more susceptible to HAPC and HUA. The high prevalence of CMS of immigrants may be associated with Hb concentration, age, and sex.

Disabled, invisible and dismissed-The lived experience of fatigue in people with myeloproliferative neoplasms

BACKGROUND

Myeloproliferative neoplasms (MPNs) are rare haematological cancers. Several studies report the most common MPN symptom leading to reduced quality of life is fatigue. Yet, how fatigue affects the lives of people with MPN is not well described.

AIMS

The purpose of this qualitative study is to better understand the lived experience of fatigue associated with MPN.

METHODS AND RESULTS

People with MPN who had experienced fatigue were invited to complete an online survey and if eligible, then to participate in semi-structured interviews and focus groups, exploring their experiences of fatigue. Thematic analysis of interview transcripts by two researchers produced themes describing the lived experience of fatigue. Twenty-three people with MPN participated in seven interviews and four focus groups. Qualitative data revealed how fatigue significantly affected participants' experiences of functional, social, family and emotional wellbeing. Participants reported that fatigue was infrequently acknowledged or addressed by health professionals, and a lack of information or support to manage their fatigue. Four themes including 12 sub-themes describe the experience of fatigue in MPN: (1) the distress of the MPN diagnosis, (2) sensations of fatigue, (3) daily life and emotional burden with fatigue and (4) how people managed their fatigue with limited guidance.

CONCLUSION

Fatigue in MPN is common, debilitating and distressing. It affects all aspects of health, wellbeing and life. Health professionals could affect patients' lives substantially by acknowledging and understanding fatigue in MPN, including contributing factors and potential opportunities for management. More systematic data describing the causes and management of MPN fatigue is needed.

Patterns of Care for Older Patients With Myelofibrosis: A Population-based Study

BACKGROUND

Current treatments for myelofibrosis (MF) are largely palliative, with the JAK inhibitor ruxolitinib being the breakthrough approved for higher-risk patients by the United States Food and Drug Administration in November 2011. There are limited data on the "real-world" clinical experiences among patients with MF who are treated in the JAK inhibitor era.

PATIENTS AND METHODS

We evaluated patterns of care for older patients with MF before and after ruxolitinib approval, using the Surveillance, Epidemiology, and End Results-Medicare database. Treatment patterns were assessed using Medicare part B and D claims.

RESULTS

This study included 528 patients diagnosed during 2007 to 2015, with a median age at diagnosis of 76 years. Among 298 patients diagnosed in the ruxolitinib era (2012-2015), 113 (37.9%) were ruxolitinib users. Similar numbers of users started ruxolitinib at 5, 10, 15, or 20 milligrams twice a day (BID). Among 31 patients starting at 5 milligrams BID or less, 48.4% were unable to escalate the dose, and < 11 users could increase the dose to the maximum 25 mg BID. Approximately one-half of ruxolitinib users took hydroxyurea and/or prednisone simultaneously with ruxolitinib. The median time on ruxolitinib was 11.9 months (interquartile range, 4.2-21.7 months).

CONCLUSION

It would be important to optimize the use of ruxolitinib and develop new drugs that may be administered together with or after ruxolitinib to accomplish better outcomes in older patients with MF.

The Efficacy of Imatinib Mesylate in the Treatment of a Rare Lytic Bone Lesion Caused by Hypereosinophilic Syndrome/Chronic Eosinophilic Leukemia: A Case Report

CASE

We report a patient with hypereosinophilia-associated massive osteolytic lesion of the sacrum who was admitted to our hospital. Genetic analysis revealed that atypical eosinophilic cells were positive for FIP1-like-1-platelet-derived growth factor receptor-alpha (FIP1L1-PDGFRA) fusion gene. Treatment was initiated with oral administration of imatinib mesylate. The patient responded rapidly to this medication with a marked reduction in eosinophilia both from the peripheral blood and FIP1L1-PDGFRA fusion gene in the bone marrow within 2 weeks, followed by gradual osteosclerotic repair of the sacrum.

CONCLUSIONS

This case study found that the drug imatinib proved very effective in the treatment of this rare condition.

Progress in elucidation of molecular pathophysiology of myeloproliferative neoplasms and its application to therapeutic decisions

Myeloproliferative neoplasms (MPNs) are hematological diseases that are driven by somatic mutations in hematopoietic stem and progenitor cells. These mutations include JAK2, CALR and MPL mutations as the main disease drivers, mutations driving clonal expansion, and mutations that contribute to progression of chronic MPNs to myelodysplasia and acute leukemia. JAK-STAT pathway has played a central role in the disease pathogenesis of MPNs. Mutant JAK2, CALR or MPL constitutively activates JAK-STAT pathway independent of the cytokine regulation. Symptomatic management is the primary goal of MPN therapy in ET and low-risk PV patients. JAK2 inhibitors and interferon-α are the established therapies in MF and high-risk PV patients.

Reduced expression but not deficiency of GFI1 causes a fatal myeloproliferative disease in mice

Growth factor independent 1 (Gfi1) controls myeloid differentiation by regulating gene expression and limits the activation of p53 by facilitating its de-methylation at Lysine 372. In human myeloid leukemia, low GFI1 levels correlate with an inferior prognosis. Here, we show that knockdown (KD) of Gfi1 in mice causes a fatal myeloproliferative disease (MPN) that could progress to leukemia after additional mutations. Both KO and KD mice accumulate myeloid cells that show signs of metabolic stress and high levels of reactive oxygen species. However, only KO cells have elevated levels of Lysine 372 methylated p53. This suggests that in contrast to absence of GFI1, KD of GFI1 leads to the accumulation of myeloid cells because sufficient amount of GFI1 is present to impede p53-mediated cell death, leading to a fatal MPN. The combination of myeloid accumulation and the ability to counteract p53 activity under metabolic stress could explain the role of reduced GF1 expression in human myeloid leukemia.

Multicenter analysis of the use of transjugular intrahepatic portosystemic shunt for management of MPN-associated portal hypertension

BCR-ABL1-negative myeloproliferative neoplasms (MPNs) are clonal stem cell disorders defined by proliferation of one or more myeloid lineages, and carry an increased risk of vascular events and progression to myelofibrosis and leukemia. Portal hypertension (pHTN) occurs in 7-18% of MPN patients via both thrombotic and nonthrombotic mechanisms and portends a poor prognosis. Transjugular intrahepatic portosystemic shunt (TIPS) has been used in the management of MPN-associated pHTN; however, data on long-term outcomes of TIPS in this setting is limited and the optimal management of medically refractory MPN-associated pHTN is not known. In order to assess the efficacy and long-term outcomes of TIPS in MPN-associated pHTN, we performed a retrospective analysis of 29 MPN patients who underwent TIPS at three academic medical centers between 1997 and 2016. The majority of patients experienced complete clinical resolution of pHTN and its clinical sequelae following TIPS. One, two, three, and four-year overall survival post-TIPS was 96.4%, 92.3%, 84.6%, and 71.4%, respectively. However, despite therapeutic anticoagulation, in-stent thrombosis occurred in 31.0% of patients after TIPS, necessitating additional interventions. In conclusion, TIPS can be an effective intervention for MPN-associated pHTN regardless of etiology. However, TIPS thrombosis is a frequent complication in the MPN population and indefinite anticoagulation post-TIPS should be considered.

A Genetic Screen Reveals an Unexpected Role for Yorkie Signaling in JAK/STAT-Dependent Hematopoietic Malignancies in Drosophila melanogaster

A gain-of-function mutation in the tyrosine kinase JAK2 (JAK2^V617F) causes human myeloproliferative neoplasms (MPNs). These patients present with high numbers of myeloid lineage cells and have numerous complications. Since current MPN therapies are not curative, there is a need to find new regulators and targets of Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling that may represent additional clinical interventions . Drosophila melanogaster offers a low complexity model to study MPNs as JAK/STAT signaling is simplified with only one JAK [Hopscotch (Hop)] and one STAT (Stat92E). hop^{Tumorous-lethal(Tum-l)} is a gain-of-function mutation that causes dramatic expansion of myeloid cells, which then form lethal melanotic tumors. Through an F1 deficiency (Df) screen, we identified 11 suppressors and 35 enhancers of melanotic tumors in hop^Tum-l animals. Dfs that uncover the Hippo (Hpo) pathway genes expanded (ex) and warts (wts) strongly enhanced the hop^Tum-l tumor burden, as did mutations in ex, wts, and other Hpo pathway genes. Target genes of the Hpo pathway effector Yorkie (Yki) were significantly upregulated in hop^Tum-l blood cells, indicating that Yki signaling was increased. Ectopic hematopoietic activation of Yki in otherwise wild-type animals increased hemocyte proliferation but did not induce melanotic tumors. However, hematopoietic depletion of Yki significantly reduced the hop^Tum-l tumor burden, demonstrating that Yki is required for melanotic tumors in this background. These results support a model in which elevated Yki signaling increases the number of hemocytes, which become melanotic tumors as a result of elevated JAK/STAT signaling.

Rethinking the usefulness of bone marrow biopsy on treatment decision in CLL patients at diagnosis

We aimed to investigate the role of bone marrow infiltration pattern (BMIP) and bone marrow reticulin fibrosis (BMRF) in determining treatment demand in patients with diagnosis of chronic lymphocytic leukemia (CLL). We retrospectively evaluated the data of 65 patients, who were followed with the diagnosis of CLL at Istanbul Training and Research Hospital, Department of Hematology, between July 2007 and June 2016. The median age of the patients was 64 years (range, 32-83). Twenty-three (35.4%) patients were female, and 42 (64.6%) were male. Early/mild grade BMRF was observed in 46 (70.8%) patients and advanced grade BMRF in 19 (29.2%) patients. Eleven (23.9%) of 46 patients with early/mild grade BMRF and 10 (52.9%) of 19 patients with advanced grade BMRF required treatment during follow-up (p = 0.04). According to the BMIP, 14 (21.5%) patients had diffuse and 51 (78.5%) patients had non-diffuse BMIP. Eleven (78.6%) of 14 patients with diffuse BMIP and 10 (19.6%) of 51 patients with non-diffuse BMIP required treatment during follow-up (p < 0.001). In univariate analysis, both advanced grade BMRF and diffuse BMIP had an impact on occurrence of treatment demand (p = 0.028, HR = 3.535 vs. p < 0.01 HR = 15.033). Multivariate analysis also revealed diffuse BMIP to be effective (p < 0.001, HR 13.089), while advanced grade BMRF failed to significantly influence treatment demand (p = 0.140, HR 2.664). In conclusion, in the light of our findings, it is reasonable to consider that bone marrow biopsy at the time of diagnosis might provide a preliminary information about treatment demand in patients with CLL.

The JAK2V617F mutation in normal individuals takes place in differentiating cells

The JAK2V617F mutation that results in a hyper-activation of the JAK2 kinase in the erythropoietin pathway is a molecular marker for myeloproliferative neoplasms. Using allele-specific Real-Time PCR, we detected the mutation in the blood of 17.3% (17/98) of normal donors; the mutant allele burden was, however, very low (<0.01% compared to >1% in polycythemia vera). It was much higher in differentiated blood cells in the peripheral blood than in undifferentiated CD34⁺ cells. Erythropoietin-stimulated differentiation of normal CD34⁺ cells in liquid culture increased the mutation frequency by 3.34-fold. When progenitors from 9 normal donors were grown in erythropoietin-stimulated semi-solid cultures, the mutation was found in 8.69% of the colonies, but only in <3% of the JAK2 alleles in each positive colony, suggesting that the mutation occurred only in a few cells per colony. In mouse erythroleukemia cells carrying human JAK2 DNA, wild-type or JAK2V617F, the frequencies of mutations from JAK2 wild-type to JAK2V617F and vice versa increased following erythroid differentiation. These results suggest that the mutation occurs and accumulates during differentiation. We hypothesize that genetic stability, which relies on DNA repair, is efficient in normal hematopoietic stem cells but is downgraded in differentiating cells, rendering them susceptible to mutations, including JAK2V617F.

The Role of IL-33-Dependent Inflammation in the Tumor Microenvironment

There is compelling evidence that inflammation contributes to tumorigenesis. Inflammatory mediators within the tumor microenvironment can either promote an antitumor immune response or support tumor pathogenesis. Therefore, it is critical to determine the relative contribution of tumor-associated inflammatory pathways to cancer development. Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is released upon tissue stress or damage to operate as an alarmin. IL-33 has been primarily implicated in the induction of type-2 immune responses. However, recent findings have shown a role of IL-33 in several cancers where it may exert multiple functions. In this review, we will present the current knowledge on the role of IL-33 in the microenvironment of different tumors. We will highlight which cells produce and which cells are activated by IL-33 in cancer. Furthermore, we will explain how IL-33 modulates the tumor-associated inflammatory microenvironment to restrain or promote tumorigenesis. Finally, we will discuss the issues to be addressed first before potentially targeting the IL-33 pathway for cancer therapy.

Real world epidemiology of myeloproliferative neoplasms: a population based study in Korea 2004-2013

Myeloproliferative neoplasms (MPNs), with an expected increment in number, impose substantial economic and social burdens. To this end, we conducted a nationwide population-based descriptive epidemiology study. We also investigated medical cost associated with MPNs. Prevalence was the highest for essential thrombocythemia (ET) (range 4.1-9.0 per 100,000), followed by polycythemia vera (PV) (range 2.8-5.4 per 100,000) and primary myelofibrosis (PMF) (range 0.5-0.9 per 100,000). ET incurred the highest cumulative total cost at US$35 million and the most frequent hospital visits, while PMF incurred the highest average cost per person at US$5000. The mean hemoglobin level was 16.9 ± 2.2 g/dL for PV males and 15.5 ± 2.7 g/dL for PV females. Further analyses on hemoglobin levels showed the true positive rate of PV from the significantly elevated hemoglobin group (defined as >18.5 g/dL for men and >16.5 g/dL for women) was 3.01% and that of MPNs was 3.1%. Here, we provide the biggest population-based report on MPN epidemiology that can readily be used as a representative Asian data.

Physical Activity as a Nonpharmacological Symptom Management Approach in Myeloproliferative Neoplasms: Recommendations for Future Research

PURPOSE

Essential thrombocythemia, polycythemia vera, and myelofibrosis are rare chronic hematological malignancies known as myeloproliferative neoplasms (MPNs) and are characterized by deregulated myeloid lineage cell production, splenomegaly, and heterogeneous symptom profiles. MPN patients suffer from a significant symptom burden (eg, fatigue, depressive symptoms, early satiety) and an impaired overall quality of life (QoL). Current treatments typically include pharmacological approaches, which may come with additional side effects and may be limited by treatment-associated toxicities (ie, cytopenias). Nonpharmacological approaches such as physical activity may be beneficial for reducing symptom burden and improving QoL. To date, no studies have examined physical activity as a nonpharmacological approach in MPN patients despite preliminary evidence supporting its benefit in other hematological cancers. The purpose of this article is to (1) review the literature related to physical activity and specific hematological cancer subtypes and to (2) make suggestions for future research involving physical activity in MPN patients as a symptom management strategy.

METHODS

A brief review of studies examining physical activity in leukemias, lymphomas, and myelomas (excluding stem-cell transplant patients) was conducted.

RESULTS

There is preliminary evidence to suggest that physical activity may be an effective approach to improve patient-reported outcomes (fatigue, depression, anxiety, sleep), physical fitness (cardiovascular fitness, balance, body composition), and overall QoL in other hematological cancers.

CONCLUSIONS

Based on encouraging findings in other hematological cancers, future research should examine the feasibility and effectiveness of physical activity in MPN patients.

Overexpression of lncRNA NEAT1 mitigates multidrug resistance by inhibiting ABCG2 in leukemia

Leukemia is a heterogeneous clonal disorder in which early hematopoietic cells fail to differentiate and do not undergo programmed cell death or apoptosis. Less than one-third of adult patients with leukemia are managed using current therapies due to the emergence of multidrug resistance (MDR), emphasizing the need for newer and more robust approaches. Recent reports have suggested that long non-coding RNAs (lncRNAs) contribute to selective gene expression and, hence, could be manipulated effectively to halt the progression of cancer. However, little is known regarding the role of lncRNA in leukemia. Nuclear paraspeckle assembly transcript 1 (NEAT1) is a nuclear-restricted lncRNA involved in the pathogenesis of certain types of cancer. Deregulated expression of NEAT1 has been reported in a number of human malignancies, including leukemia and other solid tumors. The present study aimed to characterize the role of NEAT1 in the regulation of MDR in leukemia. Using reverse transcription-quantitative polymerase chain reaction, it was demonstrated that NEAT1 messenger RNA (mRNA) expression levels were significantly downregulated in leukemia patient samples compared with those from healthy donors. Furthermore, NEAT1 mRNA expression was repressed in a number of leukemia cell lines, including K562, THP-1, HL-60 and Jurkat cells, compared with peripheral white blood control cells, consistent with the expression observed in patients with leukemia. In addition, the transfection of a NEAT1 overexpression plasmid into K562 and THP-1 leukemia cell lines alleviated MDR induced by cytotoxic agents, such as Alisertib and Bortezomib, through inhibition of ATP-binding cassette G2. Although more robust studies are warranted, the current findings provide the basis for the use of NEAT1 as a novel promising target in the treatment of leukemia.

Presence of atypical thrombopoietin receptor (MPL) mutations in triple-negative essential thrombocythemia patients

Enrichment of atypical MPL mutations in essential thrombocythemia. MPLS204P and MPLY591N mutants are weak gain-of-function mutants.

MMP2 gene-735 C/T and MMP9 gene -1562 C/T polymorphisms in JAK2V617F positive myeloproliferative disorders

BACKGROUND

Myeloproliferative disorders (MPDs) are clonal hematologic malignancies originating at the level of the pluripotent hematopoietic stem cell. Matrix metalloproteases (MMPs) are proteolytic enzymes that contribute to all stages of malignancy progression. Genetic variants in the MMP genes may influence the biological function of these enzymes and change their role in carcinogenesis and progression. To our knowledge, this is the first investigation of associations between the -735 C/T and -1562 C/T polymorphisms in the MMP2 and MMP9 genes, respectively, and the risk of essential thrombocytosis (ET), and polycythemia vera (PV).

MATERIALS AND METHODS

The case-control study included JAK2V617F mutation positive 102 ET and PV patients and 111 controls. Polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and electrophoresis.

RESULTS

No statistically significant differences were detected between patient (ET+PV) and control groups regarding genotype distribution for MMP2 gene-735 C/T and MMP9 gene -1562 C/T polymorphisms and C/T allele frequency (p>0.050). Statistically borderline significance was observed between PV and control groups regarding genotype distribution for the MMP9 gene -1562 C/T polymorphism (p=0.050, OR=2.26, 95%Cl=0.99-5.16).

CONCLUSIONS

Consequently this study supported that CC genotype of MMP9 gene -1562 C/T polymorphism may be related with PV even if with borderline significance.

Anesthetic management of a patient with polycythemia vera undergoing emergency repair of a type-A aortic dissection and concomitant coronary artery bypass grafting: a case report

Polycythemia vera is a chronic progressive myeloproliferative disease characterized by increased circulating red blood cells, and the hyperviscosity of the blood can lead to an increased risk of arterial thrombosis. In a previous survey regarding postoperative outcomes in polycythemia vera patients, an increased risk of both vascular occlusive and hemorrhagic complications have been reported. Aortic surgery involving cardiopulmonary bypass may be associated with the development of a coagulopathy, and as a result, the occurrence of thrombotic complications should be avoided after coronary anastomosis. Thus, optimizing the hemostatic balance is an important concern for anesthesiologists. However, only a few cases of anesthetic management in polycythemia vera patients undergoing concomitant aorta and coronary arterial bypass surgery have ever been reported. Here, we experience a polycythemia vera patient who underwent an emergency repair of a type-A aortic dissection and concomitant coronary artery bypass grafting, and report this case with a review of the relevant literature.

[The impact of autophagy on proliferation of HEL cells and hematopoietic cells of polycythemia vera patients with JAK2 V617F mutation]

OBJECTIVE

To 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.

METHODS

Flow 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.

RESULTS

There 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.

CONCLUSION

There 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.

IL-33 signaling contributes to the pathogenesis of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are characterized by the clonal expansion of one or more myeloid cell lineage. In most cases, proliferation of the malignant clone is ascribed to defined genetic alterations. MPNs are also associated with aberrant expression and activity of multiple cytokines; however, the mechanisms by which these cytokines contribute to disease pathogenesis are poorly understood. Here, we reveal a non-redundant role for steady-state IL-33 in supporting dysregulated myelopoiesis in a murine model of MPN. Genetic ablation of the IL-33 signaling pathway was sufficient and necessary to restore normal hematopoiesis and abrogate MPN-like disease in animals lacking the inositol phosphatase SHIP. Stromal cell-derived IL-33 stimulated the secretion of cytokines and growth factors by myeloid and non-hematopoietic cells of the BM, resulting in myeloproliferation in SHIP-deficient animals. Additionally, in the transgenic JAK2V617F model, the onset of MPN was delayed in animals lacking IL-33 in radio-resistant cells. In human BM, we detected increased numbers of IL-33-expressing cells, specifically in biopsies from MPN patients. Exogenous IL-33 promoted cytokine production and colony formation by primary CD34+ MPN stem/progenitor cells from patients. Moreover, IL-33 improved the survival of JAK2V617F-positive cell lines. Together, these data indicate a central role for IL-33 signaling in the pathogenesis of MPNs.

Association of the ACE I/D gene polymorphisms with JAK2V617F-positive polycythemia vera and essential thrombocythemia

The renin-angiotensin system contributes to cell growth, proliferation, and differentiation in the bone marrow. We investigated the role of the ACE I/D gene polymorphism in 108 polycythemia vera (PV) and essential thrombocytosis (ET) patients who were positive for the JAK2V617F mutation, with a thrombosis group (TG) of 95 patients who had a history of vascular events, but did not have a history of myeloproliferative neoplasms and compared these to a healthy control group (CG) of 72 subjects. In the patients, II genotype and I allele frequency (p=0.009, odds ratio [OR]=9.716, 95% confidence interval [CI]=1.242-76.00, p=0.004, OR=2.019, 95% CI=1.243-3.280, respectively) were found to be higher than those in the controls. The DD genotype (p=0.021, OR=0.491, 95% CI=0.268-0.899) and D allele (p=0.004, OR=0.495, 95% CI=0.305-0.805) were found to be correlated with a decreased risk of a myeloproliferative neoplasm. These findings support the hypothesis that the ACE II genotype and I allele may be related to increased risk of ET and PV. Conversely, the DD genotype and D allele may be related to decreased risk of ET and PV. The results also indicated that the ACE I/D gene polymorphism was independent of thrombosis formation.

Bone cement augmentation procedures for spinal pathologic fractures by multiple myeloma

Efficacy and safety of bone cement augmentations for spinal pathologic fractures related to multiple myeloma, and usefulness of radionuclide studies for surgical decision were retrospectively evaluated. Forty eight vertebrae from 27 patients for bone cement augmentation procedures and 48 vertebrae from 29 patients for conservative treatment were enrolled. Clinical results using visual analogue scale (VAS) and Oswestry disability index (ODI), and radiologic results were assessed. For clinical decisions on treatment of spinal pathologic fracture, bone scan or single photon emission computed tomography was done for 20 patients who underwent surgery. Mean follow-up was 16.8 months. In terms of clinical results, immediate pain relief was superior in the operated group to that in the conservative group. ODI, maintenance of vertebral height and local kyphotic angle at the last follow-up were superior in the operated group in comparison to the conservative group. At one year follow-up, cumulative survival rate were 77.4% and 74.7% in the operated and conservative groups, respectively (log rank test> 0.05). Leakage of bone cement was noted at 10 treated vertebrae. Bone cement augmentations presented short-term pain relief for spinal pathologic fractures by myeloma with relative safety in highly selected patients, and radionuclide imaging studies were useful for the surgical decision on these procedures.

How common are myeloproliferative neoplasms? A systematic review and meta-analysis

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera (PV), essential thrombocythemia (ET), and primary(idiopathic) myelofibrosis (PMF). In this systematic review, we provide a comprehensive report on the incidence and prevalence of MPNs across the globe. Electronic databases (PubMed, EMBASE, MEDLINE, and Web of Science) were searched from their inception to August 2012 for articles reporting MPN incidence or prevalence rates. A random effects meta-analysis was undertaken to produce combined incidence rates for PV, ET, and PMF. Both heterogeneity and small study bias were assessed. Thirty-four studies were included. Reported annual incidence rates ranged from 0.01 to 2.61, 0.21 to 2.27, and 0.22 to 0.99 per 100,000 for PV, ET, and PMF, respectively. The combined annual incidence rates for PV, ET, and PMF were 0.84, 1.03, and 0.47 per 100,000. There was high heterogeneity across disease entities (I(2) 97.1-99.8%) and evidence of publication bias for ET and PMF (Egger test, P = 50.007 and P ≤ 0.001, respectively).The pooled incidence reflects the rarity of MPNs. The calculated pooled incidence rates do not reflect MPN incidence across the globe due to the high unexplained heterogeneity. Improved, widespread registration of MPNs would provide better information for global comparison of the incidence and prevalence of MPNs.

Association between thromboembolic events and the JAK2 V617F mutation in myeloproliferative neoplasms

Thrombotic complications are a major cause of death in patients with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), which are closely associated with the JAK2 V617F activating mutation. However, whether the presence of the JAK2 V617F mutation affects thrombotic risk is currently unknown, although some reports have suggested a variable association with thrombosis. Therefore, we investigated the association between JAK2 V617F and various complications, including thrombosis, in Japanese patients with MPNs. We assessed the JAK2 V617F status in 140 patients who were diagnosed or doubted as having some type of MPN by utilizing a JAK2 V617F-specific guanine-quenching probe. JAK2 V617F was detected in 31 of 51 patients (60.8%) with essential thrombocythemia, all 16 patients (100%) with polycythemia vera, 4 of 11 patients (36.4%) with primary myelofibrosis, 2 of 18 patients (11.1%) with other types of MPNs, and none of the 44 patients with doubted MPN. In the 78 patients with classical MPN, JAK2 V617F correlated with a leukocyte count ≥10,000/μl (p=0.046). Complications of thrombosis, hemorrhage, and leukemic transformation occurred in 21 (41.2%), 4 (25.0%), and 3 (27.3%) patients with classical MPN, respectively, and thrombotic events (TE) occurred more frequently in patients with JAK2 V617F than without (p=0.047). Based on these findings, initial screening for the JAK2 mutation and careful monitoring for thrombotic events should be performed in patients with MPN.

Image analysis of platelet derived growth factor receptor-beta (PDGFRβ) expression to determine the grade and dynamics of myelofibrosis in bone marrow biopsy samples

BACKGROUND

Myelofibrosis (MF) is characterized by accumulation of stromal cells and extracellular matrix. Progression of fibrosis is an important clinical issue and monitoring is required for new therapeutic approaches. Currently, the quantification is based on semiquantitative evaluation of reticulin silver stained slides. We recently reported that platelet derived growth factor receptor beta (PDGFRβ) expression in fibroblasts is a useful marker of stromal activation. PDGFRβ expression based scores represent significant differences in different MF grade which provides optimal source of quantification. In this study, slide-based measurements were performed to support correlations of PDGFRβ expression with MF grade.

METHODS

Scanned image tiles from 79 bone marrow samples (BM) with different MF grades were evaluated for PDGFRβ-related IHC parameters. Following the determination of immunopositive (brown component) and total area (region of interest) of the BM, PDGFRβ related image parameters were defined and evaluated in comparison with the classical reticulin based grading.

RESULTS

Eight PDGFRβ expression related image parameters showed excellent correlation with the MF grade (correlation coefficient ranging between 0.79 and 0.83) and with PDGFRβ score (0.76-0.87). Despite the significant sample heterogeneity, the parameters showed significant differences between fibrotic and nonfibrotic cases and between mild and advanced fibrosis. Distribution of values within a particular specimen emphasizes the heterogeneity of bone marrow involvement which may cause difficulties in semiquantitative methods.

CONCLUSIONS

Our results clearly demonstrated the correlation between MF and PDGFRβ expression considering all relevant areas in BM samples. This method provides good basis for follow-up comparison of the fibrotic samples.

[Pathomechanism and clinical impact of myelofibrosis in neoplastic diseases of the bone marrow]

Polyclonal mesenchymal cells (fibroblasts, endothelial cells, pericytes, osteoblasts, reticular cells, adipocytes, etc.) of the bone marrow create a functional microenvironment, which actively contributes to the maintenance of hemopoesis. This takes place through cellular interactions via growth factors, cytokines, adhesion molecules and extracellular matrix components, as well as through the control of calcium and oxygen concentration. Inflammatory and neoplastic diseases of the bone marrow result in pathologic interaction between hemopoietic progenitors and stromal cells. This may lead to the activation and expansion of the stroma and to the accumulation of reticulin and collagen fibers produced by mesenchymal cells. Clinically relevant fiber accumulation, termed as myelofibrosis accompanies many diseases, although, the extent and the consequence of myelofibrosis are variable in different disorders. The aim of this review is to summarize basic features of the normal bone marrow mesenchymal environment and the pathological process leading to myelofibrosis. In addition, the special features of myelofibrosis in bone marrow diseases, including myeloproliferative neoplasia, myelodysplastic syndrome and other neoplastic conditions are discussed.

Does HOXA9 Gene Expression in Egyptian Chronic Myelogenous Leukemia Patients Affect Disease Progression? A Retrospective Cohort Study

Objective: Chronic myelogenous leukemia (CML) is a clonal stem cell disease and is consistently associated with the BCR-ABL fusion gene. The chronic phase of the disease tends to pass into an accelerated phase and eventually leads to acute leukemia if left untreated. Oncoproteins necessary for leukemic transformation are both fundamentally and clinically relevant to identify as they might be new molecular targets for the development of specific anti-leukemic drugs. This study is an initial step to define the proportion of HOXA9 gene expression in some Egyptians with chronic-phase CML at diagnosis and to evaluate its relation with BCR-ABL expression and its clinical significance.

Materials and Methods: Sixty-two newly diagnosed CML patients (56 in chronic phase, 1 in accelerated phase, and 5 in blastic crises) were enrolled in the study. HOXA9 and BCR-ABL gene expressions were detected by one-step RT-PCR. ABL was chosen as a control gene to calculate HOXA9/ABL and BCR-ABL/ABL ratios from densitometric values of PCR product intensities.

Results: HOXA9 expression was encountered in 25/56 (44.6%) of newly diagnosed CML patients in the chronic phase. The median expression was 0.31 (range: 0.08-1.37) in relation to the ABL gene, with a higher frequency of expression in CML patients presenting with splenomegaly (p<0.001), high Sokal score (p<0.001), and BCR-ABL expression from the first round (p=0.004). No association could be detected with other clinical parameters, overall survival, or disease-free survival.

Conclusion: HOXA9 expression is closely related to poor prognostic factors, but we could not demonstrate its relationship to patient survival.

Conflict of interest:None declared.

Circulating endothelial cells in patients with venous thromboembolism and myeloproliferative neoplasms

Background

Circulating endothelial cells (CEC) may be a biomarker of vascular injury and pro-thrombotic tendency, while circulating endothelial progenitor cells (CEP) may be an indicator for angiogenesis and vascular remodelling. However, there is not a universally accepted standardized protocol to identify and quantify these cells and its clinical relevancy remains to be established.

Objectives

To quantify CEC and CEP in patients with venous thromboembolism (VTE) and with myeloproliferative neoplasms (MPN), to characterize the CEC for the expression of activation (CD54, CD62E) and procoagulant (CD142) markers and to investigate whether they correlate with other clinical and laboratory data.

Patients and Methods

Sixteen patients with VTE, 17 patients with MPN and 20 healthy individuals were studied. The CEC and CEP were quantified and characterized in the blood using flow cytometry, and the demographic, clinical and laboratory data were obtained from hospital records.

Results

We found the CEC counts were higher in both patient groups as compared to controls, whereas increased numbers of CEP were found only in patients with MPN. In addition, all disease groups had higher numbers of CD62E+ CEC as compared to controls, whereas only patients with VTE had increased numbers of CD142+ and CD54+ CEC. Moreover, the numbers of total and CD62+ CEC correlated positively with the white blood cells (WBC) counts in both groups of patients, while the numbers of CEP correlated positively with the WBC counts only in patients with MPN. In addition, in patients with VTE a positive correlation was found between the numbers of CD54+ CEC and the antithrombin levels, as well as between the CD142+ CEC counts and the number of thrombotic events.

Conclusions

Our study suggests that CEC counts may reveal endothelial injury in patients with VTE and MPN and that CEC may express different activation-related phenotypes depending on the disease status.

Long-term follow-up study in Budd-Chiari syndrome: single-center experience in 22 years

GOALS

We aimed to present our long-term surveillance experience in patients with Budd-Chiari syndrome (BCS), and we retrospectively evaluated the natural history, results of thrombophilia studies, and the factors related to mortality.

BACKGROUND

Primary BCS is a rare form of vascular disease, secondary to underlying thrombophilia. Because of its rarity and heterogeneous nature, there is a scarcity of knowledge about the natural history of the disease.

STUDY AND RESULTS

In 22 years, a total of 62 patients with primary BCS were followed in our tertiary hospital. We identified an acquired cause of BCS in 40 out of 62 patients (64.5%), whereas in 6 patients (9.7%), we found no identifiable cause. One or more thrombophilia causes were identified in 56 patients (90.3%). In 19 patients with myeloproliferative disease, 15 had Janus tyrosine kinase 2 mutation analysis and Janus tyrosine kinase 2 positivity was found in 10 patients. In regression analysis, portal vein thrombosis was found to be the only indicator of mortality, with an estimated instantaneous risk of 8.4.

CONCLUSIONS

In this study, we present one of the largest series of BCS in the English literature. We have shown that the multifactorial nature of underlying thrombophilia should be thoroughly investigated. In a patient with BCS, a clinician should be alert for the development or coexistence of portal vein thrombosis due to its deleterious effect on mortality.

Multiple Myeloma and Epidural Spinal Cord Compression : Case Presentation and a Spine Surgeon's Perspective

Multiple myeloma, a multicentric hematological malignancy, is the most common primary tumor of the spine. As epidural myeloma causing spinal cord compression is a rare condition, its therapeutic approach and clinical results have been reported to be diverse, and no clear guidelines for therapeutic decision have been established. Three patients presented with progressive paraplegia and sensory disturbance. Image and serological studies revealed multiple myeloma and spinal cord compression caused by epidural myeloma. Emergency radiotherapy and steroid therapy were performed in all three cases. However, their clinical courses and results were distinctly different. Following review of our cases and the related literature, we suggest a systematic therapeutic approach for these patients to achieve better clinical results.

Could hypoxia increase the prevalence of thrombotic complications in polycythemia vera?

Thromboses represent a major cause of morbidity and mortality in polycythemia vera but the contributing mechanisms are not fully described. To evaluate whether environmental conditions such as altitude/hypoxia could impact thrombosis history, we retrospectively analyzed thrombosis history in 71 polycythemia vera patients living at an elevation of 5000 feet or more in the Salt Lake City (SLC) area and 166 polycythemia vera patients living near sea level in the Baltimore (BLM) area. The SLC cohort was older with a longer disease duration. No significant differences in type of anticoagulation therapy or prothrombotic factors were present between the two cohorts. After adjusting for age, sex and disease duration, SLC patients experienced an estimated 3.9-fold increase in the odds of a history of thrombosis compared with BLM patients (95% confidence interval 1.8-7.6; P=0.0004). A history of a cardiovascular event was present in 58% of the SLC patients compared with 27% of the BLM patients (P<0.0001). Before diagnosis, thrombosis occurred in 18 and 4% of the SLC and BLM groups, respectively (P=0.003). No correlation between the JAK2 allele burden and thrombosis was observed in this study. This retrospective study suggests that even moderate hypoxia associated with 5000 feet elevation should be considered as an independent prothrombotic risk factor. This observation needs to be confirmed by prospective studies.

Efficacy and safety of pegylated-interferon α-2a in myelofibrosis: a study by the FIM and GEM French cooperative groups

Myeloproliferative neoplasm-related myelofibrosis is associated with cytopenic or proliferative phases, splenomegaly and constitutional symptoms. Few effective treatments are available and small series suggested that interferon could be an option for myelofibrosis therapy. We performed a retrospective study of pegylated-interferon α-2a (Peg-IFNα-2a) therapy in myelofibrosis. Sixty-two patients treated with Peg-IFNα-2a at 17 French and Belgian centres were included. Responses were determined based on the criteria established by the International Working Group for Myelofibrosis Research and Treatment. Mean follow-up was 26 months. Sixteen of 25 anaemic patients (64%) (eight concomitantly receiving recombinant erythropoietin) achieved a complete response and transfusion-independence was obtained in 5/13 patients (38·5%). Constitutional symptoms resolved in 82% of patients. All five leucopenic patients normalized their leucocyte counts, whereas a normal platelet count was obtained in 5/8 thrombocytopenic patients. Splenomegaly was reduced in 46·5% of patients, and complete resolution of thrombocytosis and leucocytosis were observed in 82·8% and 68·8% of patients, respectively. Side effects (mostly haematological) were mainly of grade 1-2. The only factor independently associated with treatment failure was a spleen enlargement of more than 6 cm below the costal margin. In conclusion, Peg-IFNα-2a induced high response rates with acceptable toxicity in a large proportion of patients with primary and secondary myelofibrosis, especially in early phases.

Platelet derived growth factor receptor-beta (PDGFRβ) expression is limited to activated stromal cells in the bone marrow and shows a strong correlation with the grade of myelofibrosis

Platelet derived growth factor receptor (PDGFR) is a membrane tyrosine-kinase receptor required for fibroblast activation in stromal proliferations. In order to assess the role of PDGFR in myelofibrosis (MF) we determined in 60 bone marrow biopsies the occurrence and distribution of its α and β subunits in normal and fibrotic bone marrow stroma using immunohistochemistry, and compared this with the grade of MF determined by Gömöri's silver impregnation. PDGF receptor subunits were found to be differentially expressed in the marrow parenchyma. PDGFRα expression identified megakaryocytes, endosteal and endothelial cells while PDGFRβ was virtually absent from inter-trabecular spaces in normal marrow. Activated fibroblasts characteristic for MF intensely expressed PDGFRβ but only a moderate increase in PDGFRα expression was seen. Semi-quantitative PDGFRβ immunoreactivity scores correlated well with the grade of MF in the vast majority of the MF cases (Spearman r= 0.83). Altogether, 21/60 (35.0%) cases showed a relative increase of PDGFRβ expression, compared to the MF grade, suggesting that increased stromal PDGFRβ expression occurs early and precedes reticulin and collagen fiber production during fibroblast activation. In conclusion, bone marrow PDGFRβ expression closely correlates with the grade of MF. Increased immunoreactivity for PDGFRβ occurs already in the prefibrotic stage of the disease and might allow a functional classification of the bone marrow stromal reaction.

Methylation of SOCS3 in Myeloproliferative Neoplasms and Secondary Erythrocytosis/Thrombocythemia

Objective: Myeloproliferative neoplasms (MPNs) like essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) are acquired clonal hematopoietic stem cell disorders and originate from a multipotent hematopoietic stem cell. The SOCS1 and SOCS3 genes are negative regulators of the JAK/STAT signal pathway. In this study we investigate the promoter methylation of these genes in the pathogenesis of MPNs and secondary erythrocytosis/thrombocythemia.

Materials and Methods: Promoter methylation of SOCS1 and SOCS3 genes was analyzed with methylation-specific PCR. PCR products were analyzed by agarose gel electrophoresis.

Results: No disease-specific CpG island methylation of SOCS1 was observed. Hypermethylation of the SOCS3 promoter was identified in 5 out of 19 (26.3%) PV cases, 2 out of 21 (9.5%) ET cases, 1 out of 5 (20%) PMF cases, and 9 out of 42 (21.4%) cases of secondary erythrocytosis/thrombocythemia.

Conclusion: The results revealed that promoter methylation of the SOCS3 gene suggests a possible role for SOCS3 methylation in the pathogenesis of MPNs and secondary erythrocytosis/thrombocythemia.

Conflict of interest:None declared.

Inheritance of the chronic myeloproliferative neoplasms. A systematic review

This systematic review investigated the inheritance of the classical chronic myeloproliferative neoplasms (MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) and chronic myelogenous leukemia (CML). Sixty-one articles were included and provided 135 families with a total of 341 participants distributed to various subtypes of MPN: 50% PV, 23% ET, 14% PMF, 10% CML and 3% non-MPN hematological disorder. Women developed the disease earlier than men (43.1 years vs 47.3 years; p = 0.074), while the general average age of onset was 46 years, notably younger than sporadic cases. The clinical phenotype of the families showed a homogenous (67%) and a heterogeneous (33%) pattern, with the majority being PV-PV pairs (36%) and PV-PMF pairs (17%), respectively. This observation suggests that the susceptibility gene (or genes) is not restricted to one subtype supporting the hypothesis of a mutation in an early multipotent stem cell. Furthermore, a major subgroup of families provided evidence of an autosomal dominant (AD) inheritance with reduced penetrance. This study suggests that the origin of MPNs may occur in at least three different settings: (i) a sporadic, (ii) genetic heterogeneity with polygenetic and environmental impact and (iii) a familial phenotype following an AD inheritance.

Incidence and clinical characteristics of myeloproliferative neoplasms displaying a PDGFRB rearrangement

OBJECTIVES

The myeloproliferative neoplasms displaying a PDGFRB rearrangement are rare diseases derived from a haematopoietic stem cell. The goals of the study were to assess the incidence of these disorders and to define the clinical and biological characteristics as well as the response to the imatinib therapy.

METHODS

A total of 556 patients with myeloproliferative neoplasms were studied by means of molecular cytogenetics.

RESULTS

The incidence of myeloproliferative neoplasms (MPN) with PDGFRB rearrangement was low (10 cases, 1.8% of all MPN). Most of the patients showed moderate anaemia (median Hb was 10.0 gr/dL; range from 7.5 to 13 g/dL), leukocytosis (median white blood cells was 21.7 × 10(9) /L with a range from 4 to 43 × 10(9) /L) and eosinophilia (median circulating eosinophils was 2.4 × 10(9) /L with a range of 1.1-5.7 × 10(9) /L) with a median of bone marrow infiltration cells displaying PDGFRB rearrangement of 55% (range, 37-85%). In three cases, a t(5;12) was observed while two patients showed rearrangements of 17q21 region. In two cases, a del(5)(q31) was observed. Most of the patients responded to standard dosage of imatinib, and the response was maintained in the time in those patients with a follow-up higher than 9 years.

CONCLUSIONS

The incidence of patients with PDGFRB rearrangement is low. These patients showed leukocytosis with eosinophilia and anaemia. The efficacy of imatinib therapy in patients showing PDGFRB rearrangement is high. For this reason, in all patients with MPN without any other molecular aberration, PDGFRB rearrangement should be ascertained.

Megakaryocyte pathology and bone marrow fibrosis: the lysyl oxidase connection

Megakaryocytes (MKs), the platelet precursors, are capable of accumulating DNA greater than a diploid content as part of their cell cycle. MKs have been recognized as mediating fibrosis in a subset of hematologic malignancies, including acute megakaryoblastic leukemia and a subset of myeloproliferative neoplasms. The mechanisms responsible for fibrosis remain only partially understood. Past studies highlighted the role of growth factors in such pathologies, and recently, the protein lysyl oxidase (LOX) has been implicated in proliferation of MKs, ploidy and deposition of fibers. LOX was initially characterized as a protein responsible for the intermolecular cross-linking of elastin and collagen, and in recent years it has been identified as regulator of various pathologies, such as cancer and inflammation. Here, we review recent advances in the understanding of the contribution of MKs to the progression of myelofibrosis, highlighting the newly identified role of LOX.

Dural sinus thrombosis owing to polycythaemia vera in a 12-year-old girl

Because of the rarity of dural sinus thrombosis in children with polycythaemia vera (PV), the options for diagnosis and treatment remain elusive. A 12-year-old girl was admitted with dural sinus thrombosis associated with PV, diagnosed by magnetic resonance venography. She was managed with interventional endovascular thrombolectomy and venoplasty, phlebotomy, hydroxyurea, low molecular weight heparin, and aspirin followed by warfarin. She made a good recovery without residual neurological deficit. This case highlights the importance of diagnosis and appropriate intervention with multi-modality treatments in patients with PV and thrombosis.

New pieces of a puzzle: the current biological picture of MPN

Over the last years, we have witnessed significant improvement in our ability to elucidate the genetic events, which contribute to the pathogenesis of acute and chronic leukemias, and also in patients with myeloproliferative neoplasms (MPN). However, despite significant insight into the role of specific mutations, including the JAK2V617F mutation, in MPN pathogenesis, the precise mechanisms by which specific disease alleles contribute to leukemic transformation in MPN remain elusive. Here we review recent studies aimed at understanding the role of downstream signaling pathways in MPN initiation and phenotype, and discuss how these studies have begun to lead to novel insights with biologic, clinical, and therapeutic relevance.

Fullerene derivative prevents cellular transformation induced by JAK2 V617F mutant through inhibiting c-Jun N-terminal kinase pathway

The constitutively activated mutation (V617F) of tyrosine kinase Janus kinase 2 (JAK2) is found in the majority of patients with myeloproliferative neoplasms (MPNs). The development of a novel chemical compound to suppress JAK2 V617F mutant-induced onset of MPNs and clarification of the signaling cascade downstream of JAK2 V617F mutant will provide clues to treat MPNs. Here we found that a water-soluble pyrrolidinium fullerene derivative, C(60)-bis (N, N-dimethylpyrrolidinium iodide), markedly induced apoptosis of JAK2 V617F mutant-induced transformed cells through a novel mechanism, inhibiting c-Jun N-terminal kinase (JNK) activation pathway but not generation of reactive oxygen species (ROS). Pyrrolidinium fullerene derivative significantly reduced the protein expression level of apoptosis signal-regulating kinase 1 (ASK1), one of the mitogen-activated protein kinase kinase kinases (MAPKKK), resulting in the inhibition of upstream molecules of JNK, mitogen-activated protein kinase kinase 4 (MKK4) and mitogen-activated protein kinase kinase 7 (MKK7). Strikingly, the knockdown of ASK1 enhanced the sensitivity to pyrrolidinium fullerene derivative-induced apoptosis, and the treatment with a JNK inhibitor, SP600125, also induced apoptosis of the transformed cells by JAK2 V617F mutant. Furthermore, administration of both SP600125 and pyrrolidinium fullerene derivative markedly inhibited JAK2 V617F mutant-induced tumorigenesis in nude mice. Taking these findings together, JAK2 V617F mutant-induced JNK signaling pathway is an attractive target for MPN therapy, and pyrrolidinium fullerene derivative is now considered a candidate potent drug for 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.