Allogeneic stem cell transplant vs.Janus kinase inhibition in the treatment of primary myelofibrosis or myelofibrosis after essential thrombocythemia or polycythemia vera

Primary myelofibrosis is one of the Philadelphia chromosome-negative myeloproliferative neoplasms and is the member of that group with the worst survival and the most significant limitations in quality of life. Hepatosplenomegaly due to extramedullary hematopoiesis, constitutional symptoms, and cytopenias are the main manifestations. The natural history is highly variable, and up to 30% of patients can experience acceleration to acute myelogenous leukemia. Conventional therapy is only palliative and not always effective. However, huge advances have been achieved in the past 2 decades toward a better understanding of the pathogenesis of this disease, as well as improved management. Powerful risk stratification systems are now available and can reliably separate the patients into different prognostic categories to aid clinical management. Allogeneic stem cell transplant can offer cure but is still not universally applicable owing to the treatment-related mortality and toxicity. Nevertheless, outcomes of transplant are improving, owing to the introduction of reduced-intensity conditioning regimens and the optimization of remission monitoring techniques and relapse prevention strategies. The discovery of the V617F mutation of JAK2 (Janus kinase 2) and some other molecular aberrations has shed more light on the molecular pathogenesis of the disease and has led to the introduction of novel therapies such as JAK2 inhibitors. In fact, JAK inhibitors have shown promising symptomatic efficacy, and the JAK inhibitor ruxolitinib has also shown a potential survival benefit. Future effort should be made to combine allogeneic stem cell transplant with JAK inhibition.

Myeloproliferative and thrombotic burden and treatment outcome of thrombocythemia and polycythemia patients

Prospective studies indicate that the risk of microvascular and major thrombosis in untreated thrombocythemia in various myeloproliferative neoplasms (MPN-T) is not age dependent and causally related to platelet-mediated thrombosis in early, intermediate and advanced stages of thrombocythemia in MPN-T. If left untreated both microvascular and major thrombosis frequently do occur in MPN-T, but can easily be cured and prevented by low dose aspirin as platelet counts are above 350 × 10(9)/L. The thrombotic risk stratification in the retrospective Bergamo study has been performed in 100 essential thrombocythemia (ET) patients not treated with aspirin thereby overlooking the discovery in 1985 of aspirin responsive platelet-mediated arteriolar and arterial thrombotic tendency in MPN-T disease of ET and polycythemia vera (PV) patients. The Bergamo definition of high thrombotic risk and its persistence in the 2012 International Prognostic Score for ET is based on statistic mystification and not applicable for low and intermediate MPN-T disease burden in ET and PV patients on aspirin. With the advent of molecular screening of MPN patients, MPN-T disease associated with significant leukocytosis, thrombocytosis, constitutional symptoms and/or moderate splenomegaly are candidates for low dose peglyated interferon (Pegasys(R), 45 μg/mL once per week or every two weeks) as the first line myeloreductive treatment option in JAK2(V617F) mutated MPN-T disease in ET and PV patients. If non-responsive to or side effects induced by IFN, hydroxyurea is the second line myelosuppressive treatment option in JAK2(V617F) mutated ET and PV patients with increased MPN-T disease burden.

Chronic myelomonocytic leukemia: Forefront of the field in 2015

Chronic myelomonocytic leukemia (CMML) includes components of both myelodysplastic syndrome and myeloproliferative neoplasms and is associated with a characteristic peripheral monocytosis. CMML is caused by the proliferation of an abnormal hematopoietic stem cell clone and may be influenced by microenvironmental changes. The disease is rare and has undergone revisions in its classification. We review the recent classification strategies as well as diagnostic criteria, focusing on CMML's genetic alterations and unique pathophysiology. We also discuss the latest molecular characterization of the disease, including how molecular factors affect current prognostic models. Finally, we focus on available treatment strategies, with a special emphasis on experimental and forthcoming therapies.

Acute Myeloid Leukemia and Other Types of Disease Progression in Myeloproliferative Neoplasms

OBJECTIVES

This session of the Society for Hematopathology/European Association for Haematopathology workshop focused on disease progression in myeloproliferative neoplasms (MPNs).

METHODS

The session included typical and unusual presentations of chronic myelogenous leukemia (CML), BCR-ABL1 positive; Philadelphia chromosome-negative (Ph-neg) MPNs; and mastocytosis.

RESULTS

Cases of CML illustrated various manifestations of progression, with emphasis on criteria defining stages of the disease. Issues were discussed related to the patterns of recurrence in patients receiving tyrosine kinase inhibitor therapy, including leukemic transformation occurring in a Ph-neg clone. Ph-neg MPN cases highlighted diagnostic approaches used to establish accelerated and blast phases, including cases with significant myelofibrosis and when an adequate bone marrow aspirate smear is not available. The session also included rare cases of aggressive mastocytosis.

CONCLUSIONS

There was agreement that a definitive diagnosis can be challenging in the absence of documented review of prior diagnostic material and clinical history.

Toward point-of-care testing for JAK2 V617F mutation on a microchip

Molecular genetics now plays a crucial role in diagnosis, the identification of prognostic markers, and monitoring of hematological malignancies. Demonstration of acquired changes such as the JAK2 V617F mutation within myeloproliferative neoplasms (MPN) has quickly moved from a research setting to the diagnostic laboratory. Microfluidics-based assays can reduce the assay time and sample/reagent consumption and enhance the reaction efficiency; however, no current assay has integrated isothermal amplification for point-of-care MPN JAK2 V617F mutation testing with a microchip. In this report, an integrated microchip that performs the whole human blood genomic DNA extraction, loop-mediated isothermal nucleic acid amplification (LAMP) and visual detection for point-of-care genetic mutation testing is demonstrated. This method was validated on DNA from cell lines as well as on whole blood from patients with MPN. The results were compared with those obtained by unlabeled probe melting curve analysis. This chip enjoys a high accuracy, operability, and cost/time efficiency within 1h. All these benefits provide the chip with a potency toward a point-of-care genetic analysis. All samples identified as positive by unlabeled probe melting curve analysis (n=27) proved positive when tested by microchip assay. None of the 30 negative controls gave false positive results. In addition, a patient with polycythemia vera diagnosed as being JAK2 V617F-negative by unlabeled probe melting curve analysis was found to be positive by the microchip. This microchip would possibly be very attractive in developing a point-of-care platform for quick preliminary diagnosis of MPN or other severe illness in resource-limited settings.

CALR mutations screening in wild type JAK2(V617F) and MPL(W515K/L) Brazilian myeloproliferative neoplasm patients

Some myeloproliferative neoplasm (MPN) patients harbor JAK2(V617F) mutation, and CALR mutations were recently discovered in wild type (WT) JAK2(V617F). We evaluated the frequency and type of CALR mutations, and clinical and hematological characteristics in WT JAK2(V617F) and MPL(W515K/L) MPN patients. Sixty-five patients were included: 21 with primary myelofibrosis (PMF), 21 with myelofibrosis post-essential thrombocythemia (MPET) and 23 with essential thrombocythemia (ET). Screening for JAK2(V617F) and MPL(W515K/L) were performed using real-time PCR, while CALR mutations were analyzed by fragment analysis and Sanger sequencing. JAK2(V617F) was the most frequent mutation (54.5%) and one patient (1.5%) harbored MPL(W515L). CALR mutations were present in 38.1% of PMF, 12.5% of ET and 33.3% of MPET patients. Five types of CALR mutations were detected, among which type 1 (32.1%) and type 2 (21.4%) were found to be the most common. A novel CALR mutation in a PMF patient was found. Patients carrying CALR mutations had higher platelet count and less presence of splenomegaly than JAK2(V617F), while triple negatives had higher C-reactive protein levels than CALR mutant carriers. Screening for CALR mutations and its correlation with clinical features could be useful for the characterization of MPN patients and result in its incorporation into a new prognostic score.

Nuclear factor-erythroid 2, nerve growth factor receptor, and CD34-microvessel density are differentially expressed in primary myelofibrosis, polycythemia vera, and essential thrombocythemia

Because of the presence of various overlapping findings, the discrimination of polycythemia vera (PV) from prefibrotic/fibrotic primary myelofibrosis (PF/F-PMF) and essential thrombocythemia (ET) may be challenging, particularly in suboptimal bone marrow biopsy specimens. In this study, we assessed whether differences in the expression of nuclear factor-erythroid 2 (NF-E2), nerve growth factor receptor (NGFR; CD271), CD34, CD68, p53, CD3, CD20, and CD138 by immunohistochemistry could be useful in separating among them. Higher frequencies of nuclear positive erythroblasts with NF-E2 were observed in ET and PV cases (50% ± 13.3% and 41.5% ± 9.4%, respectively) when compared with both PF-PMF (21% ± 11.7%) and F-PMF (28.5% ± 10.8%). We found that with a cutoff level of at least 30% nuclear staining for NF-E2 in erythroblasts, we could reliably exclude the possibility of PMF. Conversely, NGFR+ stromal cells per high-power field (HPF) was significantly increased in F-PMF (53.5 ± 19.1/HPF) and PF-PMF (13.5 ± 3.8/HPF) compared with ET (4.4 ± 2.2/HPF) and PV (6.6 ± 3.3/HPF). Similarly, differences in CD34-microvessel density was remarkable in F-PMF and PF-PMF cases in comparison with PV and ET (49.9 ± 12.1/HPF, 29.3 ± 12.4/HPF, 13.7 ± 4.6/HPF, and 11.9 ± 5.1/HPF, respectively). Thus, the assessment of NF-E2 and NGFR expression and the evaluation of CD34-microvessel density may provide additional support in reaching a correct diagnosis in these cases of myeloproliferative neoplasms.

9H-Carbazole-1-carboxamides as potent and selective JAK2 inhibitors

The discovery, synthesis, and characterization of 9H-carbazole-1-carboxamides as potent and selective ATP-competitive inhibitors of Janus kinase 2 (JAK2) are discussed. Optimization for JAK family selectivity led to compounds 14 and 21, with greater than 45-fold selectivity for JAK2 over all other members of the JAK kinase family.

CALR, JAK2, and MPL mutation profiles in patients with four different subtypes of myeloproliferative neoplasms: primary myelofibrosis, essential thrombocythemia, polycythemia vera, and myeloproliferative neoplasm, unclassifiable

OBJECTIVES

We investigated mutation profiles of CALR, JAK2, and MPL in 199 Korean patients with myeloproliferative neoplasms (MPNs).

METHODS

In total, 199 patients with MPN (54 primary myelofibrosis [PMF], 79 essential thrombocythemia [ET], 58 polycythemia vera [PV], and eight MPN-unclassifiable [MPN-U]) and 4 patients with acute panmyelosis with myelofibrosis (APMF) were retrospectively subjected to Sanger sequencing for CALR, JAK2, and MPL.

RESULTS

The overall frequency of CALR mutations was 12.6% (type 1 mutation, 16 patients; type 2 mutation, nine patients): most frequent in MPN-U (37.5%), followed by ET (17.7%) and PMF (14.8%). CALR mutations were not found in PV or APMF. CALR and JAK2 or MPL mutations were mutually exclusive. In PMF, the CALR mutations were associated with lower levels of leukocytes, lower bone marrow cellularity, and higher number of megakaryocytes. Patients with CALR-mutated ET more frequently progressed to the accelerated or blast phases compared with patients with JAK2 mutations. CALR mutations were frequently observed in the JAK2-negative MPNs, most frequently in MPN-U.

CONCLUSIONS

The prognostic significance of CALR mutations likely differs among the MPN subtypes.

Increased likelihood of post-polycythemia vera myelofibrosis in Ph-negative MPN patients with chromosome 12 abnormalities

Chromosome 12 (Chr12) abnormalities have been described for individual patients with Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-neg MPN), however the frequency, characteristics, and outcomes of such patients as a whole have not been investigated. We reviewed a database of 1787 consecutive Ph-neg MPN patients seen at our institution and determined that 2% of Ph-neg MPN patients harbored an alteration involving Chr12 by cytogenetic evaluation. Retrospective chart review revealed that patients with Chr12 abnormalities had a higher likelihood of having myelofibrosis (MF) compared to patients without a Chr12 abnormality, and were more likely to have post-polycythemia vera MF. The most common alterations in Chr12 in MF patients involved 12q13, 12q15, 12q24, and trisomy 12, and >40% of Chr12 Ph-neg MPN patients had cytogenetic evolution. Chr12 abnormalities did not significantly correlate with JAK2 status, progression to acute myeloid leukemia, or survival, however patients with 12q24 abnormalities trended toward poorer outcomes.

The mutation profile of JAK2, MPL and CALR in Mexican patients with Philadelphia chromosome-negative myeloproliferative neoplasms

CONTEXT AND OBJECTIVE

By using molecular markers, it is possible to gain information on both the classification and etiopathogenesis of chronic myeloproliferative neoplasias (MPN).

METHODS

In a group of 27 Mexican mestizo patients with MPNs, we studied seven molecular markers: the BCR/ABL1 fusion gene, the JAK2 V617F mutation, the JAK2 exon 12 mutations, the MPL W515L mutation, the MPL W515K mutation, and the calreticulin (CALR) exon 9 deletion or insertion. Patients with the BCR/ABL1 fusion gene were excluded. We studied 14 patients with essential thrombocythemia (ET), eight with polycythemia vera (PV), four with primary myelofibrosis (MF), and one with undifferentiated MPN.

RESULTS

We found twelve individuals with the JAK2 V617F mutation; five of them had been clinically classified as PV, five as ET, and one as MF. One patient with the MPL W515L was identified with a clinical picture of ET. Five patients with the CALR mutation were identified, four ET and one MF. No individuals with either the MPL W515K mutation or the JAK2 exon 12 mutations were identified. The most consistent relationship was that between PV and the JAK2 V617F mutation (p=.01).

CONCLUSIONS

Despite its small size, the study shows much less prevalence of JAK2 mutation in PV, ET and MF, which does not match international data.

Role of calreticulin mutations in the aetiological diagnosis of splanchnic vein thrombosis

BACKGROUND & AIMS

Myeloproliferative neoplasms are the most common aetiological cause of splanchnic vein thrombosis (SVT). In these patients, the JAK2V617F mutation has facilitated the diagnosis of an underlying myeloproliferative neoplasm (MPN). Recently, somatic mutations of the calreticulin (CALR) gene have been identified in MPN patients lacking the JAK2 mutation. The aim of the present study was to ascertain whether CALR mutations could also play a role in the diagnosis of masked MPN in SVT.

METHODS

We included 209 patients with SVT (140 with PVT and 69 with Budd-Chiari syndrome) who had a complete aetiological diagnostic work-out. They were investigated for CALR mutations.

RESULTS

CALR mutations were found in 4 of the 209 patients (1.9%). They represented 5.4% of patients with an underlying MPN of whom all had already been diagnosed with a MPN using conventional criteria including bone marrow biopsy findings.

CONCLUSIONS

In the screening of underlying MPNs in patients with SVT, given its high frequency in these disorders, the JAK2 mutation must be evaluated first and, if negative, CALR mutations should also be investigated. This approach would increase the diagnostic yield of masked MPNs by reducing the need for additional studies.

Acquired somatic mutations of isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) in preleukemic disorders

Mutations of isocitrate dehydrogenase isoform 1 and 2 (IDH1 and IDH2) genes have been identified in glioblastoma and acute myeloid leukemia (AML). However, little is known about the molecular alterations of IDH genes in preleukemic disorders with a propensity to transform to AML. We performed polymerase chain reaction-denaturing high performance liquid chromatography (PCR-DHPLC) followed by direct sequencing to detect IDH mutations in 237 patients with myeloproliferative neoplasms (MPNs; n=108), myelodysplastic syndrome (MDS; n=22), paroxysmal nocturnal hemoglobinuria (PNH; n=41), and aplastic anemia (AA; n=66). No IDH1 R132 and IDH2 R172 mutations were identified in the entire cohort, whereas IDH1 G105G allele was detected in 4/108 MPN (3.70%), 2/22 MDS (9.09%), and 2/41 PNH (4.88%) patients. Three IDH2 R140Q mutations were found in 2/108 MPN (1.85%) and 1/22 MDS (4.54%) patients, while one IDH2 G145G allele was found in 0.92% (1/108) of MPN patients. Overall, our data suggest that IDH mutations are rare in the preleukemic disorders and may not be the major initial step in AML leukemogenesis.

The JAK2 V617F mutational status and allele burden may be related with the risk of venous thromboembolic events in patients with Philadelphia-negative myeloproliferative neoplasms

INTRODUCTION

Patients with Philadelphia-negative myeloproliferative neoplasms (Ph(-) MPNs) are at increased risk of thromboembolic and hemorrhagic complications. The aim of the study was to determine the relationship between JAK2 V617F mutational status, JAK2 V617F allele burden and the risk of vascular complications occurrence.

MATERIALS AND METHODS

Analysis was performed in a cohort of 186 patients diagnosed with polycythemia vera (53), essential thrombocythemia (114), primary myelofibrosis (11), and unclassified MPN (8). The risk of vascular complications development was analyzed in 126 JAK2 V617F-positive patients with respect to allele burden assessed with allele-specific 'real-time' quantitative polymerase chain reaction (AS RQ-PCR).

RESULTS

Overall prevalence of any vascular complications was 44.6%. Arterial thrombosis occurred in 20.4%, venous thromboembolism (VTE) in 11.3%, bleeding episodes in 24.7% of patients. Individuals harboring JAK2 V617F mutation, regardless of MPN type, were at higher risk of VTE (OR=5.15, 95%CI: 1.16-22.90, P=0.024), mainly deep vein thrombosis (DVT). JAK2 allele burden higher than 20% identified patients with 7.4-fold increased risk of VTE (95%CI: 1.6-33.7, P=0.004), but not of arterial thrombosis, neither of bleeding complications, and remained the only significant VTE risk factor in multivariate logistic regression. High allele burdens (over 50%) were strikingly associated with proximal DVT cases, but not with distal DVT.

CONCLUSIONS

The group of MPN patients with JAK2 V617F allele burden higher than 20% may benefit the most from vigilant monitoring and appropriate prophylaxis against vascular events. Inclusion of JAK2 V617F mutant allele burden in new risk stratifications seems to be justified and requires controlled prospective trials.

The detection of SRSF2 mutations in routinely processed bone marrow biopsies is useful in the diagnosis of chronic myelomonocytic leukemia

Diagnosis of chronic myelomonocytic leukemia (CMML) is based on a combination of clinical, laboratory, and morphological parameters, including persistent peripheral blood monocytosis. Recently, mutations of serine/arginine-rich splicing factor 2 (SRSF2) have been identified in 40% to 50% of CMMLs and occasionally in other myeloid disorders. In this study, we established a robust assay for the detection of SRSF2 mutations in decalcified, paraffin-embedded bone marrow (BM) biopsies and investigated its diagnostic utility. BM biopsies of 78 patients with myeloid neoplasms, including 36 CMMLs, 22 myelodysplastic syndromes (MDS), and 20 Ph- myeloproliferative neoplasms (MPN) were analyzed. The region around hot spot P95 in exon 1 of SRSF2 was amplified and bidirectionally sequenced. In addition, a restriction fragment length polymorphism analysis was established. The JAK2 V617F mutation was investigated by allele-specific polymerase chain reaction. SRSF2 mutations were identified in 16 (44%) of 36 CMMLs, including 1 of 3 cases with associated systemic mastocytosis, 4 (20%) of 20 Ph- MPN, and 1 (4.5%) of 22 MDS. Restriction fragment length polymorphism analysis detected all mutations with the exception of a single P95A. Of note, 2 cases of JAK2 V617F+ primary myelofibrosis with SRSF2 mutation initially were diagnosed as CMML based on significant peripheral blood monocytosis. In CMML, no correlation with histopathology and/or clinical parameters was observed, but SRSF2 mutations were associated with normal karyotype (P < .001). In summary, SRSF2 mutations are frequent in CMML and a useful diagnostic feature demonstrable in BM biopsies, allowing a definitive diagnosis for cases with minimal dysplasia and normal karyotype. The role of SRSF2 mutations in cases with hybrid features between primary myelofibrosis and CMML needs further investigation.

The future of JAK inhibition in myelofibrosis and beyond

The identification of aberrant JAK-STAT signaling in patients with myeloproliferative neoplasms has served as the basis for the development of a new class of targeted agents. Ruxolitinib, the first-in-class oral small molecule JAK1/2 inhibitor, has demonstrated clinical efficacy and shown a potential overall survival benefit in two randomized phase III clinical trials. However, this agent has not been associated with improvements in cytopenias, molecular remissions, or resolution of bone marrow fibrosis. Therefore, further translational research is needed to improve the understanding of the pathogenetic mechanisms driving this myeloid malignancy to ultimately address remaining unmet clinical needs. A number of novel JAK inhibitors are being evaluated in ongoing clinical trials and the full clinical potential of these newer agents remains incompletely understood. The use of JAK inhibition in combination therapy approaches, as well as mono- and combination therapies in the treatment of advanced forms of polycythemia vera are also under active investigation. This review will update the reader on the current understanding of oncogenic JAK-STAT pathway activity in the pathogenesis of myeloproliferative neoplasms and the current success and limitations of anti-JAK therapy.

The molecular landscape of childhood myeloproliferative neoplasms

The classical myeloproliferative neoplasms (MPN) are comparatively uncommon in children and display a degree of mutational naivety if considering the high frequency of known MPN driver events observed in the corresponding adult diseases. Whole exome sequencing has unravelled much of the underlying molecular complexity of MPN in adult patients yet less is known of the pathogenetic mechanisms when these diseases occur in childhood. It is proposed that such methodological approaches will contribute significant insights into the molecular landscape of childhood MPN that may in turn impact on understanding the pathophysiology of disease in their adult counterparts.

Angiogenesis in myeloproliferative neoplasms, new markers and future directions

Tumor angiogenesis has been identified to play a critical role in tumor growth and tumor progression, and is regulated by a balance of angiogenic and antiangiogenic cytokines. This has been documented for solid tumors, and there is emerging evidence suggesting that tumor progression of hematological malignancies also depends on the induction of new blood vessel formation. Data on angiogenesis in the bone marrow of BCR-ABL1-negative myeloproliferative neoplasm patients suggest an increase of the microvessel density and vascular endothelial growth factor (VEGF) expression, and there is a relation to the JAK2-V617F status. The most important proangiogenic agent is VEGF, activating VEGF receptors 1 and 2. Inhibition of VEGF signaling by monoclonal antibodies or small molecules (kinase inhibitors) has already been successfully established for the treatment of different cancer entities, and multiple new drugs are being tested in clinical trials. Most patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF) that was not associated with a JAK2 or MPL alteration carried a somatic mutation in calreticulin (CALR). Thus, CALR mutations should be included in the next classification system for ET/PMF. This review summarizes recent advances in the basic understanding of the role of angiogenesis in myeloproliferative neoplasms and the translation of such basic findings into clinical studies.

[Molecular characterization of atypical chronic myeloid leukemia and chronic neutrophilic leukemia]

BACKGROUND AND OBJECTIVE

Atypical chronic myeloid leukemia (aCML) and chronic neutrophilic leukemia (CNL) display similar clinical and hematological characteristics. The objective of the present study was to determine the mutational status of SETBP1 and CSF3R in these diseases.

PATIENTS AND METHOD

The mutational status of SETBP1 and CSF3R was studied in 7 patients with aCML (n = 3), CNL (n = 1) and unclassifiable myeloproliferative neoplasms (MPN-u) (n = 3). Additionally, mutations in ASXL1, SRSF2, IDH1/2, DNMT3A, and RUNX1 were also analyzed.

RESULTS

SETBP1 mutations (G870S and G872R) were detected in 2 patients with MPN-u, and one of them also presented mutations in SRSF2 (P95H) and ASXL1 (E635fs). The CNL case showed mutations in CSFR3 (T618I), SETBP1 (G870S) and SRSF2 (P95H). No patient classified as aCML had mutations in SETBP1 or CSF3R. One of the patients with mutations evolved to acute myeloid leukemia, while the other 2 had disease progression without transformation to overt leukemia.

CONCLUSION

The knowledge of the molecular alterations involved in these rare diseases is useful in the diagnosis and may have an impact on both prognosis and therapy.

Coexistence of JAK2V617F Mutation and BCR-ABL Translocation in a Pregnant Woman with Essential Thrombocythemia

In 2012, a 25-years-old pregnant woman presented with thromocytosis for 4 months, blood counts showed platelets 701 × 10(9)/L. Bone marrow examination disclosed a feature of hypercellular marrow in erythrocytic,granulocytic and megakaryocytic series. Cytogenetic analysis showed t(9;22)(q34;q11) in 100 % of metaphase. The percentage of BCR-ABL-positive FISH signals was 37 % in the peripheral blood. Molecular analysis showed the presence of the JAK2V617F mutation and BCR-ABL mRNA b3a2 transcript. A diagnosis of concomitant presence of essential thrombocythemia and chronic myelocytic leukemia was made. Based on this case and literatures reported before, it might be necessary to detect JAK2-V617F mutation and BCR-ABL fusion gene concomitantly in myeloproliferative neoplasms patients.

JAK/STAT pathway dysregulation in tumors: a Drosophila perspective

Sustained activation of the JAK/STAT pathway is causal to human cancers. This pathway is less complex in Drosophila, and its dysregulation has been linked to several tumor models in this organism. Here, we discuss models of metastatic epithelial and hematopoietic tumors that are causally linked to dysregulation of JAK/STAT signaling in Drosophila. First, we focus on cancer models in imaginal discs where ectopic expression of the JAK/STAT pathway ligand Unpaired downstream of distinct tumor suppressors has emerged as an unexpected mediator of neoplastic transformation. We also discuss the collaboration between STAT and oncogenic Ras in epithelial transformation. Second, we examine hematopoietic tumors, where mutations that cause hyperactive JAK/STAT signaling are necessary and sufficient for "fly leukemia". We highlight the important contributions that genetic screens in Drosophila have made to understanding the JAK/STAT pathway, its developmental roles, and how its function is co-opted during tumorigenesis.

Effect of chemical modification on the ability of pyrrolidinium fullerene to induce apoptosis of cells transformed by JAK2 V617F mutant

JAK2 V617F mutant, a gene responsible for human myeloproliferative neoplasms (MPNs), causes not only cellular transformation but also resistance to various anti-cancer drugs. We previously reported that pyrrolidinium fullerene markedly induced the apoptosis of JAK2 V617F mutant-induced transformed cells through the reduction of apoptosis signal-regulating kinase 1 (ASK1), following inhibition of the c-Jun N-terminal kinase (JNK) pathway. In the current study, we found that the replacement of the 2-hydrogen atom (H) or N-methyl group (CH3) by the butyl group (C4C9) caused the more than 3-fold potent cytotoxic effects on cells transformed by the JAK2 V617F mutant. Strikingly, these chemical modification of pyrrolidinium fullerene resulted in more marked reduction of ASK1 protein and a more potent inhibitory effect on the JNK signaling cascade. On the other hand, when modified with a longer alkyl group, the derivatives lacked their cytotoxicity. These observations clearly indicate that the modification of pyrrolidinium fullerene with a suitable length of alkyl group such as butyl group enhances its apoptotic effect through inhibition of the ASK1-MKK4/7-JNK pathway.

Chronic kidney disease in patients with the Philadelphia-negative chronic myeloproliferative neoplasms

BACKGROUND

The progression of kidney function and frequency of chronic kidney disease (CKD) in patients with the Philadelphia-negative myeloproliferative neoplasms (MPN) is unknown, although CKD is linked to increased mortality.

METHODS

This longitudinal retrospective study evaluates the estimated glomerular filtration rate (eGFR) in 143 MPN patients over a period of 9 years.

RESULTS

29% of patients had CKD stage 3 or 4 at time of diagnosis. 20% of patients had a rapid annual loss of eGFR (>3mL/min/1.73m(2)) and eGFR was negatively correlated to monocyte and neutrophil counts.

CONCLUSION

Kidney impairment might contribute to the increased mortality observed in MPN patients.

The Differential Diagnosis of Eosinophilia in Neoplastic Hematopathology

Eosinophilia in the peripheral blood is classified as primary (clonal) hematologic neoplasms or secondary (nonclonal) disorders, associated with hematologic or nonhematologic disorders. This review focuses on the categories of hematolymphoid neoplasms recognized by the 2008 World Health Organization Classification of Tumours and Haematopoietic and Lymphoid Tissues that are characteristically associated with eosinophilia. We provide a systematic approach to the diagnosis of these neoplastic proliferations via morphologic, immunophenotypic, and molecular-based methodologies, and provide the clinical settings in which these hematolymphoid neoplasms occur. We discuss recommendations that eosinophilia working groups have published addressing some of the limitations of the current classification scheme.

A role of NF-E2 in chronic inflammation and clonal evolution in essential thrombocythemia, polycythemia vera and myelofibrosis?

A novel murine model for myeloproliferative neoplasms (MPNs) generated by overexpression of the transcription factor NF-E2 has recently been described. Sustained overexpression of NF-E2 in this model induced myeloid expansion with anemia, leukocytosis and thrombocytosis. Herein, it is debated if NF-E2 overexpression also might have induced a sustained state of in vivo leukocyte and platelet activation with chronic and self-perpetuating production of inflammatory products from activated leukocytes and platelets. If so, this novel murine model also may excellently describe the deleterious impact of sustained chronic NF-E2 overexpression during uncontrolled chronic inflammation upon the hematopoietic system--the development of clonal myeloproliferation. Accordingly, this novel murine model may also have delivered the proof of concept of chronic inflammation as a trigger and driver of clonal evolution in MPNs.