JAK2 mutation 1849G>T is rare in acute leukemias but can be found in CMML, Philadelphia chromosome-negative CML, and megakaryocytic leukemia

A 27-Year-Old Female With JAK2 Mutation: A Case of Budd-Chiari Syndrome Secondary to Prolonged Oral Contraceptive Pill Use

Individuals with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) such as polycythemia vera and essential thrombocythemia (ET) demonstrate an increased thrombotic risk associated with JAK2 mutations. Physicians must take heed when treating these patients, to mitigate this pro-thrombotic state as much as possible. Failure to do so, or exacerbating the state, can lead to dire consequences. We present the case of a 27-year-old female with a history of ulcerative colitis (UC) and ET, currently taking estrogen-containing oral contraceptive pills (OCPs). She presented to the emergency department with rapid weight gain, jaundice, nausea, and diarrhea and was found to have obstructive jaundice and thrombotic burden that extended into the portal, mesenteric, splenic, and hepatic veins. On the second attempt, a successful transjugular intrahepatic portosystemic shunt procedure was performed, resulting in improved venous flow. This case underscores the importance of cautious medication use, especially OCPs, in patients with hypercoagulable states due to JAK2 mutations, for example, the V617F mutation in JAK2. It emphasizes the need for vigilant monitoring, individualized management, and a multidisciplinary approach to mitigate thrombotic complications. Increased awareness and continued research are crucial for optimizing treatment strategies for patients with MPNs and associated genetic mutations.

Modulation of human thrombopoietin receptor conformations uncouples JAK2 V617F-driven activation from cytokine-induced stimulation

The thrombopoietin receptor (TpoR) plays a central role in myeloproliferative neoplasms (MPNs). Mutations in JAK2, calreticulin, or TpoR itself drive the constitutive activation of TpoR and uncontrolled proliferation and differentiation of hematopoietic stem cells and progenitors. The JAK2 V617F mutation is responsible for most MPNs, and all driver mutants induce pathologic TpoR activation. Existing therapeutic strategies have focused on JAK2 kinase inhibitors that are unable to differentiate between the mutated MPN clone and healthy cells. Surprisingly, the targeting of TpoR itself has remained poorly explored despite its central role in pathology. Here, we performed a comprehensive characterization of human TpoR activation under physiological and pathological conditions, focusing on the JAK2 V617F mutant. Using a system of controlled dimerization of the transmembrane and cytosolic domains of TpoR, we discovered that human TpoR (hTpoR) adopts different dimeric conformations upon Tpo-induced vs JAK2 V617F-mediated activation. We identified the amino acids and specific dimeric conformation of hTpoR responsible for activation in complex with JAK2 V617F and confirmed our findings in the full-length receptor context in hematopoietic cell lines and primary bone marrow cells. Remarkably, we found that the modulation of hTpoR conformations by point mutations allowed for specific inhibition of JAK2 V617F-driven activation without affecting Tpo-induced signaling. Our results demonstrate that modulation of the hTpoR conformation is a viable therapeutic strategy for JAK2 V617F-positive MPNs and set the path for novel drug development by identifying precise residues of hTpoR involved in JAK2 V617F-specific activation.

Clonal haematopoiesis - a novel entity that modifies pathological processes in elderly

Progress in the development of new sequencing techniques with wider accessibility and higher sensitivity of the protocol of deciphering genome particularities led to the discovery of a new phenomenon - clonal haematopoiesis. It is characterized by the presence in the bloodstream of elderly people a minor clonal population of cells with mutations in certain genes, but without any sign of disease related to the hematopoietic system. Here we will review this recent advancement in the field of clonal haematopoiesis and how it may affect the disease's development in old age.

Molecular Studies for the Early Detection of Philadelphia-Negative Myeloproliferative Neoplasms

JAK2 V617F is the predominant driver mutation in patients with Philadelphia-negative myeloproliferative neoplasms (MPN). JAK2 mutations are also frequent in clonal hematopoiesis of indeterminate potential (CHIP) in otherwise "healthy" individuals. However, the period between mutation acquisition and MPN diagnosis (known as latency) varies widely between individuals, with JAK2 mutations detectable several decades before diagnosis and even from birth in some individuals. Here, we will review the current evidence on the biological factors, such as additional mutations and chronic inflammation, which influence clonal expansion and may determine why some JAK2-mutated individuals will progress to an overt neoplasm during their lifetime while others will not. We will also introduce several germline variants that predispose individuals to CHIP (as well as MPN) identified from genome-wide association studies. Finally, we will explore possible mutation screening or interventions that could help to minimize MPN-associated cardiovascular complications or even delay malignant progression.

Clinical characteristics of a patient with de novo acute promyelocytic leukemia with JAK2 v617f mutation

BACKGROUND

The V617F mutation of Janus-associated kinase 2 (JAK2) is common in myeloproliferative neoplasms (MPN). JAK2 V617F mutation can be detected in patients with de novo acute myeloid leukemia (AML), but de novo acute promyelocytic leukemia (APL) with JAK2 V617F mutation is rare.

CASE PRESENTATION

We report a case of APL with both the t(15;17) translocation as well as the JAK2 V617F mutation that transformed into MPN (PV/ET).

CONCLUSIONS

A de novo APL patient presented initially with JAK2 V617F. After ATRA and ATO dual induction and chemotherapy consolidation, the patient achieved complete remission (CR) with undetectable PML/RARα. However, the JAK2 V617F remained positive, and the patient developed MPN (PV/ET) 22 months later, which responded well to interferon therapy.AML, acute myeloid leukemia; APL, acute promyelocytic leukemia; ATRA, all-trans retinoic acid; ATO, arsenic trioxide; BM, bone marrow; CR, complete remission; ET, essential thrombocythemia; Hb, hemoglobin; JAK2, Janus-associated kinase 2; MPN, myeloproliferative neoplasms; PLT, platelets; PMF, primary myelofibrosis; PML/RARα; PV, polycythemia vera; WBC, white blood cells.

JAK2 V617f in chronic myeloid leukemia: driving force or passive bystander?

OBJECTIVES

BCR-ABL1 and JAK2 V617F coexistence in myeloproliferative neoplasms has been described as concomitant or sequential events. Despite this, we present a unique case of chronic myeloid leukemia (CML) not referable to either of the known scenarios.

METHODS

BCR-ABL1 molecular monitoring was performed by real-time quantitative PCR (RQ-PCR). At the time of molecular relapse, a targeted next-generation sequencing analysis with a customized panel of 26 genes commonly mutated in myeloid diseases was performed. To investigate the kinetics of the JAK2 variant and its association with the BCR-ABL1 rearrangement, RQ-PCR was performed at different time points during the patient's follow-up.

RESULTS

While negative at CML diagnosis, the JAK2 mutation was first detected 9 years later (VAF: 7.2%). The mutational burden of JAK2 remained stable in multiple determinations, with minor fluctuations independent of BCR-ABL1 kinetics. At the last available time point, the patient was in deep molecular response (MR4), the JAK2 mutational burden was 7%, and no clinical-laboratory findings of Ph-MPN were detectable.

DISCUSSION

In the presented case, the JAK2variantoccurring during the course of the disease seems to stay in the shadows of CML, just as a bystander. The impact of this event (that may be considered suggestive of clonal hematopoiesis of indeterminate potential) on the disease outcome, even if seemingly irrelevant, has still to be explored.

Pediatric non–Down’s syndrome acute megakaryoblastic leukemia patients in China: A single center's real-world analysis

Non-Down’s syndrome acute megakaryocytic leukemia (non-DS-AMKL) is a subtype of childhood acute myeloid leukemia (AML), whose prognosis, prognostic factors and treatment recommendations have not yet to be defined in children. We conducted a retrospective study with 65 newly diagnosed non-DS-AMKL children from August 2003 to June 2020 to investigate the clinical impact of factors and clinical outcome. Among all 65 patients, 47 of them were treated at our center who received three different regimens due to time point of admission (CAMS-another, CAMS-2009 and CAMS-2016 protocol), and the efficacy were compared. Patients with newly diagnosed non-DS-AMKL accounted for 7.4% of pediatric AML cases. The median age of the patients was 18 months at diagnosis, and over 90% of them were under three-years-old. The overall survival (OS) rates were 33.3% ± 1.7%, 66.7% ± 24.4% and 74.2% ± 4.0% for three groups (CAMS-another, CAMS-2009 and CAMS-2016 regimen), respectively. In CAMS-2016 group, the complete remission (CR) rate after induction was 67.7% (21/31), while the total CR rate after all phases of chemotherapy was 80.6% (25/31). The 2-year survival probability did not significantly improve in patients underwent HSCT when compared with non-HSCT group (75.0% ± 4.7% vs. 73.9% ± 4.6%, p=0.680). Those who had a “dry tap” during BM aspiration at admission had significantly worse OS than those without “dry tap” (33.3% ± 8.6% vs. 84.0% ± 3.6%, p=0.006). Moreover, the results also revealed that patients with CD34+ had significantly lower OS (50.0% ± 6.7% vs. 89.5% ± 3.5%, p=0.021), whereas patients with CD36+ had significantly higher OS than those who were negative (85.0% ± 4.0% vs. 54.5% ± 6.6%, p=0.048). In conclusion, intensive chemotherapy resulted in improved prognosis of non-DS-AMKL children and subclassification may base on “dry tap” and immunophenotypic. Although some progress has been made, outcomes of non-DS-AMKL children remain unsatisfactory, especially in HSCT group, when compared with other AML types.

Targeted sequencing of candidate gene regions for myelofibrosis in dogs

Background

Myelofibrosis often lacks an identifiable cause in dogs. In humans, most primary myelofibrosis cases develop secondary to driver mutations in JAK2, CALR, or MPL.

Objectives

To determine the prevalence of variants in JAK2, CALR, or MPL candidate regions in dogs with myelofibrosis and in healthy dogs.

Animals

Twenty‐six dogs with myelofibrosis that underwent bone marrow biopsy between 2010 and 2018 and 25 control dogs matched for age, sex, and breed.

Methods

Cross‐sectional study. Amplicon sequencing of JAK2 exons 12 and 14, CALR exon 9, and MPL exon 10 was performed on formalin‐fixed, decalcified, paraffin‐embedded bone marrow (myelofibrosis) or peripheral blood (control) DNA. Somatic variants were categorized as likely‐benign or possibly‐pathogenic based on predicted impact on protein function. Within the myelofibrosis group, hematologic variables and survival were compared by variant status (none, likely‐benign only, and ≥1 possibly‐pathogenic). The effect of age on variant count was analyzed using linear regression.

Results

Eighteen of 26 (69%) myelofibrosis cases had somatic variants, including 9 classified as possibly‐pathogenic. No somatic variants were detected in controls. Within the myelofibrosis group, hematologic variables and survival did not differ by variant status. The number of somatic variants per myelofibrosis case increased with age (estimate, 0.69; SE, 0.29; P = .03).

Conclusions and Clinical Importance

Somatic variants might initiate or perpetuate myelofibrosis in dogs. Our findings suggest the occurrence of clonal hematopoiesis in dogs, with increasing incidence with age, as observed in humans.

Silica-Coated Iron Oxide Nanoparticles for DNA Isolation for Molecular Genetic Studies in Hematology

Aim: To develop magnetic nanoparticles (MNPs) based on iron oxide for DNA isolation from blood cells for quantitative molecular genetic analyses of the V617F mutation in the Januskinase 2 (JAK2) gene. Materials and Methods: MNPs were synthesized by the coprecipitation method and coated with tetraethyl orthosilicate (TEOS). The size and shape of the complexes were estimated using transmission electron microscopy. Twenty blood samples from patients with myeloproliferative disorders were used for DNA isolation with the MNPs. DNA quality and compatibility for molecular genetic studies of the JAK2 V617F mutation were investigated by gel electrophoresis and real-time polymerase chain reaction (RT-PCR). Results: The average amount of DNA isolated from 150 μL of whole blood was 75.2 ng when MNPs were used and 72.5 ng when standard silica sorbent was used. There was no DNA damage observed after interaction with MNPs. RT-PCR demonstrated similar values for the JAK2 V617F mutant DNA ratios in the samples after DNA isolation with MNPs and by standard sorption on silica. Conclusions: MNPs with silicate capsules of sufficient thickness were obtained and the undesirable damaging effect of iron oxides on nucleic acids during isolation from cells were eliminated. Designed MNPs allow obtaining intact DNA for molecular genetic studies using the example of the JAK2 V617F for study.

Recent Advances in the Use of Molecular Analyses to Inform the Diagnosis and Prognosis of Patients with Polycythaemia Vera

Genetic studies in the past decade have improved our understanding of the molecular basis of the BCR-ABL1-negative myeloproliferative neoplasm (MPN) polycythaemia vera (PV). Such breakthroughs include the discovery of the JAK2V617F driver mutation in approximately 95% of patients with PV, as well as some very rare cases of familial hereditary MPN caused by inherited germline mutations. Patients with PV often progress to fibrosis or acute myeloid leukaemia, both associated with very poor clinical outcome. Moreover, thrombosis and major bleeding are the principal causes of morbidity and mortality. As a result of increasingly available and economical next-generation sequencing technologies, mutational studies have revealed the prognostic relevance of a few somatic mutations in terms of thrombotic risk and risk of transformation, helping to improve the risk stratification of patients with PV. Finally, knowledge of the molecular basis of PV has helped identify targets for directed therapy. The constitutive activation of the tyrosine kinase JAK2 is targeted by ruxolitinib, a JAK1/JAK2 tyrosine kinase inhibitor for PV patients who are resistant or intolerant to cytoreductive treatment with hydroxyurea. Other molecular mechanisms have also been revealed, and numerous agents are in various stages of development. Here, we will provide an update of the recent published literature on how molecular testing can improve the diagnosis and prognosis of patients with PV and present recent advances that may have prognostic value in the near future.

A Case Report of BCR-ABL-JAK2-Positive Chronic Myeloid Leukemia with Complete Hematological and Major Molecular Response to Dasatinib

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm (MPN) that harbors the Philadelphia chromosomal translocation resulting in the uncontrolled production of mature granulocytes. Commonly, patients are diagnosed with CML during blood work for other reasons or enlarged spleen. The diagnosis is based on WHO criteria that require the demonstration of Philadelphia chromosome. Typically, JAK2 mutation is not found in BCR-ABL1-positive MPN (CML). Most patients with CML are JAK2 negative. It is rare for CML Philadelphia-positive patients to have a coexisting JAK2 mutation. Little is known regarding the effect of JAK2 mutation on the disease course of CML, the complications, and the response to treatment. We report the case of a 57-year-old man with no previous medical illness who presented with elevated white blood cell count on perioperative assessment for hernial repair; on further workup, he was diagnosed with Philadelphia-positive CML. He was found to have JAK2 mutation and was started on treatment with dasatinib and achieved hematological and cytogenetic remission with loss of the JAK2 mutation. Patients with JAK2-positive BCR-ABL-positive CML had a good hematological and cytogenetic response to dasatinib. In such rare coexistence of JAK and BCR-ABL, dasatinib is a good option due to multi-kinase activity.

MRTFA: A critical protein in normal and malignant hematopoiesis and beyond

Myocardin-related transcription factor A (MRTFA) is a coactivator of serum response factor, a transcription factor that participates in several critical cellular functions including cell growth and apoptosis. MRTFA couples transcriptional regulation to actin cytoskeleton dynamics, and the transcriptional targets of the MRTFA–serum response factor complex include genes encoding cytoskeletal proteins as well as immediate early genes. Previous work has shown that MRTFA promotes the differentiation of many cell types, including various types of muscle cells and hematopoietic cells, and MRTFA's interactions with other protein partners broaden its cellular roles. However, despite being first identified as part of the recurrent t(1;22) chromosomal translocation in acute megakaryoblastic leukemia, the mechanisms by which MRTFA functions in malignant hematopoiesis have yet to be defined. In this review, we provide an in-depth examination of the structure, regulation, and known functions of MRTFA with a focus on hematopoiesis. We conclude by identifying areas of study that merit further investigation.

Successful Treatment of a Patient with Chronic Myelogenous Leukemia with Concurrent Janus Kinase 2 (JAK2) R795S Mutation and Breakpoint Cluster Region-ABL1 (BCR-ABL1) Fusion: A Case Report and Literature Review

Patient: Female, 50-year-old

Final Diagnosis: Chronic myeloid leukaemia

Symptoms: Dizziness • weakness

Medication: —

Clinical Procedure: —

Specialty: Hematology

Co-existence of mutations in myeloproliferative neoplasms and their clinical significance: a prognostic approach

OBJECTIVE

Myeloproliferative neoplasms (MPNs) are a group of clonal hematopoietic stem cell disorders that may occur after one or more mutations in hematopoietic progenitor cells. In this study, we will review the co-existence of mutations (especially dual mutations) in MPNs and its effect on the prognosis of patients.

METHODS

To find relevant published papers, we systematically searched six major international indexing databases, namely PubMed/Medline, EmBase, Cochrane central, ISI web of science, and Scopus from Feb. 2000 until Jan. 2020. We included the following keywords in the analyzes: Myeloproliferative Disorders, Mutation, Co-existence of Mutations, Acute myeloid leukemia.

RESULTS

Co-existence of several mutations in MPNs is mainly associated with a poor prognosis compared with the unimutated MPN disorders. There are several effective factors such as sequence of mutations, incidence of mutations in one cell or different cells, mutation, and MPN type.

CONCLUSION AND EXPERT COMMENTARY

It seems that monitoring the status of mutations in MPNs and recognizing the co-existence of mutations (especially dual mutations) in order to determine prognosis and possibility of progression to acute form of leukemia can lead to the prediction of prognosis in MPN patients as well as establishment of better and more reliable therapeutic strategies for patients.

A rare atypical chronic myeloid leukemia BCR-ABL1 negative with concomitant JAK2 V617F and SETBP1 mutations: a case report and literature review

Atypical chronic myeloid leukemia (aCML) BCR-ABL1 negative is a rare myelodysplastic syndromes/myeloproliferative neoplasm (MDS/MPN) for which no standard treatment currently exists. The advent of next-generation sequencing has allowed our understanding of the molecular pathogenesis of aCML to be expanded and has made it possible for clinicians to more accurately differentiate aCML from similar MDS/MPN overlap syndrome and MPN counterparts, as MPN-associated driver mutations in JAK2, CALR, or MPL are typically absent in aCML. A 55-year old male with main complaints of weight loss and fatigue for more than half a year and night sweats for more than 2 months was admitted to our hospital. Further examination revealed increased white blood cells, splenomegaly, and grade 1 bone marrow fibrosis with JAK2 V617F, which supported a preliminary diagnosis of pre-primary marrow fibrosis. However, in addition to JAK2 V617F (51.00%), next-generation sequencing also detected SETBP1 D868N (46.00%), ASXL1 G645fs (36.09%), and SRSF2 P95_R102del (33.56%) mutations. According to the 2016 World Health Organization diagnostic criteria, the patient was ultimately diagnosed with rare aCML with concomitant JAK2 V617F and SETBP1 mutations. The patient received targeted therapy of ruxolitinib for 5 months and subsequently an additional four courses of combined hypomethylating therapy. The patient exhibited an optimal response, with decreased spleen volume by approximately 35% after therapy and improved symptom scores after therapy. In diagnosing primary bone marrow fibrosis, attention should be paid to the identification of MDS/MPN. In addition to basic cell morphology, mutational analysis using next-generation sequencing plays an increasingly important role in the differential diagnosis. aCML with concomitant JAK2 V617F and SETBP1 mutations has been rarely reported, and targeted therapy for mutated JAK2 may benefit patients, especially those not suitable recipients of hematopoietic stem cell transplants.

Emergence of BCR-ABL1 Chronic Myeloid Leukemia in a JAK2-V617F Polycythemia Vera

Emergence of a new chronic myeloid neoplasm in the setting of a previous one, or their concomitant appearance seems to be a rare event, but plenty of cases have been reported. We describe the case of a patient with JAK2-V617F polycythemia vera, which looses JAK2 clone and develops overt BCR-ABL1 chronic myeloid leukemia after 6 years. Once treatment with tyrosine kinase inhibitors controls BCR-ABL1 clone, JAK2 clone arises again. In this report, we review the literature and discuss the clonal relationship of this event in light of the new molecular data.

JAK2-negative acute monocytic leukemia with TET2 mutation in essential thrombocythemia with JAK2 mutation with literature review

Essential thrombocythemia (ET) is an indolent myeloproliferative neoplasm (MPN) with a transformation to acute myeloid leukemia in <5% of patients. A 79-year-old man with JAK2V617F-positive ET exhibited leukocytosis with an increase in monoblastic cells, leading to a diagnosis of acute monoblastic and monocytic leukemia. Leukemic cells carried a TET2 mutation but not JAK2V617F mutation. We concluded that the TET2 mutation occurred in MPN-initiating cells and overcame JAK2-mutated cells. The absence of a JAK2 mutation in the leukemic cells in this case suggests the leukemia emerged from a JAK2-negative MPN cell clone carrying the TET2 mutation.

Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling

The Janus kinase-signal transducer and activator of transcription protein (JAK-STAT) pathway mediates essential biological functions from immune responses to haematopoiesis. Deregulated JAK-STAT signaling causes myeloproliferative neoplasms, leukaemia, and lymphomas, as well as autoimmune diseases. Thereby JAKs have gained significant relevance as therapeutic targets. However, there is still a clinical need for better JAK inhibitors and novel strategies targeting regions outside the conserved kinase domain have gained interest. In-depth knowledge about the molecular details of JAK activation is required. For example, whether the function and regulation between receptors is conserved remains an open question. We used JAK-deficient cell-lines and structure-based mutagenesis to study the function of JAK1 and its pseudokinase domain (JH2) in cytokine signaling pathways that employ JAK1 with different JAK heterodimerization partner. In interleukin-2 (IL-2)-induced STAT5 activation JAK1 was dominant over JAK3 but in interferon-γ (IFNγ) and interferon-α (IFNα) signaling both JAK1 and heteromeric partner JAK2 or TYK2 were both indispensable for STAT1 activation. Moreover, IL-2 signaling was strictly dependent on both JAK1 JH1 and JH2 but in IFNγ signaling JAK1 JH2 rather than kinase activity was required for STAT1 activation. To investigate the regulatory function, we focused on two allosteric regions in JAK1 JH2, the ATP-binding pocket and the αC-helix. Mutating L633 at the αC reduced basal and cytokine induced activation of STAT in both JAK1 wild-type (WT) and constitutively activated mutant backgrounds. Moreover, biochemical characterization and comparison of JH2s let us depict differences in the JH2 ATP-binding and strengthen the hypothesis that de-stabilization of the domain disturbs the regulatory JH1-JH2 interaction. Collectively, our results bring mechanistic understanding about the function of JAK1 in different receptor complexes that likely have relevance for the design of specific JAK modulators.

Atypical CML- the role of morphology and precision genomics

Atypical chronic myeloid leukemia is an esoteric myeloid malignancy with features of both myeloproliferative and myelodysplastic syndromes. This disease is characterized primarily by morphologic-based criteria, and has clinical and molecular features overlapping with other myeloid malignancies. No one molecular abnormality is specific, and multiple mutations are often present in various combinations, due to the malignant multi-step clonal evolution of myeloid malignancies. In this review, we will address what we know about atypical chronic myeloid leukemia; evaluate how the molecular landscape in myeloid malignancies overlaps, and discuss what we can learn by incorporating individualized precision genomic strategies.

JAK2 and Beyond: Mutational Study of JAK2V617 in Myeloproliferative Disorders and Haematological Malignancies in Kashmiri population

BACKGROUND

Janus Tyrosine Kinase-2 (JAK2 V617F), a novel point mutation affecting the MPD'S is a somatic gain-of-function mutation. It alters a highly conserved amino acid valine in the negative regulatory JH2 domain to phenylalanine predicted to dysregulate kinase activity.

AIM

To evaluate the prevalence and clinical significance of JAK2 V617F mutation in various MPD's as well as in hematological malignancies.

SUBJECTS AND METHODS

JAK2 mutation was assessed in 90 patients with myeloproliferative disorders and 47 leukemic patients. In addition, peripheral blood samples from 90 healthy donors were also collected as control. We used a highly sensitive Allele-Specific polymerase chain reaction (AS-PCR) for the detection and confirmed the mutation further by direct sequencing.

RESULTS

Our results showed significant differences between various disorders with respect to either the proportion of positivity or that of mutant alleles. JAK2-V617F was detected in 67/90 MPD patients and 02/17 for AML,01/11 for ALL-L1,02/12 for ALL-L2 and 02/07 for CML and 90 healthy controls.

CONCLUSION

From the above findings it is evident that the JAK2 V617F mutation is widespread not only in MPD's but also in hematological malignancies, which might as well lead to the new classification of MPD'S. Our data also suggest that different genetic events may lead to JAK-STAT pathway activation in different malignancies.

Molecular Mechanisms of Epigenetic Regulators as Activatable Targets in Cancer Theranostics

Epigenetics is defined as somatically inheritable changes that are not accompanied by alterations in DNA sequence. Epigenetics encompasses DNA methylation, covalent histone modifications, non-coding RNA as well as nucleosome remodeling. Notably, abnormal epigenetic changes play a critical role in cancer development including malignant transformation, metastasis, prognosis, drug resistance and tumor recurrence, which can provide effective targets for cancer prognosis, diagnosis and therapy. Understanding these changes provide effective means for cancer diagnosis and druggable targets for better clinical applications. Histone modifications and related enzymes have been found to correlate well with cancer incidence and prognosis in recent years. Dysregulated expression or mutation of histone modification enzymes and histone modification status abnormalities have been considered to play essential roles in tumorigenesis and clinical outcomes of cancer treatment. Some of the histone modification inhibitors have been extensively employed in clinical practice and many others are still under laboratory research or pre-clinical assessment. Here we summarize the important roles of epigenetics, especially histone modifications in cancer diagnostics and therapeutics, and also discuss the developmental implications of activatable epigenetic targets in cancer theranostics.

Systematization of analytical studies of polycythemia vera, essential thrombocythemia and primary myelofibrosis, and a meta-analysis of the frequency of JAK2, CALR and MPL mutations: 2000-2018

BACKGROUND

Research into Philadelphia-negative chronic myeloproliferative neoplasms is heterogeneous. In addition, no systematization of studies of polycythemia vera (PV), essential thrombocythemia (ET) or primary myelofibrosis (PMF) have been carried out. The objective of this review is to characterize studies on BCR-ABL1-negative chronic myeloproliferative neoplasms and to compare the frequency of JAK2, MPL and CALR mutations in PV, ET and PMF.

METHOD

A systematic review of the scientific literature was conducted, as was meta-analysis with an ex-ante selection of protocol, according to phases of the PRISMA guide in three interdisciplinary databases. To guarantee reproducibility in the pursuit and retrieval of information, the reproducibility and methodological quality of the studies were evaluated by two researchers.

RESULTS

Fifty-two studies were included, the majority having been carried out in the United States, China, Brazil and Europe. The frequency of the JAK2V617F mutation ranged from 46.7 to 100% in patients with PV, from 31.3 to 72.1% in patients with ET, and from 25.0 to 85.7% in those with PMF. The frequency of the MPL mutation was 0% in PV, from 0.9 to 12.5% in ET, and from 0 to 17.1% in PMF. The CALR mutation occurred at a frequency of 0.0% in PV, whereas in ET, it ranged from 12.6 to 50%, and in PMF, it ranged from 10 to 100%. The risk of this mutation presenting in PV is 3.0 times that found for ET and 4.0 times that found for PMF.

CONCLUSION

Given the specificity and reported high frequencies of the JAK2V617F, MPL and CALR mutations in this group of neoplasms, the diagnosis of these diseases should not be made on clinical and hematological characteristics alone but should include genetic screening of patients.

Development of a high resolution melting analysis assay for rapid identification of JAK2 V617F missense mutation and its validation

Background

Myeloproliferative neoplasms (MPN) are heterogeneous diseases that classified by the presence of Philadelphia chromosome into Philadelphia chromosome negative (Ph-neg) and positive (Ph-pos) myeloproliferative neoplasms. In ph-neg group A somatic point mutation (c.1849G>T) in the JAK2 gene, part of the JAK2-STAT signal-transduction pathway, causes substitution of phenylalanine for valine (V617F) in the JAK2 protein and has been identified. This mutation was seen in PV by 65% to 97% and ET (30-57%) and primary myelofibrosis (35-95%). Highly sensitive methods have been used to determine the presence of the JAK2V617F mutation instead of direct sequencing. We aimed to assess JAK2 exon14 mutations by high-resolution melting (HRM) analysis, which allows variation screening in compare to other method for detecting mutation.

Methods

The mutation analysis included 45 individuals who were subjected for diagnosis of ph-neg MPN. Genomic DNA was isolated and different methods are performed.

Results

PCR RFLP, ARMS PCR and HRM method has a detection sensitivity comparable with conventional methods (Qiagen) to identify the mutations and sequencing.

Conclusions

For HRM analysis is cost-effective and beside that it is enzyme independence method also this method able to show amount of the mutant allele carried in samples and it's helpful for treatments follow-up and determining MRD for them.

The changing scenario of non-Down syndrome acute megakaryoblastic leukemia in children

Pediatric non-Down-syndrome acute megakaryoblastic leukemia (non-DS-AMKL) is a heterogeneous subtype of leukemia that has historically been associated with poor prognosis. Until the advent of large-scale genomic sequencing, the management of patients with non-DS-AMKL was very difficult due to the absence of reliable biological prognostic markers. The sequencing of large cohort of pediatric non-DS-AMKL samples led to the discovery of novel genetic aberrations, including high-frequency fusions, such as CBFA2T3-GLIS2 and NUP98-KDM5 A, as well as less frequent aberrations, such as HOX rearrangements. These new insights into the genetic landscape of pediatric non-DS-AMKL has allowed refining the risk-group stratification, leading to important changes in the prognostic scenario of these patients. This review summarizes the most important molecular pathogenic mechanisms of pediatric non-DS-AMKL. A critical discussion on how novel genetic abnormalities have refined the risk profile assessment and changed the management of these patients in clinical practice is also provided.

Utility of JAK2 V617F allelic burden in distinguishing chronic myelomonocytic Leukemia from Primary myelofibrosis with monocytosis

The concurrent presence of JAK2 V617F, monocytosis, and bone marrow fibrosis can be observed in both chronic myelomonocytic leukemia (CMML) and primary myelofibrosis (PMF). It can be challenging to distinguish CMML with JAK2 mutation and fibrosis from other myeloid neoplasms, particularly PMF. To identify key features that may help distinguish these 2 entities, we retrospectively studied 21 cases diagnosed as "CMML" with JAK2 V617F and bone marrow fibrosis that were identified from a cohort of 610 cases of CMML diagnosed in 2006 to 2016. Upon further review, we confirmed the diagnosis of CMML in 7 cases, 11 cases were reclassified as PMF, and 3 cases had features intermediate between CMML and PMF (gray zone). These 11 cases of PMF with monocytosis featured a higher JAK2 V617F allelic burden (median, 43%; range, 20%-62%) and atypical pleomorphic megakaryocytes with hyperchromatic nuclei. Complete blood count showed more pronounced myeloid left shift. In contrast, 7 CMML cases had significantly lower JAK2 V617F allelic burden (median, 17%; range, 5%-36%; P < .0001) and dysplastic megakaryocytes along with variable degree of dysplasia in other lineages. The median survival of PMF and CMML patients was 32 and 40 months, respectively. We conclude that besides morphology of megakaryocytes and other features, JAK2 V617F allelic burden can help differentiate CMML from PMF with monocytosis. SRSF2 and RAS mutations are observed in both disease categories. Rare gray-zone cases exist with hybrid features.

Chronic myeloid leukemia with complex karyotypes: Prognosis and therapeutic approaches

OBJECTIVE AND BACKGROUND

Chronic myeloid leukemia (CML) is a neoplastic disease whose genetic and cytogenetic changes play important roles in prognosis and treatment strategies. Philadelphia (Ph) translocation t(9;22)(q34;q11) is a diagnostic and prognostic biomarker in CML.

METHODS

Pubmed and Google Scholar databases were searched for English language articles from 1975 to 2017 containing the terms CML; Additional chromosomal abnormalities; Philadelphia translocation; Prognosis; and Treatment.

DISCUSSION

Approximately 10-12% of CML patients exhibit additional chromosomal aberrations (ACAs) in chronic phase and blast crisis. ACAs emergence may cause different features in CML patients according to Ph pattern. For instance, deletion of chromosome 9 derivation is associated to patient's bad survival, whereas monosomy 7 develops myeloid dysplastic syndrome (MDS) or acute myeloid leukemia (AML) in CML patients with Ph-negative pattern. And ACAs in Ph-positive CML is considered as a failure in the management of CML with imatinib.

CONCLUSION

CML classification using different features such as Ph and ACAs can play a decisive role in the evaluation of treatment responses in patients, for example, CML patients with Ph negative and monosomy 7 develop MDS or CML patient -Y and extra copy of Ph have a good response to tyrosine kinase inhibitors, therefore, classifications according to Ph and ACAs play an important role in choosing better treatment protocols and therapeutic strategies. Karyotype analysis in CML patients with complex karyotype shows unrandom pattern so ACAs can be great clue in medical guidelines.

Essential thrombocythemia during treatment of acute myeloid leukemia with JAK2 V617F mutation: A case report of a CARE-compliant article

RATIONALE

The JAK2 V617F mutation is frequently found in ET, while it is rare in de novo AML. ET has a low frequency of leukemic transformation. Both secondary AML (sAML) from ET and AML with JAK2 V617F mutation have poor prognoses. Because of the low incidence of JAK2 mutation in acute myeloid leukemia (AML), the clinical features of AML with JAK2 mutation are rarely reported so far, either transformed from essential thrombocythemia (ET) or de novo AML.

PATIENT CONCERNS

In this article, we present a pediatric AML patient with the JAK2 V617F mutation.

DIAGNOSES

A diagnosis of acute megakaryoblastic leukemia was made and sAML was ruled out.

INTERVENTIONS

The patient underwent chemotherapy.

OUTCOMES

In the first two complete remission periods, we found significantly increased numbers of platelets and bone marrow megakaryocytes, which are characteristic of ET. After the third chemotherapy phase, the disease relapsed; the platelet count was reduced and continued to decrease. When disease relapsed, her family abandoned treatment.

LESSONS

These observations of our case raise two possibilities: either transient posttreatment thrombocythemia is a feature of AML with JAK2 V617F mutation, or this was a case of secondary AML. Additional information is required to reach better conclusions on the connection between AML and JAK2 mutations.

The co-occurrence of driver mutations in chronic myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by proliferation of one or more elements of the myeloid lineage. Key genetic aberrations include the BCR-ABL1 gene rearrangement in Philadelphia chromosome-positive chronic myelogenous leukemia (CML) and JAK2/MPL/CALR aberrations in Philadelphia chromosome-negative MPNs. While thought to be mutually exclusive, occasional isolated reports of coexistence of BCR-ABL1 and JAK2, and JAK2 with MPL or CALR aberrations have been described. Given the paucity of data, clinical characteristics and outcome of patients harboring concurrent Philadelphia-positive and Philadelphia-negative mutations or dual Philadelphia-negative driver mutations have not been systematically evaluated, and their clinical relevance is largely unknown. It is difficult to determine the true relevance of co-existing driver mutations on outcomes given the rarity of its occurrence. In this case series, we describe those patients who had dual driver mutations detected at any point during the course of their disease and characterized their clinical and laboratory features, bone marrow pathology, and overall disease course.

The relevance of a low JAK2V617F allele burden in clinical practice: a monocentric study

Since low JAK2^V617F allele burden (AB) has been detected also in healthy subjects, its clinical interpretation may be challenging in patients with chronic myeloproliferative neoplasms (MPNs). We tested 1087 subjects for JAK2^V617F mutation on suspicion of hematological malignancy. Only 497 (45.7%) patients were positive. Here we present clinical and laboratory parameters of a cohort of 35/497 patients with an AB ≤ 3%.

Overall, 22/35 (62.9%) received a WHO-defined diagnosis of MPN and in 14/35 cases (40%) diagnosis was supported by bone marrow (BM) histology (‘’Histology-based’’ diagnosis). In patients that were unable or refused to perform BM evaluation, diagnosis relied on prospective clinical observation (12 cases, 34.3%) and molecular monitoring (6 cases, 17.1%) (‘’Clinical-based’’ or ‘’Molecular-based’’ diagnosis, respectively). In 11/35 (31.4%) patients, a low JAK2^V617F AB was not conclusive of MPN. The probability to have a final hematological diagnosis (ET/PV/MF) was higher in patients with thrombocytosis than in patients with polyglobulia (73.7% vs 57.1%, respectively). The detection of AB ≥ 0.8% always corresponded to an overt MPN phenotype. The repetition of JAK2^V617F evaluation over time timely detected the spontaneous expansion (11 cases) or reduction (4 cases) of JAK2^V617F-positive clones and significantly oriented the diagnostic process.

Our study confirms that histology is relevant to discriminate small foci of clonal hematopoiesis with uncertain clinical significance from a full blown disease. Remarkably, our data suggest that a cut-off of AB ≥ 0.8% is very indicative for the presence of a MPN. Monitoring of the AB over time emerged as a convenient and non-invasive method to assess clonal hematopoiesis expansion.

Summary and Review of the Abstracts on Philadelphia-Negative Myeloproliferative Neoplasms Presented at Haematocon 2017

There are lot of grey zones in Philadelphia negative chronic myeloproliferative neoplasms (CMPNs) and that's the reason they are in hit list of researchers. Having a spectrum of disorders their diagnosis is very important and especially to differentiate from each other since they overlap with each other in many ways. Diagnosis doesn't start from lab but with clinical phenotype. Clinical phenotype not only able to provide us the diagnosis but also helps in management of the disease per se. When diagnosis comes, the old timer but an evergreen morphology plays an important role which along with the newer generation tool "molecular" helps in differentiating these disorders. Lot of studies have already come up from the world. Indian data has also started coming up. When we say about the Indian data nothing holds more important role than Indian Society of Haematology and Blood Transfusion, ISHBT. This small review will cover all papers with BCR-ABL negative CMPNs which were presented at the annual national conference of the ISHBT (Haematocon 2017) which was conducted at Guwahati. These abstract papers from various reputed institutes and centres will provide a short academic journey towards ongoing research activities at these places and will able to guide us regarding Philadelphia negative CMPNs and also stimulate our brain for some left or conflicted areas.

Validating the Sensitivity of High-Resolution Melting Analysis for JAK2 V617F Mutation in the Clinical Setting

BACKGROUND

Janus kinase 2 (JAK2) plays an important role in normal hematopoietic growth factor signaling. The detection of the JAK2 V617F mutation (c.1849GNT, GTC → TTC) is crucial for the diagnosis of myeloproliferative neoplasm (MPN) and has become the essential criteria for diagnosis of MPN by the WHO. High-resolution melt (HRM) curve analysis is a nongel-based, closed-tube method, in which PCR amplification and subsequent analysis are sequentially performed in the well, making it more convenient than other scanning methodologies.

METHODS

We evaluated JAK2 V617F mutation by HRM. Twenty-nine patients diagnosed with MPN were examined. We studied the analytical sensitivity of the HRM analysis using real-time polymerase chain reaction (PCR) for identifying the JAK2 V617F mutation. Additionally, the sensitivity of HRM analysis and allele-specific PCR (AS-PCR) assay was compared.

RESULTS

The JAK2 V617F mutation was successfully discriminated at an abundance of 6% or above in HRM analysis. Both HRM analysis and AS-PCR showed 100% accuracy with detection limits of 6% and 2.5%, respectively.

CONCLUSION

HRM analysis is a fast, simple, reliable, and nonexpensive method for the detection of the JAK2 V617F mutation. However, more validation of the detection limits of HRM analysis should be performed before declaration of the analytic sensitivity of the method.

Characterization and Prognosis Significance of JAK2 (V617F), MPL, and CALR Mutations in Philadelphia-Negative Myeloproliferative Neoplasms

Background:

The discovery of somatic acquired mutations of JAK2 (V617F) in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) has not only improved rational disease classification and prognostication but also brings new understanding insight into the pathogenesis of diseases. Dosage effects of the JAK2 (V617F) allelic burden in Ph-negative MPNs may partially influence clinical presentation, disease progression, and treatment outcome.

Material and Methods:

Pyrosequencing was performed to detect JAK2 (V617F) and MPL (W515K/L) and capillary electrophoresis to identify CALR exon 9 mutations in 100 samples of Ph-negative MPNs (38.0 PV, 55 ET, 4 PMF, and 3 MPN-U).

Results:

The results showed somatic mutations of JAK2 (V617F) in 94.7% of PV, 74.5% of ET, 25.0% of PMF, and all MPN-U. A high proportion of JAK2 (V617F) mutant allele burden (mutational load > 50.0%) was predominantly observed in PV when compared with ET. Although a high level of JAK2 (V617F) allele burden was strongly associated with high WBC counts in both PV and ET, several hematological parameters (hemoglobin, hematocrit, and platelet count) were independent of JAK2 (V617F) mutational load. MPL (W515K/L) mutations could not be detected whereas CALR exon 9 mutations were identified in 35.7% of patients with JAK2 negative ET and 33.3% with JAK2 negative PMF.

Conclusions:

The JAK2 (V617F) allele burden may be involved in progression of MPNs. Furthermore, a high level of JAK2 (V617F) mutant allele appears strongly associated with leukocytosis in both PV and ET.

Low frequency of V617F mutation in JAK2 gene in Indian patients with hepatic venous outflow obstruction and extrahepatic portal venous obstruction

BACKGROUND

Hepatic venous outflow tract obstruction (HVOTO) and extrahepatic portal venous obstruction (EHPVO) are important causes of portal hypertension and related complications in India. Both these conditions result from splanchnic venous thrombosis. In recent years, a V617F somatic mutation in Janus kinase 2 (JAK2) gene which is highly specific for myeloproliferative disorders has been detected in 40 % to 50 % and 30 % to 35 % of Western patients with HVOTO and EHPVO, respectively. However, data on this mutation in these conditions from Asian countries are limited.

METHODS

We looked for JAK2 V617F mutation in Indian patients with HVOTO (n = 40, median age 31 [range 17-51] years, 21 female) and EHPVO (n = 50, median age 23 [15-70] years, 25 female) by using two separate methods. Both the methods involved polymerase chain reaction using allele-specific primers. Positive results on one or both of these techniques were confirmed using DNA sequencing.

RESULTS

None of the 40 patients with HVOTO and only 1 of 50 patients with EHPVO was found to have JAK2 V617F mutation. In the one patient who was found to have this mutation, both the PCR methods and DNA sequencing showed positive results.

CONCLUSION

Hypercoagulability associated with JAK2 V617F mutation and associated chronic myeloproliferative disorders was not a major cause of HVOTO and EHPVO in this population.

Myeloproliferative Neoplasms With Calreticulin Mutations Exhibit Distinctive Morphologic Features

OBJECTIVES

Calreticulin (CALR) mutations are present in 50% to 85% of JAK2/MPL wild-type (wt) myeloproliferative neoplasms (MPNs). The histopathologic features of CALR-mutated MPNs are unknown.

METHODS

We identified 71 patients with essential thrombocythemia (ET), primary myelofibrosis (PMF), and post-essential thrombocythemia myelofibrosis (post-ET MF) with available CALR status. CALR was assessed using capillary electrophoresis followed by Sanger sequencing confirmation. CALR status was correlated with histopathologic features.

RESULTS

The megakaryocytes of CALR-mutated PMF more often were hyperchromatic (20/21) compared with CALR-wt cases (10/14) (P = .05). CALR-mutated ET showed more megakaryocytic clustering (7/7) compared with CALR-wt cases (5/9) (P = 03). Megakaryocytes of CALR-mutated post-ET MF (8/8) had a predominance of convoluted nuclei compared with CALR-wt cases (2/4) (P = .03). CALR mutations were more frequent in post-ET MF compared with ET (P = .04).

CONCLUSIONS

CALR-mutated MPNs have a higher frequency of megakaryocytic aberrancies compared with CALR-wt cases. Patients with CALR-mutated ET appear to be more likely to develop myelofibrosis compared with patients with wt CALRUpon completion of this activity you will be able to: describe morphologic features that are associated with CALR-mutated myeloproliferative neoplasms.examine cases of essential thrombocythemia and primary myelofibrosis and predict which cases are more likely to be CALR-mutated based on histopathologic features.initiate CALR mutation testing for cases likely to have mutations.  The ASCP is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASCP designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit™ per article. Physicians should claim only the credit commensurate with the extent of their participation in the activity. This activity qualifies as an American Board of Pathology Maintenance of Certification Part II Self-Assessment Module. The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose. Exam is located at www.ascp.org/ajcpcme.

Comparative study of different methodologies to detect the JAK2 V617F mutation in chronic BCR-ABL1 negative myeloproliferative neoplasms

Objectives

A mutation in the JAK2 gene, V617F, has been identified in several BCR-ABL1 negative myeloproliferative neoplasms (MPN): polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Defining the presence or absence of this mutation is an essential part of clinical diagnostic algorithms and patient management. Here, we aimed to evaluate the performance of three PCR-based assays: Amplification Refractory Mutation System (ARMS), High-Resolution Melting analysis (HRM), and Sanger direct sequencing, and compare their results with those obtained by a PCR restriction fragment polymorphism assay (PCR-RFLP).

Design and methods

We used blood samples from 136 patients (PV=20; PMF=20; ET=28, and other MPN suspected cases=68).

Results

Comparable results were observed among the four assays in patients with PV, PMF, and MPN suspected cases. In patients with a diagnosis of ET, the JAK2 V617F mutation was detected in 67.8% of them by the PCR-ARMS and PCR-HRM assay and in 64% of them by the conventional Sanger sequence approach. The PCR-ARMS and PCR-HRM assays were 100% concordant. With these tests, only one of the 20 patients with ET and one of the three patients with clinically suspected MPN gave different results compared with those obtained by the PCR-RFLP.

Conclusions

Our results have demonstrated that the PCR-ARMS and PCR-HRM assays could detect the JAK2 V617F mutation effectively in MPN patients, but PCR-HRM assays are rapid and the most cost-effective procedures.

Myeloproliferative neoplasms: Current molecular biology and genetics

Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by increased production of mature blood cells. Philadelphia chromosome-negative MPNs (Ph-MPNs) consist of polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). A number of stem cell derived mutations have been identified in the past 10 years. These findings showed that JAK2V617F, as a diagnostic marker involving JAK2 exon 14 with a high frequency, is the best molecular characterization of Ph-MPNs. Somatic mutations in an endoplasmic reticulum chaperone, named calreticulin (CALR), is the second most common mutation in patients with ET and PMF after JAK2 V617F mutation. Discovery of CALR mutations led to the increased molecular diagnostic of ET and PMF up to 90%. It has been shown that JAK2V617F is not the unique event in disease pathogenesis. Some other genes' location such as TET oncogene family member 2 (TET2), additional sex combs-like 1 (ASXL1), casitas B-lineage lymphoma proto-oncogene (CBL), isocitrate dehydrogenase 1/2 (IDH1/IDH2), IKAROS family zinc finger 1 (IKZF1), DNA methyltransferase 3A (DNMT3A), suppressor of cytokine signaling (SOCS), enhancer of zeste homolog 2 (EZH2), tumor protein p53 (TP53), runt-related transcription factor 1 (RUNX1) and high mobility group AT-hook 2 (HMGA2) have also identified to be involved in MPNs phenotypes. Here, current molecular biology and genetic mechanisms involved in MNPs with a focus on the aforementioned factors is presented.

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.

Genomic and Clinicopathologic Features of Primary Myelofibrosis With Isolated 13q Deletion

BACKGROUND

Primary myelofibrosis (PMF) is a rare myeloproliferative stem cell disorder. The genomic features in PMF are poorly understood. Characterization of genomic alternations in PMF helps to determine their association with clinicopathologic features for further therapeutic implications.

PATIENTS AND METHODS

In this retrospective study, we investigated genomic changes using array-based comparative genomic hybridization (aCGH) in 17 PMF patients with isolated del(13q) and confirmed our aCGH findings with quantitative polymerase chain reaction (PCR) assay. We also compared the clinicopathologic features of patients with del(13q) (n = 17) with those of patients with a normal karyotype (NK) (n = 26).

RESULTS

Clinicopathologically, del(13q) PMF patients had significantly higher blast counts (P = .03) than did NK patients, who had significantly higher marrow cellularity (P = .02). The degree of bone marrow fibrosis of PMF-3 was higher in the del(13q) group than in the NK group. Splenomegaly was present significantly more often in the del(13q) PMF group than in the NK group (P = .03). Genomically, the Janus Kinase 2 V617F mutation was observed less often in del(13q) PMF patients (P = .07). The common deleted region in del(13q) was confined to 13q13-13q14.3 according to G-band karyotyping, demonstrating a minimal deleted region (MDR) of 15.323 Mb, identified using aCGH. The tumor suppressor genes, Retinoblastoma, Forkhead box protein O1, and Succinyl -CoA ligase [ADP-forming] subunit beta in the MDR were deleted, confirmed using real-time PCR to confirm our aCGH findings.

CONCLUSION

Accurate molecular characterization of del(13q) in PMF using aCGH and quantitative PCR provided further insight to define the MDR and analyze the genomic changes in del(13q) PMF patients.

Melting curve analysis after T allele enrichment (MelcaTle) as a highly sensitive and reliable method for detecting the JAK2V617F mutation

Detection of the JAK2V617F mutation is essential for diagnosing patients with classical myeloproliferative neoplasms (MPNs). However, detection of the low-frequency JAK2V617F mutation is a challenging task due to the necessity of discriminating between true-positive and false-positive results. Here, we have developed a highly sensitive and accurate assay for the detection of JAK2V617F and named it melting curve analysis after T allele enrichment (MelcaTle). MelcaTle comprises three steps: 1) two cycles of JAK2V617F allele enrichment by PCR amplification followed by BsaXI digestion, 2) selective amplification of the JAK2V617F allele in the presence of a bridged nucleic acid (BNA) probe, and 3) a melting curve assay using a BODIPY-FL-labeled oligonucleotide. Using this assay, we successfully detected nearly a single copy of the JAK2V617F allele, without false-positive signals, using 10 ng of genomic DNA standard. Furthermore, MelcaTle showed no positive signals in 90 assays screening healthy individuals for JAK2V617F. When applying MelcaTle to 27 patients who were initially classified as JAK2V617F-positive on the basis of allele-specific PCR analysis and were thus suspected as having MPNs, we found that two of the patients were actually JAK2V617F-negative. A more careful clinical data analysis revealed that these two patients had developed transient erythrocytosis of unknown etiology but not polycythemia vera, a subtype of MPNs. These findings indicate that the newly developed MelcaTle assay should markedly improve the diagnosis of JAK2V617F-positive MPNs.

Interferon-γ-induced activation of JAK1 and JAK2 suppresses tumor cell susceptibility to NK cells through upregulation of PD-L1 expression

Inhibition of JAK1 or JAK2 in human tumor cells was previously shown to increase susceptibility of these cells to NK cell lysis. In the present study, we examined the cellular mechanisms that mediate this effect in hematopoietic tumor cell lines and primary tumor cells. Incubation of tumor cells with supernatant from activated NK cells or interferon-gamma (IFNγ)-induced activation of pSTAT1 and increased expression of PD-L1 without altering expression of other activating or inhibitory NK cell ligands. These functional effects were blocked by chemical JAK inhibition or shRNAs targeting JAK1, JAK2 or STAT1. Inhibition of IFNγ signaling also prevented the upregulation of PD-L1 and blocking PD-L1 resulted in increased tumor lysis by NK cells. These results show that NK cell activation and secretion of IFNγ results in activation of JAK1, JAK2 and STAT1 in tumor cells, resulting in rapid up-regulation of PD-L1 expression. Increased expression of PD-L1 results in increased resistance to NK cell lysis. Blockade of JAK pathway activation prevents increased PD-L1 expression resulting in increased susceptibility of tumor cells to NK cell activity. These observations suggest that JAK pathway inhibitors as well as PD-1 and PD-L1 antibodies may work synergistically with other immune therapies by preventing IFN-induced inhibition of NK cell-mediated tumor cell lysis.

Coexistence of JAK2 and BCR-ABL mutation in patient with myeloproliferative neoplasm

The World Health Organisation (WHO) classifies myeloproliferative neoplasm (MPN) into BCR-ABL positive chronic myeloid leukaemia (CML Ph(+)) and Ph(-) MPN. The JAK2 V617F mutation is specific for Ph(-) MPN and occurs in approximately 50% of primary myelofibrosis. Earlier reports suggest that the occurrence of JAK2 and BCR-ABL mutations are mutually exclusive. However, recent reports have documented the coexistence of BCR-ABL and JAK2 mutation in the same patient mostly following treatment with tyrosine kinase inhibitors (TKIs). We thus report a 60-year-old male with atypical clinical and laboratory features of MPN and the presence of both BCR-ABL and JAK2 Mutations.

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.