Classification and diagnosis of myeloproliferative neoplasms: the 2008 World Health Organization criteria and point-of-care diagnostic algorithms

Retrospective Study of High Hemoglobin Levels in 56 Young Adults

Background

Erythrocytosis is a frequent request for consultation in the hematologic field. The diagnostic approach is well established in the general population but in a young adult, finding the etiology of erythrocytosis can be a real diagnostic challenge.

Methods

This is an observational retrospective unicentric study made at the Sherbrooke University Hospital Center, over a period of 20 years (1995 - 2015). Every patient aged between 16 and 35 years old with a significant elevation of hemoglobin or hematocrit was included (hemoglobin > 185 g/L and/or hematocrit > 0.52 in men; hemoglobin > 165 g/L and/or hematocrit > 0.48 in women).

Results

Totally, 426 patients met the inclusion criteria (over a total of 113,453 complete blood counts) but only 56 entered the study for investigations. The majority of patients were of male gender, 43% of the patients were obese, 59% were smokers and 38% used excess alcohol or recreational drugs. Twenty-five patients had the diagnosis of absolute erythrocytosis. Seven patients had the diagnosis of relative erythrocytosis and no cause could be identified in 24 patients. No primary erythrocytosis was found in this cohort. Among the 25 patients with secondary erythrocytosis, hypoxia was the most frequent etiology identified. Less than half of the patients in the cohort had long term follow-up. Search for JAK2 mutation and serum EPO dosage were performed in 17.9% and 23.2% of cases respectively. Seven patients were treated with aspirin and five patients had phlebotomies.

Conclusions

This retrospective study reveals an actual clinical management that is often discordant with the current recommendations and a frequent lack of follow-up after initial investigations. Harmonization of management of erythrocytosis appears to be highly desirable.

Somatic Mutations in Philadelphia Chromosome-Negative Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPN) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPN are characterized by clonal proliferation of myeloid progenitors leading to erythrocytosis, thrombocytosis, or leukocytosis, and risk of hemorrhagic and thrombotic events, as well as myelofibrosis and blast transformation. The discovery of somatic mutations in MPN, namely JAK2 V617F, JAK2 exon 12, MPL, and CALR mutations, has permitted a more specific approach to diagnosis and treatment. The prevalence of JAK2 V617F mutations is higher than 95% in PV, 50%-75% in ET and 40%-75% in PMF. JAK2 exon 12 mutations are specific of PV. A 20%-30% of patients with ET and PMF present a CALR mutation. The screening of mutations strengthens the diagnosis of MPN since 97% of MPN have at least 1 somatic mutation. Interestingly, different mutations grant different phenotype and prognosis. Of particular importance, CALR mutations grant a favorable prognosis in ET and PMF, while ASXL1 mutations confer a poorer outcome. In fact, the use of CALR/ASXL1 status for the prognostication of patients has increased clinical value and is now suggested for guidance of therapy in PMF. The increasing importance of mutations in the management of MPN warrants a more frequent revision of current diagnostic criteria and prognostic models and a better understanding of the mechanisms leading to MPN subset differentiation.

Assessment of the interlaboratory variability and robustness of JAK2V617F mutation assays: A study involving a consortium of 19 Italian laboratories

To date, a plenty of techniques for the detection of JAK2^V617F is used over different laboratories, with substantial differences in specificity and sensitivity. Therefore, to provide reliable and comparable results, the standardization of molecular techniques is mandatory.

A network of 19 centers was established to 1) evaluate the inter- and intra-laboratory variability in JAK2^V617F quantification, 2) identify the most robust assay for the standardization of the molecular test and 3) allow consistent interpretation of individual patient analysis results. The study was conceived in 3 different rounds, in which all centers had to blindly test DNA samples with different JAK2^V617F allele burden (AB) using both quantitative and qualitative assays.

The positivity of samples with an AB < 1% was not detected by qualitative assays. Conversely, laboratories performing the quantitative approach were able to determine the expected JAK2^V617F AB. Quantitative results were reliable across all mutation loads with moderate variability at low AB (0.1 and 1%; CV = 0.46 and 0.77, respectively). Remarkably, all laboratories clearly distinguished between the 0.1 and 1% mutated samples.

In conclusion, a qualitative approach is not sensitive enough to detect the JAK2^V617F mutation, especially at low AB. On the contrary, the ipsogen JAK2 MutaQuant CE-IVD kit resulted in a high, efficient and sensitive quantification detection of all mutation loads. This study sets the basis for the standardization of molecular techniques for JAK2^V617F determination, which will require the employment of approved operating procedures and the use of certificated standards, such as the recent WHO 1st International Reference Panel for Genomic JAK2^V617F.

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.

The Role of Caspase Genes Polymorphisms in Genetic Susceptibility to Philadelphia-Negative Myeloproliferative Neoplasms in a Portuguese Population

Our main aim was to evaluate the role of caspases' genes SNPs in Philadelphia-chromosome negative chronic myeloproliferative neoplasms (PN-MPNs) susceptibility. A case-control study in 133 Caucasian Portuguese PN-MPNs patients and 281 matched controls was carried out, studying SNPs in apoptosis related caspases: rs1045485 and rs1035142 (CASP8), rs1052576, rs2308950, rs1132312 and rs1052571 (CASP9), rs2227309 and rs2227310 (CASP7) and rs13006529 (CASP10). After stratification by pathology diagnosis for essential thrombocythemia (ET), female gender or JAK2 positive, there is a significant increased risk for those carrying at least one variant allele for CASP9 (C653T) polymorphism (OR 2.300 CI 95% [1.180-4.484], P = 0.014). However, when considered individually, none of the studied caspases polymorphisms was associated with PN-MPNs risk. Our results do not reveal a significant involvement of caspase genes polymorphisms on the individual susceptibility towards PN-MPNs as a whole. However, for essential thrombocythemia (ET), female gender or JAK2 positive, there is a significant increased risk to those carrying at least one variant allele for CASP9. Although larger studies are required to confirm these results and to provide conclusive evidence of association between these and other caspases variants and PN-MPNs susceptibility, these new data may contribute to a best knowledge of the pathophysiology of these disorders and, in the future, to a more rational and efficient choice of therapeutic strategies to be adopted in PN-MPNs treatment.

The role of extracellular matrix stiffness in megakaryocyte and platelet development and function

The extracellular matrix (ECM) is a key acellular structure in constant remodeling to provide tissue cohesion and rigidity. Deregulation of the balance between matrix deposition, degradation, and crosslinking results in fibrosis. Bone marrow fibrosis (BMF) is associated with several malignant and nonmalignant pathologies severely affecting blood cell production. BMF results from abnormal deposition of collagen fibers and enhanced lysyl oxidase-mediated ECM crosslinking within the marrow, thereby increasing marrow stiffness. Bone marrow stiffness has been recently recognized as an important regulator of blood cell development, notably by modifying the fate and differentiation process of hematopoietic or mesenchymal stem cells. This review surveys the different components of the ECM and their influence on stem cell development, with a focus on the impact of the ECM composition and stiffness on the megakaryocytic lineage in health and disease. Megakaryocyte maturation and the biogenesis of their progeny, the platelets, are thought to respond to environmental mechanical forces through a number of mechanosensors, including integrins and mechanosensitive ion channels, reviewed here.

MECOM, HBS1L-MYB, THRB-RARB, JAK2, and TERT polymorphisms defining the genetic predisposition to myeloproliferative neoplasms: A study on 939 patients

Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are classical myeloproliferative neoplasms (MPN), characterized by specific somatic mutations in JAK2, CALR or MPL genes. JAK2 46/1 and TERT rs2736100 polymorphisms are known to significantly predispose to MPN. This study aimed to establish the additional contribution of the recently described MECOM rs2201862, HBS1L-MYB rs9376092 and THRB-RARB rs4858647 polymorphisms to the occurrence of MPN. These three polymorphisms, along with JAK2 46/1 and TERT rs2736100 were genotyped in 939 MPN patients (454 with ET, 337 with PV and 148 with PMF) and 483 controls. MECOM rs2201862 associated significantly with each MPN entity, except for ET, and with all major molecular sub-types, especially those CALR-mutated (OR = 1.4; 95% CI = 1.1-1.8; P-value = .005). HBS1L-MYB rs9376092 associated only with JAK2 V617F-mutated ET (OR = 1.4; 95% CI = 1.1-1.7; P-value = .003). THRB-RARB rs4858647 had a weak association with PMF only (OR = 1.5; 95% CI = 1-2.1; P-value = .04). Surprisingly, JAK2 46/1 haplotype was associated significantly not only with JAK2 V617F-mutated MPN, but also with CALR-mutated MPN (OR = 1.4; 95% CI = 1.1-1.8; P-value = .01). TERT rs2736100 was associated equally strong with all MPN, regardless of phenotype or molecular sub-type. In conclusion, JAK2 46/1, TERT rs2736100 and MECOM rs2201862 are the chief predisposing polymorphisms to MPN.

Disease and treatment characteristics of polycythemia vera patients in Belgium: Results from a scientific survey

OBJECTIVE

The current survey aimed to gather predefined disease parameters and treatment strategies to characterize the polycythemia vera (PV) patient population in Belgium.

METHODS

Cross-sectional data from PV patients, seen at least once between May 2014 and May 2015 at 10 sites in Belgium, were collected in aggregated form and analyzed descriptively and quantitatively.

RESULTS

Data from 343 PV patients were collected. Of these, 174 (50.7%) were male and 256 (74.6%) were ≥60 years of age. Ninety-two (26.8%) had a prior history of thrombotic events. Considerable proportions of patients had increased hematological parameters (hematocrit > 45% [31.2%], leukocytes > 10 × 10⁹ /L [33.3%], and platelet > 400 × 10⁹ /L [38.2%]). Most patients had non-palpable spleen (284, 87.7%) and no phlebotomies during the past 6 months (197, 57.4%). Low-dose aspirin was given as thrombosis prophylaxis in 249 (72.6%) patients, while 232 (67.6%) received hydroxyurea (HU) as cytoreductive treatment. Forty-one patients (12.0%) were reported as resistant and/or intolerant to HU. Seventeen patients (5.0%) received ruxolitinib in the context of clinical trials.

CONCLUSION

This survey provides better insight into the characteristics of Belgian PV patients and currently used treatment strategies. It shows that 232 (67.6%) PV patients continue to receive HU despite being potentially HU-resistant.

CALR mutational status identifies different disease subtypes of essential thrombocythemia showing distinct expression profiles

Polycythemia vera (PV) and essential thrombocythemia (ET) are Philadelphia-negative myeloproliferative neoplasms (MPNs) characterized by erythrocytosis and thrombocytosis, respectively. Approximately 95% of PV and 50–70% of ET patients harbor the V617F mutation in the exon 14 of JAK2 gene, while about 20–30% of ET patients carry CALRins5 or CALRdel52 mutations. These ET CALR-mutated subjects show higher platelet count and lower thrombotic risk compared to JAK2-mutated patients. Here, we showed that CALR-mutated and JAK2V617F-positive CD34+ cells display different gene and miRNA expression profiles. Indeed, we highlighted several pathways differentially activated between JAK2V617F- and CALR-mutated progenitors, i.e., mTOR, MAPK/PI3K, and MYC pathways. Furthermore, we unveiled that the expression of several genes involved in DNA repair, chromatin remodeling, splicing, and chromatid cohesion are decreased in CALR-mutated cells. According to the low risk of thrombosis in CALR-mutated patients, we also found the downregulation of several genes involved in thrombin signaling and platelet activation. As a whole, these data support the model that CALR-mutated ET could be considered as a distinct disease entity from JAK2V617F-positive MPNs and may provide the molecular basis supporting the different clinical features of these patients.

Between a rux and a hard place: evaluating salvage treatment and outcomes in myelofibrosis after ruxolitinib discontinuation

Ruxolitinib is a JAK1/2 inhibitor that is effective in managing symptoms and splenomegaly related to myelofibrosis (MF). Unfortunately, many patients must discontinue ruxolitinib, at which time treatment options are not well defined. In this study, we investigated salvage treatment options and clinical outcomes among MF patients who received and discontinued ruxolitinib outside the context of a clinical trial. Among 145 patients who received ruxolitinib, 23 died while on treatment, 58 remained on treatment at time of analysis, leaving 64 people available for analysis. Development of cytopenias was the most common reason for discontinuation (38%) after median treatment time of 3.8 months (mo). The majority of patients received some form of salvage therapy after ruxolitinib discontinuation (n = 42; 66%), with allogeneic hematopoietic stem cell transplant (alloHSCT) (n = 17), being most commonly employed. Lenalidomide, thalidomide, hydroxyurea, interferon, and danazol were used with similar frequency. The response rate to salvage treatment was 26% (8 responses) and responses were most often seen with lenalidomide or thalidomide. Improved outcomes were observed in patients who underwent alloHSCT or received salvage therapy compared to those who did not receive additional therapy. Median overall survival (OS) after ruxolitinib discontinuation was 13 months. These findings show that salvage therapy can provide clinical responses after ruxolitinib discontinuation; however, these responses are rare and outcomes in this patient population are poor. This represents an area of unmet clinical need in MF.

Prognosis of Primary Myelofibrosis in the Genomic Era

Currently, prognostication in primary myelofibrosis (PMF) relies on the International Prognostic Scoring System (IPSS), dynamic IPSS (DIPSS), and DIPSS-plus, which incorporate age, blood counts, constitutional symptoms, circulating blasts, red cell transfusion need, and karyotype. Although the JAK2 V617F mutation was discovered a decade ago and MPL mutations shortly thereafter, it was the recent discovery of CALR mutations in the vast majority of JAK2/MPL-unmutated patients and recognition of the powerful impact of CALR mutations and triple-negative (JAK2/MPL/CALR-negative) status on outcome that set the stage for revision of traditional prognostic models to include molecular information. Additionally, the advent of next-generation sequencing has identified a host of previously unrecognized somatic mutations across hematologic malignancies. As in the myelodysplastic syndromes, the majority of common and prognostically informative mutations in PMF affect epigenetic regulation and mRNA splicing. Thus, a need has arisen to incorporate mutational information on genes such as ASXL1 and SRSF2 into risk stratification systems. Mutations in yet other genes appear to be important players in leukemic transformation, and new insights into disease pathogenesis are emerging. Finally, the number of prognostically detrimental mutations may affect both survival and response to ruxolitinib, which has significant implications for clinical decision making. In this review, we briefly summarize the prognostic models in use today and discuss in detail the somatic mutations commonly encountered in patients with PMF, along with their prognostic implications and role in leukemic transformation. Emerging prognostic models that incorporate new molecular information into existing systems or exclude clinical variables are also presented.

Predicting pathogenic genes for primary myelofibrosis based on a system‑network approach

The aim of the present study was to predict pathogenic genes for primary myelofibrosis (PMF) using a system‑network approach by combining protein‑protein interaction (PPI) network and gene expression data with known pathogenic genes. PMF gene expression profiles, known pathogenic genes and protein‑protein interactions were obtained. Using these data, differentially expressed genes (DEGs) were identified between PMF and normal conditions using significance analysis of microarrays, and seed genes were determined based on the intersection of known pathogenic genes and the PMF gene expression profile. A new network was constructed using the seed genes and their adjacent DEGs within the PPI network. Subsequently, a pathogenic network was extracted from the new network, and contained genes that interacted with at least two seed genes, and the candidate pathogenic genes were predicted based on the cohesion with seed genes. Cluster analysis was performed to mine the pathogenic modules from the pathogenic network, and functional analysis was performed to identify the putative biological processes of the candidate pathogenic genes. Results from the present study identified 845 DEGs between PMF and normal conditions, and 45 seed genes in PMF were screened. Subsequently, a pathogenic network comprising 103 nodes and 265 interactions was constructed, and 4 pathogenic modules (modules A‑D) were mined from the pathogenic network. There were nine candidate pathogenic genes contained within Module A and four potential pathogenic genes, including E1A‑binding protein p300, RAS‑like proto‑oncogene A, von Willebrand factor and RAF‑1 proto‑oncogene, serine/threonine kinase, were identified that may be involved in the same biological process with the seed genes. This study predicted 10 candidate pathogenic genes and several signaling pathways that may be related to the pathogenesis of PMF using a system‑network approach. These predictions may shed light on the PMF pathogenesis and may provide guidelines for future experimental verification.

Systemic Mastocytosis in Association with Small Lymphocytic Lymphoma

Patient: Female, 59

Final Diagnosis: Systemic mastocytosis in association with small lymphocytic lymphoma

Symptoms: Skin rash

Medication: —

Clinical Procedure: Bone marrow biopsy

Specialty: Hematology

Prevalence of the Janus kinase 2 V617F mutation in Philadelphia-negative myeloproliferative neoplasms in a Portuguese population

Myeloproliferative neoplasms (MPNs) result from the malignant transformation of a hematopoietic stem-cell (HSC), leading to abnormal amplification and proliferation of myeloid lineages. Identification of the Janus kinase 2 (JAK2) V617F mutation developed the knowledge of Philadelphia-negative (PN)-MPNs, contributing to and influencing the definition of the phenotype and prognostic impact. Considering the lack of Portuguese epidemiological data, the present study intends to characterize the prevalence of the JAK2 mutation in a PN-MPN versus a control Portuguese population. Caucasian Portuguese PN-MPN patients (n=133) and 281 matched control subjects were investigated. No significant differences were identified between the case and control groups concerning age distribution or smoking habits. Pathology distribution was as follows: 60.2% with essential thrombocythemia (ET), 29.3% with polycythemia vera (PV) and 10.5% with primary myelofibrosis (PMF). A total of 75.0% of patients were positive for the presence of the JAK2 V617F mutation. In addition, the prevalence of PV was 87.2%, ET was 73.4% and PMF was 50.0%. The JAK2 V617F mutation is observed in various MPN phenotypes, and has an increased incidence in ET patients and a decreased incidence in PV patients. These data may contribute to improving the knowledge of the pathophysiology of these disorders, and to a more rational and efficient selection of therapeutic strategies to be adopted, notably because most of the patients are JAK2 V617F negative.

A phase 1 study of the Janus kinase 2 (JAK2)V617F inhibitor, gandotinib (LY2784544), in patients with primary myelofibrosis, polycythemia vera, and essential thrombocythemia

Mutations in Janus kinase 2 (JAK2) are implicated in the pathogenesis of Philadelphia-chromosome negative myeloproliferative neoplasms, including primary myelofibrosis, polycythemia vera, and essential thrombocythemia. Gandotinib (LY2784544), a potent inhibitor of JAK2 activity, shows increased potency for the JAK2^V617F mutation. The study had a standard 3+3 dose-escalation design to define the maximum-tolerated dose. Primary objectives were to determine safety, tolerability, and recommended oral daily dose of gandotinib for patients with JAK2^V617F-positive myelofibrosis, essential thrombocythemia, or polycythemia vera. Secondary objectives included estimating pharmacokinetic parameters and documenting evidence of efficacy by measuring clinical improvement. Thirty-eight patients were enrolled and treated (31 myelofibrosis, 6 polycythemia vera, 1 essential thrombocythemia). The maximum-tolerated dose of gandotinib was 120mg daily, based on dose-limiting toxicities of blood creatinine increase or hyperuricemia at higher doses. Maximum plasma concentration was reached 4h after single and multiple doses, and mean half-life on day 1 was approximately 6h. Most common treatment-emergent adverse events were diarrhea (55.3%) and nausea (42.1%), a majority of which were of grade 1 severity. Best response of clinical improvement was achieved by 29% of myelofibrosis patients. A ≥50% palpable spleen length reduction was observed at any time during therapy in 20/32 evaluable patients. Additionally, ≥50% reduction in the Total Symptom Myeloproliferative Neoplasm Symptom Assessment Form Score was seen in 11/21 (52%) and 6/14 patients (43%) receiving ≥120mg at 12 and 24 weeks respectively. Gandotinib demonstrated an acceptable safety and tolerability profile, and findings at the maximum-tolerated dose of 120mg supported further clinical testing. Clinicaltrials.gov identifier: NCT01134120.

Non-Classic Myeloproliferative Neoplasms: Are We Really Aware of These Rare Diseases in Daily Practice?

Chronic neutrophilic leukaemia (CNL), chronic eosinophilic leukaemia-not otherwise specified (CEL-NOS), and myeloproliferative neoplasm (MPN), unclassifiable are rare clonal diseases, known as ‘non-classic myeloproliferative neoplasms’. They are diagnosed largely based on exclusion of underlying reactive causes by patient history, physical examination, serological tests, and imaging studies. As well as peripheral blood testing, bone marrow examination is mandatory to exclude bone marrow infiltrating conditions such as multiple myeloma, acute leukaemias, etc. Today, molecular genetic classification should be undertaken to establish accurate diagnosis, in addition to the traditional morphological classification of MPN. Therefore, molecular genetic testing should take part in the diagnostic work-up of suspected patients with rare MPN. Of CNL patients, 90% (and in some datasets 100%) have mutations in CSF3R, which has led to the addition of this finding to the diagnostic criteria for CNL. The absence of rearrangements of FIP1L1/PDGFRA, PDGFRA, PDGFRB, FGFR1, and PCM1-JAK2 fusions should prompt consideration of a diagnosis of chronic eosinophilic leukaemia-not otherwise specified. MPN, unclassifiable, the least frequent type, is considered when an MPN has definite MPN features but does not meet diagnostic criteria for either the classic or the other non-classic MPN. They all share common symptoms and findings. Transformation to acute leukaemia is still a major clinical problem. Since no standard of care exists, the treatment approach is still symptomatic for all. This is an indicator that we really need disease-modifying drugs against initial diagnostic molecular markers, such as CSF3R inhibitors, which might change the natural history of these disorders. Therefore, participation in clinical trials is mandatory for this extremely rare patient population.

A portable microfluidic platform for rapid molecular diagnostic testing of patients with myeloproliferative neoplasms

The ability to simultaneously detect JAK2 V617F and MPL W515K/L mutations would substantially improve the early diagnosis of myeloproliferative neoplasms (MPNs) and decrease the risk of arterial thrombosis. The goal of this study is to achieve a point of care testing platform for simultaneous analysis of major genetic alterations in MPN. Here, we report a microfluidic platform including a glass capillary containing polypropylene matrix that extracts genomic DNA from a drop of whole blood, a microchip for simultaneous multi-gene mutation screening, and a handheld battery-powered heating device. The µmLchip system was successfully used for point-of-care identification of the JAK2 V617F and MPL W515K/L mutations. The µmLchip assays were then validated by mutation analysis with samples from 100 MPN patients who had previously been analyzed via unlabeled probe melting curve analysis or real-time PCR. The results from the µmLchip were in perfect agreement with those from the other methods, except for one discrepant result that was negative in the unlabeled probe melting curve analysis but positive in the µmLchip. After T-A cloning, sequences of cloned PCR products revealed JAK2 V617F mutation in the sample. The portable microfluidic platform may be very attractive in developing point-of-care diagnostics for MPL W515K/L and JAK2 V617F mutations.

Clinical significance of circulating microparticles in Ph- myeloproliferative neoplasms

Microparticles (MPs) are small membrane vesicles that are classified into subcategories based on their origin, such as platelet-derived MPs (PMPs), endothelial MPs (EMPs), red blood cell MPs (RMPs) and tissue factor MPs (TF + MPs). Philadelphia chromosome-negative myeloproliferative neoplasms (Ph^-MPN) are disorders characterized by abnormal haematopoiesis, thrombosis and the JAK2V617F mutation. MPs are biomarkers for procoagulant state in cancer patients, but their relevance in patients with Ph^-MPN was unclear. The present study aimed to measure MP variation in MPN patients and evaluate association with the JAK2V617F mutation and with thrombosis and splenomegaly. In total, 92 patients with MPN were enrolled in the present study, including 60 with essential thrombocythaemia (ET), 20 with polycythaemia vera (PV), and 12 with primary myelofibrosis (PMF). RMPs, PMPs, TF + MPs and EMPs were measured by flow cytometry. The levels of RMPs, PMPs, EMPs and TF + MPs in patients with Ph^-MPN were all found to be significantly increased compared with controls (P<0.05). Additionally, the levels of all four types of MPs in the PMF group were significantly increased compared with the PV group (P<0.05), and the level of RMPs in the PMF group was significantly increased compared with the ET group (P<0.05). MP levels were increased in the Ph^-MPN patients with thrombosis compared with patients without thrombosis (P<0.05). MP levels were increased in Ph^-MPN patients with splenomegaly compared with patients without splenomegaly (P<0.05). The level of PMPs in patients with the JAK2V617F mutation was increased compared with patients without the mutation (P<0.05). In conclusion, the present study showed that MPs are associated with Ph^-MPN pathogenesis, and may promote thrombosis.

Should We Screen for Janus Kinase 2 V617F Mutation in Cerebral Venous Thrombosis?

BACKGROUND

The presence of Janus Kinase 2 (JAK2) V617F mutation represents a major diagnostic criterion for detecting myeloproliferative neoplasms (MPN) and even in the absence of overt MPN, JAK2 V617F mutation is associated with splanchnic vein thrombosis. However, the actual prevalence and diagnostic value of the JAK2 V617F mutation in patients with cerebral venous thrombosis (CVT) are not known. The aims of this study were to assess the prevalence of JAK2 V617F mutation in a large group of consecutive CVT patients, to detect clinical, biological, and radiological features associated with the mutation, and to determine the long-term venous thrombosis recurrence rate in CVT patients with JAK2 mutation but without overt MPN in order to recommend the best preventive treatment.

METHODS

This was a prospective study conducted on consecutive patients with a first-ever radiologically confirmed CVT. JAK2 V617F mutation analysis was assessed in all the study subjects. JAK2 V617F-positive patients were followed up to detect new venous thrombotic events.

RESULTS

Of the 125 included subjects, 7 were found to have JAK2 V617F mutation (5.6%; 95% CI 2.3-11.2). Older age (p = 0.039) and higher platelet count (p = 0.004) were independently associated with JAK2 V617F positivity in patients without overt MPN. During a mean follow-up period of 59 (SD 46) months, 2 JAK2 V617F-positive patients presented with 4 new venous thromboembolic events.

CONCLUSIONS

Screening for the JAK2 V617F mutation in CVT patients seems to be useful even in the absence of overt MPN and/or in the presence of other risk factors for CVT because of its relatively high prevalence and the risk of thrombosis recurrence.

Leukemic transformation in patients with myeloproliferative neoplasms: a population-based retrospective study

AIM

This study determined the epidemiology of developing leukemic transformation in patients with myeloproliferative neoplasms (MPN).

METHODS

We utilized the Surveillance, Epidemiology and End Results 13 database to identify 83 cases of leukemic transformation in MPN (n = 9335).

RESULTS

The 5-year cumulative incidence of leukemic transformation was higher in male versus female (2.17 vs 1.09%; p < 0.001), and in myelofibrosis (2.19%; 95% CI: 1.36-3.34%), compared with essential thrombocythemia (0.37%; 95% CI: 0.19-0.65%) and polycythemia vera (0.72%; 95% CI: 0.46-1.07%; p < 0.001). Patients had a median survival of 2 months after leukemic transformation, worse in older patients and without any impact of prior MPN subtypes.

CONCLUSION

Myelofibrosis has a higher risk of leukemic transformation. Overall survival is dismal regardless of MPN subtypes.

TET2, ASXL1, IDH1, and IDH2 Single Nucleotide Polymorphisms in Turkish Patients with Chronic Myeloproliferative Neoplasms

We aimed to determine the genotype distribution, allele frequency, and prognostic impact of IDH1/2, TET2, and ASXL1 single nucleotide polymorphisms (SNPs) in myeloproliferative neoplasms (MPNs). TET2 (rs763480), ASXL1 (rs2208131), and IDH1 (rs11554137) variant homozygous genotype frequencies were found at rates of 1.5%, 9.2%, and 2.3%, respectively. No IDH2 SNP was identified. IDH1 and TET2 frequencies were 5% in essential thrombocythemia (ET) and 1.7% in ET and 5% in primary myelofibrosis (PMF), respectively. ASXL1 frequencies were 8.3%-10% in MPN subgroups. The TET2 mutant allele T and ASXL1 mutant allele G had the highest frequencies with 0.272 in the PMF and 0.322 in the polycythemia vera (PV) group, respectively. There was no impact of the SNPs on prognosis. IDH1 frequency in MPNs was found similar to the literature. ASXL1 frequencies were similar between ET, PV, and PMF patients. The ASXL1 and TET2 allele frequencies of the Turkish population are similar to those of the European population. The role of SNPs in MPNs might be further evaluated in larger multicenter studies.

Clinical characteristics and whole exome/transcriptome sequencing of coexisting chronic myeloid leukemia and myelofibrosis

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell (HSC) disorders that can be classified on the basis of genetic, clinical, phenotypic features. Genetic lesions such as JAK2 mutations and BCR-ABL translocation are often mutually exclusive in MPN patients and lead to essential thrombocythemia, polycythemia vera, or myelofibrosis or chronic myeloid leukemia, respectively. Nevertheless, coexistence of these genetic aberrations in the same patient has been reported. Whether these aberrations occur in the same stem cell or a different cell is unclear, but an unstable genome in the HSCs seems to be the common antecedent. In an effort to characterize the underlying genetic events that might contribute to the appearance of more than one MPN in a patient, we studied neoplastic cells from patients with dual MPNs by next-generation sequencing. We observed that most patients with two MPNs harbored mutations in genes known to contribute to clonal hematopoiesis through altered epigenetic regulation such as TET2, ASXL1/2, SRSF2, and IDH2 at varying frequencies (1%-47%). In addition, we found that some patients also harbored oncogenic mutations in N/KRAS, TP53, BRAF, EZH2, and GNAS at low frequencies, which probably represent clonal evolution. These findings support the hypothesis that hematopoietic cells from MPN patients harbor multiple genetic aberrations, some of which can contribute to clonal dominance. Acquiring mutations in JAK2/CALR/MPL or the BCR-ABL translocation probably drive the oncogenic phenotype towards a specific MPN. Further, we propose that the acquisition of BCR-ABL in these patients is frequently a secondary event resulting from an unstable genome.

Observational retrospective study of vascular modulator changes during treatment in essential thrombocythemia

Essential thrombocythemia (ET) patients are at risk of developing thrombotic events. Qualitative platelet (PLT) abnormalities and activation of endothelial cells (ECs) and PLTs are thought to be involved. Microparticles (MPs) can originate from PLTs (PMPs), ECs (EMPs), or red cells (RMPs). Previous studies have indicated that MPs contribute to ET pathophysiology. Endothelial modulators (eg, nitric oxide [NO], adrenomedullin [ADM], and endothelin-1 [ET-1]) are also involved in the pathophysiology of this condition. We hypothesized that treatments for reducing PLT count might also indirectly affect MP generation and endothelial activity by altering endothelial modulator production. The rationale of this study was that hydroxyurea (HU), a cytostatic drug largely used in ET, induces the production of a potent vasoactive agent NO in ECs. An observational retrospective study was designed to investigate the relationship between MPs, NO, ADM, and ET-1 in ET patients on treatment with HU, anagrelide (ANA), aspirin (ASA), and a group of patients before treatment. A total of 63 patients with ET diagnosis: 18 on HU + ASA, 15 on ANA + ASA, 19 on ASA only, and 11 untreated patients, and 18 healthy controls were included in this study. Blood samples were analyzed for MP (absolute total values) and functional markers (percentage values) by flow cytometry. PLT-derived MPs were studied using CD61, CD62P, CD36, and CD63, whereas endothelial-derived MPs were studied using CD105, CD62E, and CD144. Endothelial modulator markers (NO, ADM, and ET-1) were measured by ELISA. Total MP count was higher in the group treated with ANA + ASA (P < 0.01). MP markers modified in ET patients returned to levels of healthy controls following treatment, in particular, in patients on ANA treatment. NO and ADM values were higher in the HU group (P < 0.001). HU and ANA treatment also affected MP production in a cell origin-specific manner. HU and ANA, although acting via different pathways, have similar final effects. For instance, HU causes vasodilatation by increasing NO and ADM levels, whereas ANA impairs vasoconstriction by reducing ET-1. In conclusion, therapy with HU cytostatic drugs and ANA can reduce PLT count in ET, and also affect endothelial modulatory agents, with HU sustaining vasodilation and prothrombotic MP concentration, whereas ANA decreases vasoconstriction.

Magnetic sensing platform technologies for biomedical applications

Detection and quantification of a variety of micro- and nanoscale entities, e.g. molecules, cells, and particles, are crucial components of modern biomedical research, in which biosensing platform technologies play a vital role. Confronted with the drastic global demographic changes, future biomedical research entails continuous development of new-generation biosensing platforms targeting even lower costs, more compactness, and higher throughput, sensitivity and selectivity. Among a wide choice of fundamental biosensing principles, magnetic sensing technologies enabled by magnetic field sensors and magnetic particles offer attractive advantages. The key features of a magnetic sensing format include the use of commercially available magnetic field sensing elements, e.g. magnetoresistive sensors which bear huge potential for compact integration, a magnetic field sensing mechanism which is free from interference by complex biomedical samples, and an additional degree of freedom for the on-chip handling of biochemical species rendered by magnetic labels. In this review, we highlight the historical basis, routes, recent advances and applications of magnetic biosensing platform technologies based on magnetoresistive sensors.

A phase 2 study of momelotinib, a potent JAK1 and JAK2 inhibitor, in patients with polycythemia vera or essential thrombocythemia

Momelotinib is a potent inhibitor of JAK1 and JAK2 that demonstrated efficacy in patients with primary and secondary myelofibrosis. This phase 2, open-label, randomized study evaluated the efficacy and safety of oral once-daily momelotinib (100mg and 200mg) for the treatment of polycythemia vera (PV) and essential thrombocythemia (ET). The primary endpoint for PV was overall response rate (ORR), defined as the proportion of patients with hematocrit <45%, white blood cell count <10×10⁹/L, platelet count ≤400×10⁹/L, and resolution of palpable splenomegaly, each lasting ≥4 weeks. The definition of ORR for ET excluded the hematocrit component. A total of 39 patients (28 PV, 11 ET) were enrolled, with 28 patients receiving ≥12 weeks of treatment. The study was terminated due to limited efficacy. Two patients (ORR 5.1%) met the primary efficacy endpoint (both PV 200mg). Predose plasma levels of momelotinib were stable over time. A total of 31 (79.5%) patients experienced momelotinib-related adverse events (AEs), the most frequent being headache (23.1%), dizziness (18.0%), somnolence (15.4%), nausea (15.4%), and fatigue (15.4%). Three patients experienced serious AEs (7.7%), with 1 considered related to momelotinib (dyspnea). Peripheral neuropathy occurred in 7 (17.9%) patients (4 PV, 3 ET).

Practical Measures of Clinical Benefit With Ruxolitinib Therapy: An Exploratory Analysis of COMFORT-I

BACKGROUND

The phase III COMFORT (Controlled Myelofibrosis Study With Oral JAK inhibitor Treatment)-I and COMFORT-II trials in patients with intermediate-2 or high-risk myelofibrosis (MF) showed that ruxolitinib was superior to placebo and best available therapy, respectively, for improvements in spleen volume, MF-related symptoms, and overall survival (OS). However, patients managed in community settings might not have access to the methods used in the COMFORT trials. In this exploratory analysis we summarize efficacy findings of COMFORT-I using practical, community-oriented measures of patient outcomes.

PATIENTS AND METHODS

In this post hoc analysis of data from COMFORT-I we evaluated changes from baseline to week 12 in spleen size (palpable length and volume), patient-reported outcomes (Patient Global Impression of Change; Myelofibrosis Symptom Assessment Form; Patient-Reported Outcomes Measurement System Fatigue Scale), body weight, and serum albumin levels in 5 subgroups of ruxolitinib-treated patients on the basis of week 12 spleen length changes from baseline: (1-4) ≥ 50%, 25% to < 50%, 10% to < 25%, or < 10% reduction; and (5) worsening. OS was evaluated in ruxolitinib-treated patients with week 12 spleen length reductions from baseline ≥ 50%, 25% to < 50%, or < 25% (including worsening).

RESULTS

In all spleen length subgroups, including patients with worsening spleen length at week 12, ruxolitinib (n = 150) was associated with improvements in spleen volume, patient-reported symptom burden, body weight, and serum albumin levels. Greater reductions in spleen length were associated with prolonged OS.

CONCLUSION

A variety of assessment methods beyond palpable spleen length that are easily accessible in the community setting might be useful in evaluating the clinical benefit of ruxolitinib over time in patients with MF.

Megakaryocytes in Myeloproliferative Neoplasms Have Unique Somatic Mutations

Myeloproliferative neoplasms (MPNs) are a group of related clonal hemopoietic stem cell disorders associated with hyperproliferation of myeloid cells. They are driven by mutations in the hemopoietic stem cell, most notably JAK2^V617F, CALR, and MPL. Clinically, they have the propensity to progress to myelofibrosis and transform to acute myeloid leukemia. Megakaryocytic hyperplasia with abnormal features are characteristic, and it is thought that these cells stimulate and drive fibrotic progression. The biological defects underpinning this remain to be explained. In this study we examined the megakaryocyte genome in 12 patients with MPNs to determine whether there are somatic variants and whether there is any association with marrow fibrosis. We performed targeted next-generation sequencing for 120 genes associated with myeloid neoplasms on megakaryocytes isolated from aspirated bone marrow. Ten of the 12 patients had genomic defects in megakaryocytes that were not present in nonmegakaryocytic hemopoietic marrow cells from the same patient. The greatest allelic burden was in patients with increased reticulin deposition. The megakaryocyte-unique mutations were predominantly in genes that regulate chromatin remodeling, chromosome alignment, and stability. These findings show that genomic abnormalities are present in megakaryocytes in MPNs and that these appear to be associated with progression to bone marrow fibrosis.

Ruxolitinib reduces JAK2 p.V617F allele burden in patients with polycythemia vera enrolled in the RESPONSE study

In patients with polycythemia vera (PV), an elevated JAK2 p.V617F allele burden is associated with indicators of more severe disease (e.g., leukocytosis, splenomegaly, and increased thrombosis risk); however, correlations between allele burden reductions and clinical benefit in patients with PV have not been extensively evaluated in a randomized trial. This exploratory analysis from the multicenter, open-label, phase 3 Randomized Study of Efficacy and Safety in Polycythemia Vera With JAK Inhibitor INCB018424 Versus Best Supportive Care trial evaluated the long-term effect of ruxolitinib treatment on JAK2 p.V617F allele burden in patients with PV. Evaluable JAK2 p.V617F-positive patients randomized to ruxolitinib (n = 107) or best available therapy (BAT) who crossed over to ruxolitinib at week 32 (n = 97) had consistent JAK2 p.V617F allele burden reductions throughout the study. At all time points measured (up to weeks 208 [ruxolitinib-randomized] and 176 [ruxolitinib crossover]), mean changes from baseline over time in JAK2 p.V617F allele burden ranged from −12.2 to −40.0% (ruxolitinib-randomized) and −6.3 to −17.8% (ruxolitinib crossover). Complete or partial molecular response was observed in 3 patients (ruxolitinib-randomized, n = 2; ruxolitinib crossover, n = 1) and 54 patients (ruxolitinib-randomized, n = 33; ruxolitinib crossover, n = 20; BAT, n = 1), respectively. Among patients treated with interferon as BAT (n = 13), the mean maximal reduction in allele burden from baseline was 25.6% after crossover to ruxolitinib versus 6.6% before crossover. Collectively, the data from this exploratory analysis suggest that ruxolitinib treatment for up to 4 years provides progressive reductions in JAK2 p.V617F allele burden in patients with PV who are resistant to or intolerant of hydroxyurea. The relationship between allele burden changes and clinical outcomes in patients with PV remains unclear.

DNA repair genes polymorphisms and genetic susceptibility to Philadelphia-negative myeloproliferative neoplasms in a Portuguese population: The role of base excision repair genes polymorphisms

The role of base excision repair (BER) genes in Philadelphia-negative (PN)-myeloproliferative neoplasms (MPNs) susceptibility was evaluated by genotyping eight polymorphisms [apurinic/apyrimidinic endodeoxyribonuclease 1, mutY DNA glycosylase, earlier mutY homolog (E. coli) (MUTYH), 8-oxoguanine DNA glycosylase 1, poly (ADP-ribose) polymerase (PARP) 1, PARP4 and X-ray repair cross-complementing 1 (XRCC1)] in a case-control study involving 133 Caucasian Portuguese patients. The results did not reveal a correlation between individual BER polymorphisms and PN-MPNs when considered as a whole. However, stratification for essential thrombocythaemia revealed i) borderline effect/tendency to increased risk when carrying at least one variant allele for XRCC1_399 single-nucleotide polymorphism (SNP); ii) decreased risk for Janus kinase 2-positive patients carrying at least one variant allele for XRCC1_399 SNP; and iii) decreased risk in females carrying at least one variant allele for MUTYH SNP. Combination of alleles demonstrated an increased risk to PN-MPNs for one specific haplogroup. These findings may provide evidence for gene variants in susceptibility to MPNs. Indeed, common variants in DNA repair genes may hamper the capacity to repair DNA, thus increasing cancer susceptibility.

Efficacy of ALK5 inhibition in myelofibrosis

Myelofibrosis (MF) is a bone marrow disorder characterized by clonal myeloproliferation, aberrant cytokine production, extramedullary hematopoiesis, and bone marrow fibrosis. Although somatic mutations in JAK2, MPL, and CALR have been identified in the pathogenesis of these diseases, inhibitors of the Jak2 pathway have not demonstrated efficacy in ameliorating MF in patients. TGF-β family members are profibrotic cytokines and we observed significant TGF-β1 isoform overexpression in a large cohort of primary MF patient samples. Significant overexpression of TGF-β1 was also observed in murine clonal MPL^W515L megakaryocytic cells. TGF-β1 stimulated the deposition of excessive collagen by mesenchymal stromal cells (MSCs) by activating the TGF-β receptor I kinase (ALK5)/Smad3 pathway. MSCs derived from MPL^W515L mice demonstrated sustained overproduction of both collagen I and collagen III, effects that were abrogated by ALK5 inhibition in vitro and in vivo. Importantly, use of galunisertib, a clinically active ALK5 inhibitor, significantly improved MF in both MPL^W515L and JAK2^V617F mouse models. These data demonstrate the role of malignant hematopoietic stem cell (HSC)/TGF-β/MSC axis in the pathogenesis of MF, and provide a preclinical rationale for ALK5 blockade as a therapeutic strategy in MF.

Experience with ruxolitinib in the treatment of polycythaemia vera

Polycythaemia vera (PV) is a myeloproliferative neoplasm classically characterized by an erythrocytosis and is associated with a high risk of thromboembolic events, constitutional symptoms burden and risk of transformation to myelofibrosis and acute myeloid leukaemia. Therapy is directed at the haematocrit (HCT) to reduce the risk of thrombotic events and usually comprises low-dose aspirin and phlebotomy to maintain HCT at >45%. Frequently in addition, cytoreductive therapy is indicated in high-risk patients for normalizing haematological parameters to mitigate the occurrence of thromboembolic events. Unfortunately, there is no clear evidence that current therapies reduce the risk of transformation to myelofibrosis and for some a risk of a therapy related complication is unknown for example leukaemia due to hydroxycarbamide (HC). First-line therapy for treating PV remains HC or interferon, the latter most often in younger patients, especially those of childbearing age. However, therapy related intolerance or resistance is a common feature and results in limited treatment options for such patients. The discovery of the JAK2 V617F mutation and consequently targeted therapy with Janus kinase inhibitors, in particular ruxolitinib, has extended the spectrum of agents that can be used as second or third line in PV. The findings of the phase II trial RESPONSE and the preliminary data from RESPONSE 2 trial have identified a role for ruxolitinib in PV patients who are resistant or intolerant to HC. In this article, using clinical cases we demonstrate our experience with ruxolitinib highlighting the clinical benefits and limitations we encountered in clinical practice.

Splanchnic vein thrombosis in myeloproliferative neoplasms: pathophysiology and molecular mechanisms of disease

Myeloproliferative neoplasms (MPNs) are the most common underlying prothrombotic disorder found in patients with splanchnic vein thrombosis (SVT). Clinical risk factors for MPN-associated SVTs include younger age, female sex, concomitant hypercoagulable disorders, and the JAK2 V617F mutation. These risk factors are distinct from those associated with arterial or deep venous thrombosis (DVT) in MPN patients, suggesting disparate disease mechanisms. The pathophysiology of SVT is thought to derive from local interactions between activated blood cells and the unique splanchnic endothelial environment. Other mutations commonly found in MPNs, including CALR and MPL, are rare in MPN-associated SVT. The purpose of this article is to review the clinical and molecular risk factors for MPN-associated SVT, with particular focus on the possible mechanisms of SVT formation in MPN patients.

Non-invasive imaging of retinal blood flow in myeloproliferative neoplasms

PURPOSE

To study the circulation in the retinal vessels in patients with blood dyscrasia due to myeloproliferative neoplasms using non-invasive retinal imaging.

METHODS

Prospective consecutive case series of seven treatment-naïve patients with chronic myeloid leukaemia (n = 2), polycythemia vera (n = 4), essential thrombocytosis (n = 1) examined before and after cytoreductive treatment. We investigated retinal circulation with motion-contrast imaging, retinal oximetry and spectral-domain optical coherence tomography.

RESULTS

Retinal venous blood velocity increased by 8.14% (CI₉₅ 3.67% to 12.6%, p = 0.004) and retinal arterial oxygen saturation increased by 7.23% (CI₉₅ 2.9% to 11.6%, p = 0.010) at follow-up (mean 12 weeks, range 5-14 weeks) where complete haematological remission had been achieved by cytoreductive treatment. Abnormal optical coherence tomography reflectivity patterns were present at baseline in patients with chronic myeloid leukaemia and were replaced by normal patterns at follow-up. Retinopathy, in the form of cotton-wool spots and retinal haemorrhages, was found at presentation in the two patients with chronic myeloid leukaemia and in one patient with polycythemia vera. The retinopathy had resolved at follow-up in all patients.

CONCLUSION

With non-invasive retinal imaging, we were able to demonstrate increased retinal venous blood velocity, increased retinal arterial blood oxygenation and normalization of intravascular reflectivity patterns after successful treatment of myeloproliferative neoplasms. Larger prospective studies are needed to assess the prognostic value of these non-invasive imaging methods in predicting circulatory complications in myeloproliferative neoplasms.

Clinical features of mastocytosis at pediatric patients

Mastocytosis is relevant to heterogeneous disease group characterized with redundant accumulation and proliferation of mast cells in tissues. The skin form of mastocytosis is mainly occurs in children. The article contains the current data on etiology, pathogenesis, classification, clinical forms, diagnosis, prophylactics and mastocytosis treatment at children.

[Clinical evaluation of the revised International Prognostic Score of Thrombosis for essential thrombocythemia (IPSET-thrombosis) in a cohort of 746 Chinese adult patients]

Objective: To evaluate the role of the revised International Prognostic Score of Thrombosis (IPSET-thrombosis) in predicting the occurrence of thrombotic events in Chinese patients with essential thrombocythemia (ET) and to develop a thrombosis predicting model more applicable to Chinese ET patients. Methods: Medical records of 746 adult patients with an initial diagnosis of ET were retrospectively analyzed. Results: The median age at diagnosis was 52 (18-87) years, with 305 males and 441 females. According to the revised IPSET-thrombosis model, the number of very low-, low-, intermediate-, and high-risk patients were 271 (36.3%) , 223 (29.9%) , 63 (8.4%) and 189 (25.3%) , respectively. The four groups exhibited significantly different thrombosis-free survival (χ(2)=72.301, P<0.001) . Thirty-six patients were reclassified as intermediate-risk according to the revised IPSET-thrombosis instead of low-risk as per the original IPSET-thrombosis. Nineteen intermediate-risk patients as per the original IPSET-thrombosis were upgraded to high-risk according to the revised IPSET-thrombosis. Fifty-one high-risk patients as per the original IPSET-thrombosis were reclassified as low-risk in the revised IPSET-thrombosis. It suggests that the revised IPSET-thrombosis potentially avoids over- or under-treatment. In low-risk patients as per the revised IPSET-thrombosis, the rate of thrombosis in patients with cardiovascular risk factors (CVF) was higher than that in those without (16.3% vs 5.2%, χ(2)=5.264, P=0.022) , and comparable with intermediate-risk patients as per the revised IPSET-thrombosis (16.3% vs 14.3%, χ(2)=0.089, P=0.765) . As a result, a new revised IPSET-thrombosis model more applicable to Chinese ET patients was developed in which patients with CVF in the low-risk group as per the revised IPSET-thrombosis were reclassified as intermediate-risk group. Conclusion: For predicting the occurrence of thrombotic events, the revised IPSET-thrombosis model was better than the original IPSET-thrombosis model. The revised IPSET-thrombosis was optimized and a new revised IPSET-thrombosis model more applicable to Chinese ET patients was developed, and the new evidence for risk stratification and treatment of ET in Chinese was provided.

The role of the extracellular matrix in primary myelofibrosis

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm that arises from clonal proliferation of hematopoietic stem cells and leads to progressive bone marrow (BM) fibrosis. While cellular mutations involved in the development of PMF have been heavily investigated, noteworthy is the important role the extracellular matrix (ECM) plays in the progression of BM fibrosis. This review surveys ECM proteins contributors of PMF, and highlights how better understanding of the control of the ECM within the BM niche may lead to combined therapeutic options in PMF.

Safety and efficacy of ruxolitinib in splanchnic vein thrombosis associated with myeloproliferative neoplasms

Splanchnic vein thrombosis (SVT) is one of the vascular complications of myeloproliferative neoplasms (MPN). We designed a phase 2 clinical trial to evaluate safety and efficacy of ruxolitinib in reducing splenomegaly and improving disease-related symptoms in patients with MPN-associated SVT. Patients diagnosed with myelofibrosis (12 cases), polycythemia vera (5 cases) and essential thrombocythemia (4 cases) received ruxolitinib for 24 weeks in the core study period. Spleen volume was assessed by magnetic resonance imaging (MRI) and splanchnic vein circulation by echo-Doppler analysis. Nineteen patients carried JAK2V617F, one had MPLW515L, and one CALRL367fs*46 mutation. Eighteen patients had spleno-portal-mesenteric thrombosis, two had Budd-Chiari syndrome, and one had both sites involved; 16 patients had esophageal varices. Ruxolitinib was well tolerated with hematological toxicities consistent with those of patients without SVT and no hemorrhagic adverse events were recorded. After 24 weeks of treatment, spleen volume reduction ≥35% by MRI was achieved by 6/21 (29%) patients, and a ≥50% spleen length reduction by palpation at any time up to week 24 was obtained by 13/21 (62%) patients. At week 72, 8 of the 13 (62%) patients maintained the spleen response by palpation. No significant effect of treatment on esophageal varices or in splanchnic circulation was observed. MPN-related symptoms, evaluated by MPN-symptom assessment form (SAF) TSS questionnaire, improved significantly during the first 4 weeks and remained stable up to week 24. In conclusion, this trial shows that ruxolitinib is safe in patients with MPN-associated SVT, and effective in reducing spleen size and disease-related symptoms.

Individualizing Care for Patients With Myeloproliferative Neoplasms: Integrating Genetics, Evolving Therapies, and Patient-Specific Disease Burden

Individualized medicine is important for patients with myeloproliferative neoplasms (MPNs), including essential thrombocythemia, polycythemia vera, and myelofibrosis, which are heterogeneous in terms of genetic mutation profile, prognosis, disease burden, and symptoms. Status of MPN driver mutations in JAK2, CALR, and MPL (or lack of one of these mutations) and other myeloid mutations (ASXL1, SRSF2, CBL, and IDH1/2, among others) affects diagnosis and prognosis. Management begins with estimating the prognosis, disease burden including MPN symptoms, and prevention of vascular events. Allogeneic stem cell transplantation is the definitive therapy in a subset of patients with myelofibrosis, the majority of whom receive JAK inhibition with ruxolitinib to relieve splenomegaly and symptoms and to prolong survival. Ruxolitinib is now a second-line therapy in polycythemia vera, with pegylated interferon being evaluated as a potential front-line therapy compared with hydroxyurea. The therapeutic landscape is evolving to include new JAK inhibitors, which may affect cytopenias (pacritinib and momelotinib), combination therapies including ruxolitinib, and novel targets such as pentraxin and telomerase. Assessing the therapeutic efficacy (including symptom impact) and toxicity of these new approaches is necessary to determine longitudinal management of MPNs in clinical practice and is a key component of "individualizing" care for patients with MPNs.

The efficacy and safety of continued hydroxycarbamide therapy versus switching to ruxolitinib in patients with polycythaemia vera: a randomized, double-blind, double-dummy, symptom study (RELIEF)

The randomized, double-blind, double-dummy, phase 3b RELIEF trial evaluated polycythaemia vera (PV)-related symptoms in patients who were well controlled with a stable dose of hydroxycarbamide (also termed hydroxyurea) but reported PV-related symptoms. Patients were randomized 1:1 to ruxolitinib 10 mg BID (n = 54) or hydroxycarbamide (prerandomization dose/schedule; n = 56); crossover to ruxolitinib was permitted after Week 16. The primary endpoint, ≥50% improvement from baseline in myeloproliferative neoplasm -symptom assessment form total symptom score cytokine symptom cluster (TSS-C; sum of tiredness, itching, muscle aches, night sweats, and sweats while awake) at Week 16, was achieved by 43·4% vs. 29·6% of ruxolitinib- and hydroxycarbamide-treated patients, respectively (odds ratio, 1·82; 95% confidence interval, 0·82-4·04; P = 0·139). The primary endpoint was achieved by 34% of a subgroup who maintained their hydroxycarbamide dose from baseline to Weeks 13-16. In a post hoc analysis, the primary endpoint was achieved by more patients with stable screening-to-baseline TSS-C scores (ratio ≤ 2) receiving ruxolitinib than hydroxycarbamide (47·4% vs. 25·0%; P = 0·0346). Ruxolitinib treatment after unblinding was associated with continued symptom score improvements. Adverse events were primarily grades 1/2 with no unexpected safety signals. Ruxolitinib was associated with a nonsignificant trend towards improved PV-related symptoms versus hydroxycarbamide, although an unexpectedly large proportion of patients who maintained their hydroxycarbamide dose reported symptom improvement.

Kinase signaling and targeted therapy for primary myelofibrosis

The myeloproliferative neoplasms (MPNs) are somatic mutation-driven hematologic malignancies characterized by bone marrow fibrosis and the accumulation of atypical megakaryocytes with reduced polyploidization in the primary myelofibrosis subtype of the MPNs. Increasing evidence points to a dominant role of abnormal megakaryocytes in disease initiation and progression. Here we review the literature related to kinase signaling pathways relevant to megakaryocyte differentiation and proliferation, including Aurora A kinase, RhoA/ROCK, and JAK/STAT, as well as the activities of their targeted inhibitors in models of the disease. Some of these pathway inhibitors selectively induce megakaryocyte differentiation, suppress malignant proliferation, and promote polyploidization and proplatelet formation. Moreover, combining sets of these inhibitors may be an effective approach to treat and potentially cure MPN patients. For example, preclinical studies reported significant synergistic effects of the combination of an Aurora A inhibitor and JAK1/2 inhibitor, in a murine model of the primary myelofibrosis. Future basic and clinical research into the contributions of these signaling pathways to aberrant megakaryopoiesis may lead to novel effective treatments for MPN patients.