[Clonal evolution in myeloproliferative neoplasms].

Recent advances in sequencing technologies have clarified the driver gene landscape in Philadelphia chromosomenegative (Ph-) myeloproliferative neoplasms (MPNs) and progressed understanding of MPN pathogenesis. Beyond mutations in the main three drivers of MPN, namely JAK2, MPL and CALR, somatic mutations in the epigenetic regulators and RNA splicing factors have been identified and their association with transformation to myelofibrosis and acute myeloid leukemia have been determined. Clonal expansion of hematopoietic cells with driver mutations (clonal hematopoiesis) has been detected in healthy individuals, especially in elderly people. In MPN patients, however, initial driver mutations such as those in JAK2 and DNMT3A have been shown to be acquired in utero or during childhood. In this review, I will summarize the recent findings about clonal evolution in MPN and the role of driver mutations.

Evaluation of Methods for Identifying Poultry Wing Rinses With Salmonella Concentrations Greater Than or Equal to 10 CFU/mL.

In the United States, the Proposed Regulatory Framework to Reduce Salmonella Illnesses Attributable to Poultry published by the Food Safety and Inspection Service (FSIS) has highlighted the need for simple, rapid methods that identify poultry wing rinse samples harboring Salmonella concentrations ≥10 CFU/mL. One of eight cold-stressed and nutrient-starved Salmonella strains was inoculated into post-chill two-joint poultry wing rinses (48 turkey and 72 chicken) at levels from 0.22 to 3.79 log CFU/mL, and then measured by 3-tube Most Probable Number (MPN), BioMerieux GENE-UP QUANT, Hygiena BAX SalQuant, and novel threshold methods. The MPN lower limit of quantification (LLQ) for Salmonella was -0.96 log CFU/mL. MPN overestimated the inoculated Salmonella level by 0.05 ± 0.35 log CFU/mL. The GENE-UP QUANT Salmonella method (LLQ = 1.00 log CFU/mL) underestimated the inoculated Salmonella level by 0.05 ± 0.51 log CFU/mL. The BAX SalQuant method (LLQ = 0.00 log CFU/mL) underestimated the inoculated Salmonella level by 1.21 ± 0.78 log CFU/mL. Threshold test methods with Poisson probabilities of 0.95 (PiLOT-95), 0.86 (PiLOT-86), 0.63 (PiLOT-63), and 0.50 (PiLOT-50) were developed to identify poultry wing rinses harboring Salmonella levels ≥10 CFU. MPN was 93.1%, accurate for determining if Salmonella levels in poultry wing rinses were ≥10 CFU/mL, but MPN costs and time requirements can be prohibitive for most laboratories. GENE-UP quantification was 86.1% accurate, but the GENE-UP method requires equipment and technical expertise that some food safety laboratories may not possess. BAX quantification had the lowest accuracy; 58.4%. PiLOT threshold test accuracies ranged from 83.2% for PiLOT-50 to 93.1% for PiLOT-86. The PiLOT threshold tests are simple and can be adapted to identify many environmental or food samples containing Salmonella exceeding any user-defined concentration threshold.

Germline genetic variants that predispose to myeloproliferative neoplasms and hereditary myeloproliferative phenotypes.

Epidemiological evidence of familial predispositions to myeloid malignancies and myeloproliferative neoplasms (MPN) has long been recognised, but recent studies have added to knowledge of specific germline variants in multiple genes that contribute to the familial risk. These variants may be common risk alleles in the general population but have low penetrance and cause sporadic MPN, such as the JAK2 46/1 haplotype, the variant most strongly associated with MPN. Association studies are increasingly identifying other MPN susceptibility genes such as TERT, MECOM, and SH2B3, while some common variants in DDX41 and RUNX1 appear to lead to a spectrum of myeloid malignancies. RBBP6 and ATM variants have been identified in familial MPN clusters and very rare germline variants such as chromosome 14q duplication cause hereditary MPN with high penetrance. Rarely, there are hereditary non-malignant diseases with an MPN-like phenotype. Knowledge of those genes and germline genetic changes which lead to MPN or diseases that mimic MPN helps to improve accuracy of diagnosis, aids with counselling regarding familial risk, and may contribute to clinical decision-making. Large scale population exome and genome sequencing studies will improve our knowledge of both common and rare germline genetic contributions to MPN.

Genomic Landscape of Myelodysplastic/Myeloproliferative Neoplasms: A Multi-Central Study.

The accurate diagnosis and classification of myelodysplastic/myeloproliferative neoplasm (MDS/MPN) are challenging due to the overlapping pathological and molecular features of myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). We investigated the genomic landscape in different MDS/MPN subtypes, including chronic myelomonocytic leukemia (CMML; n = 97), atypical chronic myeloid leukemia (aCML; n = 8), MDS/MPN-unclassified (MDS/MPN-U; n = 44), and MDS/MPN with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T; n = 12). Our study indicated that MDS/MPN is characterized by mutations commonly identified in myeloid neoplasms, with TET2 (52%) being the most frequently mutated gene, followed by ASXL1 (38.7%), SRSF2 (34.7%), and JAK2 (19.7%), among others. However, the distribution of recurrent mutations differs across the MDS/MPN subtypes. We confirmed that specific gene combinations correlate with specific MDS/MPN subtypes (e.g., TET2/SRSF2 in CMML, ASXL1/SETBP1 in aCML, and SF3B1/JAK2 in MDS/MPN-RS-T), with MDS/MPN-U being the most heterogeneous. Furthermore, we found that older age (≥65 years) and mutations in RUNX1 and TP53 were associated with poorer clinical outcomes in CMML (p < 0.05) by multivariate analysis. In MDS/MPN-U, CBL mutations (p < 0.05) were the sole negative prognostic factors identified in our study by multivariate analysis (p < 0.05). Overall, our study provides genetic insights into various MDS/MPN subtypes, which may aid in diagnosis and clinical decision-making for patients with MDS/MPN.

TLE3 Is a Novel Fusion Partner of JAK2 in Myeloid/Lymphoid Neoplasm With Eosinophilia Responding to JAK2 Inhibition.

Chromosomal rearrangements involving Janus kinase 2 (JAK2) are rare but recurrent findings in lymphoid or myeloid neoplasia. Detection of JAK2 fusion genes is important as patients with aberrantly activated JAK2 may benefit from treatment with tyrosine kinase inhibitors such as ruxolitinib. Here, we report a novel fusion gene between the transcriptional co-repressor-encoding gene transducin-like enhancer of split 3 (TLE3) and JAK2 in a patient initially diagnosed with chronic eosinophilic leukemia with additional mutations in PTPN11 and NRAS. The patient was successfully treated with the JAK2 inhibitor ruxolitinib for 8 months before additional somatic mutations were acquired and the disease progressed into an acute lymphoblastic T-cell leukemia/lymphoma. The present case shows similarities to previously reported cases with PCM1::JAK2 and BCR::JAK2 with regard to disease phenotype and response to ruxolitinib, and importantly, provides an example that also patients harboring other JAK2 fusion genes may benefit from treatment with JAK2 inhibitors.

Chronic Myelomonocytic Leukemia and Atypical Chronic Myeloid Leukemia: A National Analysis.

BACKGROUND: Myelodysplastic/myeloproliferative overlap syndromes (MDS/MPN) are rare blood cancers characterized by concomitant myeloid hyperplasia and dysplasia. These heterogenous disorders include chronic myelomonocytic leukemia (CMML) and atypical chronic myeloid leukemia (aCML). METHODS: Using two large national cancer databases to examine a total of 15,704 CMML and 702 aCML patients, we report the largest study to date on the incidence, survival and demographic characteristics of CMML and aCML in the United States. RESULTS: Overall age-adjusted incidence of CMML and aCML was 0.63 per 100,000 Americans per year and 0.03 per 100,000 per year, respectively. CMML incidence in the U.S. was noted to rise steadily in the years between 2001 and 2019. Median patient age was 75 and 72 years for CMML and aCML, and the majority of CMML and aCML patients were male (62.9% and 62.0%) and White (90.1% and 86.3%). Median OS was 17.4 months for CMML, and 15.2 months for aCML. Multivariate Cox regression demonstrated features associated with reduced survival, including increasing age, comorbidities, Medicaid insurance status, and low-income residential zip code, highlighting survival disparities in underinsured and socioeconomically disadvantaged patients. In CMML, Black race was associated with inferior survival, while female sex, management at an academic center, and later calendar-year of diagnosis were associated with improved OS. CONCLUSION: These findings underscore the need to better understand the biological basis for such differences in survival and reflect the importance of access to specialized care for patients with these rare disorders.

Atypical chronic myeloid leukemia found in a patient with eosinophilia for six years: a case report.

BACKGROUND: Atypical chronic myeloid leukemia (aCML) is a highly aggressive type of blood cancer that falls under the category of myelodysplastic/myeloproliferative neoplasms (MDS/MPN). In the fifth edition of the WHO classification of tumors, this category has been renamed MDS/MPN with neutrophilia. Although eosinophilia is commonly observed in blood cancers, it is rarely seen in aCML. CASE PRESENTATION: This study presents a case of aCML that was diagnosed six years after the patient developed eosinophilia. The patient had undergone tests to rule out other primary and secondary diseases, but the eosinophilia remained unexplained. Treatment with corticosteroids and hydroxyurea had proven ineffective. Six years later, the patient experienced an increase in white blood cells, primarily neutrophils. After ruling out other possible diagnoses, a combination of morphologic and molecular genetic findings led to the diagnosis of aCML. The patient responded well to treatment with azacitidine. CONCLUSIONS: This study summarizes the current state of aCML diagnosis and management and discusses the possible connection between eosinophilia and aCML.

Updates in biology, classification, and management of acute myeloid leukemia with antecedent hematologic disorder and therapy related acute myeloid leukemia.

Acute myeloid leukemia with antecedent hematologic disorder (AHD-AML) and therapy related AML (t-AML) constitute a heterogenous disease with inferior outcomes. It is often characterized by high-risk cytogenetic and molecular alterations associated with AHD or prior cancer therapy. Historically, the standard of care treatment has been intensive induction with "7 + 3", with an improved overall response rate and survival with CPX-351. Results from large registry-based studies suggested that allogeneic hematopoietic stem cell transplant is preferable to consolidation chemotherapy alone for achieving long-term survival in patients with AHD-AML. Prevalence of high-risk genetic features and advanced age and comorbidities in patients make AHD-AML and t-AML clinically challenging subgroups to treat with intensive approaches. Recent reports on less intensive treatment options, particularly the hypomethylating agent-venetoclax combination, have shown encouraging response rates in these patients. However, emerging resistance mechanisms compromise duration of response and overall survival. Several novel agents targeting apoptotic machinery, signaling pathways, and immune checkpoints are under clinical investigation, with an aim to truly improve overall outcomes in this subgroup. We reviewed updates in biology, classification, and clinical data comparing safety and efficacy of intensive and less intensive treatment options, and summarized ongoing studies with promising novel therapies in AHD-AML and t-AML.

FRACTION: protocol of a phase II study of Fedratinib and Nivolumab combination in patients with myelofibrosis and resistance or suboptimal response to JAK-inhibitor treatment of the German MPN study group (GSG-MPN).

Development of Janus-kinase (JAK) inhibitors has revolutionized the therapeutic landscape for patients with myeloproliferative neoplasia (MPN). Following approval of the first JAK1/2-inhibitor Ruxolitinib, symptoms of this inflammatory disease, characterized by splenomegaly, release of inflammatory cytokines and appearance of thrombosis, could be effectively reduced for the first time. However, JAK-inhibitor treatment is limited in several aspects: 1) duration of response: 3 years after initiation of therapy more than 50% of patients have discontinued JAK-inhibitor treatment due to lack of efficacy or resistance; 2) reduction of disease burden: while effective in reducing inflammation and constitutional symptoms, JAK-inhibitors fail to reduce the malignant clone in the majority of patients and therefore lack long-term efficacy. Early clinical trials for patients with myelofibrosis (MF) have tried to address these issues for patients with suboptimal response to Ruxolitinib therapy while combination therapies with Fedratinib are rare. Recent reports provided first evidence on how the JAK2-V617F mutated myeloid cells may influence T-cell responses. JAK2-V617F promoted the synthesis of PD-L1 in MPN cells leading to limited anti-neoplastic T-cell responses, metabolic changes in T-cells and eventually JAK2-V617F-driven immune-escape of MPN cells. These findings may facilitate the use of immunotherapeutic approaches for JAK-mutated clones. Immune checkpoints refer to a variety of inhibitory pathways that are crucial for maintaining self-tolerance and modulating the duration and amplitude of physiological immune responses in peripheral tissues in order to minimize collateral tissue damage. The FRACTION study is a single arm, open label Phase II trial investigating the combination of Fedratinib with the PD-1 inhibitor Nivolumab in patients with myelofibrosis and suboptimal or lack of response to JAK-inhibitor therapy. Over a 12 months period the trial assesses longer term outcomes, particularly the effects on clinical outcomes, such as induction of clinical remissions, quality of life and improvement of anemia. No prospective clinical trial data exist for combinations of JAK- and immune-checkpoint-inhibitors in the planned MF study population and this study will provide new findings that may contribute to advancing the treatment landscape for MF patients with suboptimal responses and limited alternatives.

Maximum likelihood estimators for colony-forming units.

Measuring the abundance of microbes in a sample is a common procedure with a long history, but best practices are not well-conserved across microbiological fields. Serial dilution methods are commonly used to dilute bacterial cultures to produce countable numbers of colonies, and from these counts, to infer bacterial concentrations measured in colony-forming units (CFUs). The most common methods to generate data for CFU point estimates involve plating bacteria on (or in) a solid growth medium and counting their resulting colonies or counting the number of tubes at a given dilution that have growth. Traditionally, these types of data have been analyzed separately using different analytic methods. Here, we build a direct correspondence between these approaches, which allows one to extend the use of the most probable number method from the liquid tubes experiments, for which it was developed, to the growth plates by viewing colony-sized patches of a plate as equivalent to individual tubes. We also discuss how to combine measurements taken at different dilutions, and we review several ways of analyzing colony counts, including the Poisson and truncated Poisson methods. We test all point estimate methods computationally using simulated data. For all methods, we discuss their relevant error bounds, assumptions, strengths, and weaknesses. We provide an online calculator for these estimators.Estimation of the number of microbes in a sample is an important problem with a long history. Yet common practices, such as combining results from different measurements, remain sub-optimal. We provide a comparison of methods for estimating abundance of microbes and detail a mapping between different methods, which allows to extend their range of applicability. This mapping enables higher precision estimates of colony-forming units (CFUs) using the same data already collected for traditional CFU estimation methods. Furthermore, we provide recommendations for how to combine measurements of colony counts taken across dilutions, correcting several misconceptions in the literature.

Impact of gender representativeness in online symptom survey and clinical trial participation among patients with myeloproliferative neoplasms.

Patients with myeloproliferative neoplasms (MPNs) face chronic symptom burden. Online symptom assessment studies allow for recruitment of large numbers of motivated patients, but patient self-selection can lead to sampling bias. This study evaluated how gender representativeness in MPN symptom surveys and trials impacted symptom score mean estimates, using data from 4825 survey respondents and 291 trial participants with MPNs. The survey data showed that men participated at a rate roughly 50% less than what would be expected based on prevalence, and women reported higher scores than men on average for six of 10 symptoms. Together, this led to potential over estimation in six of 10 symptom score means (ranging from 5.8% to 15.3% overestimated). The trial data showed less gender-based sampling bias compared to the survey data. Studies utilizing online symptom surveys should implement study design features to recruit more men, assess for gender participation imbalances, and provide weighted estimates where appropriate.

Mathematical modelling of stem and progenitor cell dynamics during ruxolitinib treatment of patients with myeloproliferative neoplasms.

Introduction: The Philadelphia chromosome-negative myeloproliferative neoplasms are a group of slowly progressing haematological malignancies primarily characterised by an overproduction of myeloid blood cells. Patients are treated with various drugs, including the JAK1/2 inhibitor ruxolitinib. Mathematical modelling can help propose and test hypotheses of how the treatment works. Materials and methods: We present an extension of the Cancitis model, which describes the development of myeloproliferative neoplasms and their interactions with inflammation, that explicitly models progenitor cells and can account for treatment with ruxolitinib through effects on the malignant stem cell response to cytokine signalling and the death rate of malignant progenitor cells. The model has been fitted to individual patients' data for the JAK2 V617F variant allele frequency from the COMFORT-II and RESPONSE studies for patients who had substantial reductions (20 percentage points or 90% of the baseline value) in their JAK2 V617F variant allele frequency (n = 24 in total). Results: The model fits very well to the patient data with an average root mean square error of 0.0249 (2.49%) when allowing ruxolitinib treatment to affect both malignant stem and progenitor cells. This average root mean square error is much lower than if allowing ruxolitinib treatment to affect only malignant stem or only malignant progenitor cells (average root mean square errors of 0.138 (13.8%) and 0.0874 (8.74%), respectively). Discussion: Systematic simulation studies and fitting of the model to the patient data suggest that an initial reduction of the malignant cell burden followed by a monotonic increase can be recapitulated by the model assuming that ruxolitinib affects only the death rate of malignant progenitor cells. For patients exhibiting a long-term reduction of the malignant cells, the model predicts that ruxolitinib also affects stem cell parameters, such as the malignant stem cells' response to cytokine signalling.

Translation, Cultural Adaptation, and Validation into Romanian of the Myeloproliferative Neoplasm Symptom Assessment Form-Total Symptom Score (MPN-SAF TSS or MPN-10) Questionnaire.

Background: Patients with myeloproliferative neoplasms (MPNs) experience a high disease-related symptom burden. A specific instrument to evaluate quality of life (QoL), i.e., the MPN Symptom Assessment Form Total Symptom Score (MPN-SAF TSS; MPN-10), was developed. We conducted the translation, cultural adaptation, and validation into Romanian of the MPN-10. Methods: We translated the MPN-10 and tested its psychometric properties. Results: We recruited 180 MPN patients: 66 polycythemia vera (36.67%), 61 essential thrombocythemia (33.89%), 51 primary and secondary myelofibrosis (SMF) (28.33%), and 2 MPN-unclassifiable (1.11%). The mean TSS was 19.51 ± 16.51 points. Fatigue, inactivity, and concentration problems were the most cumbersome symptoms. We detected scoring differences between MPN subtypes regarding weight loss (p < 0.001), fatigue (p = 0.006), early satiety (p = 0.007), night sweats (p = 0.047), pruritus (p = 0.05), and TSS (p = 0.021). There were strong positive associations between TSS and inactivity, fatigue, and concentration problems, and moderate negative correlations between QoL scores and all MPN-10 items. Cronbach's α internal consistency coefficient was 0.855. The Kaiser-Meyer-Olkin construct validity test result was 0.870 and the Bartlett Sphericity Test was significant (p < 0.001). Symptom scores were loaded into one single factor according to the exploratory factor analysis. Conclusions: The Romanian MPN-10 version displayed excellent psychometric properties and is a reliable instrument for assessing symptom burden and QoL in Romanian MPN patients.

Overlapping Stromal Alterations in Myeloid and Lymphoid Neoplasms.

Myeloid and lymphoid neoplasms share the characteristics of potential bone marrow infiltration as a primary or secondary effect, which readily leads to hematopoietic insufficiency. The mechanisms by which clonal malignant cells inhibit normal hematopoietic stem and progenitor cells (HSPCs) in the bone marrow (BM) have not been unraveled so far. Given the pivotal role of mesenchymal stromal cells (MSCs) in the regulation of hematopoiesis in the BM niche it is assumed that MSCs also play a relevant role in the pathogenesis of hematological neoplasms. We aimed to identify overlapping mechanisms in MSCs derived from myeloid and lymphoid neoplasms contributing to disease progression and suppression of HSPCs to develop interventions that target these mechanisms. MSCs derived from healthy donors (n = 44) and patients diagnosed with myeloproliferative neoplasia (n = 11), myelodysplastic syndromes (n = 16), or acute myeloid leukemia (n = 25) and B-Non-Hodgkin lymphoma (n = 9) with BM infiltration and acute lymphoblastic leukemia (n = 9) were analyzed for their functionality and by RNA sequencing. A reduced growth and differentiation capacity of MSCs was found in all entities. RNA sequencing distinguished both groups but clearly showed overlapping differentially expressed genes, including major players in the BMP/TGF and WNT-signaling pathway which are crucial for growth, osteogenesis, and hematopoiesis. Functional alterations in healthy MSCs were inducible by exposure to supernatants from malignant cells, implicating the involvement of these factors in disease progression. Overall, we were able to identify overlapping factors that pose potential future therapeutic targets.

Neutrophil-specific expression of JAK2-V617F or CALRmut induces distinct inflammatory profiles in myeloproliferative neoplasia.

BACKGROUND: Neutrophils play a crucial role in inflammation and in the increased thrombotic risk in myeloproliferative neoplasms (MPNs). We have investigated how neutrophil-specific expression of JAK2-V617F or CALRdel re-programs the functions of neutrophils. METHODS: Ly6G-Cre JAK2-V617F and Ly6G-Cre CALRdel mice were generated. MPN parameters as blood counts, splenomegaly and bone marrow histology were compared to wild-type mice. Megakaryocyte differentiation was investigated using lineage-negative bone marrow cells upon in vitro incubation with TPO/IL-1ß. Cytokine concentrations in serum of mice were determined by Mouse Cytokine Array. IL-1α expression in various hematopoietic cell populations was determined by intracellular FACS analysis. RNA-seq to analyse gene expression of inflammatory cytokines was performed in isolated neutrophils from JAK2-V617F and CALR-mutated mice and patients. Bioenergetics of neutrophils were recorded on a Seahorse extracellular flux analyzer. Cell motility of neutrophils was monitored in vitro (time lapse microscopy), and in vivo (two-photon microscopy) upon creating an inflammatory environment. Cell adhesion to integrins, E-selectin and P-selection was investigated in-vitro. Statistical analysis was carried out using GraphPad Prism. Data are shown as mean ± SEM. Unpaired, two-tailed t-tests were applied. RESULTS: Strikingly, neutrophil-specific expression of JAK2-V617F, but not CALRdel, was sufficient to induce pro-inflammatory cytokines including IL-1 in serum of mice. RNA-seq analysis in neutrophils from JAK2-V617F mice and patients revealed a distinct inflammatory chemokine signature which was not expressed in CALR-mutant neutrophils. In addition, IL-1 response genes were significantly enriched in neutrophils of JAK2-V617F patients as compared to CALR-mutant patients. Thus, JAK2-V617F positive neutrophils, but not CALR-mutant neutrophils, are pathogenic drivers of inflammation in MPN. In line with this, expression of JAK2-V617F or CALRdel elicited a significant difference in the metabolic phenotype of neutrophils, suggesting a stronger inflammatory activity of JAK2-V617F cells. Furthermore, JAK2-V617F, but not CALRdel, induced a VLA4 integrin-mediated adhesive phenotype in neutrophils. This resulted in reduced neutrophil migration in vitro and in an inflamed vessel. This mechanism may contribute to the increased thrombotic risk of JAK2-V617F patients compared to CALR-mutant individuals. CONCLUSIONS: Taken together, our findings highlight genotype-specific differences in MPN-neutrophils that have implications for the differential pathophysiology of JAK2-V617F versus CALR-mutant disease.

A comparison of the MPN and pour plate methods for estimating shellfish contamination by Escherichia coli.

AIMS: Shellfish production areas are classified for suitability for human consumption using counts of Escherichia coli in shellfish samples. Two alternative laboratory methods are approved in the European Union and UK for measuring E. coli in shellfish samples; the most probable number (MPN) and pour plate methods. These methods have inherently different statistical uncertainty and may give different counts for the same sample. Using two approaches: simulated data and spiking experiments, we investigate the theoretical properties of the two methods to determine their reliability for shellfish waters classification. METHODS AND RESULTS: Assuming a Poisson distribution of E. coli in shellfish samples, we simulate concentrations in 10 000 samples using the MPN and pour plate methods. We show that for higher concentrations of E. coli the pour plate method becomes increasingly more reliable than the MPN method. The MPN method has higher probabilities than pour plate of generating results exceeding shellfish classification thresholds, while conversely having higher probabilities of failing to detect counts that exceed regulatory thresholds. The theoretical analysis also demonstrates that the MPN method can produce genuine extreme outliers, even when E. coli are randomly distributed within the sampled material. A laboratory spiking experiment showed results consistent with the theoretical analysis, suggesting the Poisson assumption used in the theoretical analysis is reasonable. CONCLUSION: The large differences in statistical properties between the pour plate and MPN methods should be taken into consideration in classifying shellfish beds, with the pour plate method being more reliable over the crucial range of E. coli concentrations used to determine class boundaries.

Viability assessed with the most probable number dilution culture method after chemical treatment of ballast water reveals the presence of false negatives from an approved vital stain method.

The present study compares the CMFDA/FDA + motility- and the Most Probable Number (MPN) Dilution Culture + Motility methods for testing the viability of ≥10-<50 µm organisms in chlorine treated ballast water. The results of both methods were within the regulatory compliance criterion <10 organisms/mL, but the MPN-method revealed that growth-outs did occur. While the CMFDA/FDA method showed <0.5 organisms/mL, the MPN-method gave approx. 6 organisms/mL. This demonstrated that false negatives, i.e. living but not stained organisms, may occur when using the CMFDA/FDA-method for compliance testing of chemical treated ballast water. Organisms surviving the treatment were primarily the dinoflagellate Scrippsiella sp. and various coccoid chlorophytes present in a brackish- and freshwater test, respectively. It is suggested that their resilience to the chemical treatment is the ability to transform into a temporary cyst (Scrippsiella sp.) or the presence of a chemical resistant cell wall (certain chlorophytes).

Recent advances in JAK2 inhibition for the treatment of myelofibrosis.

INTRODUCTION: Myelofibrosis (MF) is a BCR-ABL-negative myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, cytopenias, a potential for leukemic transformation, and increased mortality. Patients who are ineligible for stem cell transplant rely on pharmacologic therapies of noncurative intent, whose cornerstone consists of JAK inhibitors (JAKi). While current JAKi are efficacious in controlling symptoms and splenic volume, none meaningfully reduce clonal burden nor halt disease progression, and patients oftentimes develop JAKi intolerant, relapsed, or refractory MF. As such, there remains an urgent necessity for second-line options and novel therapies with disease-modifying properties. AREAS COVERED: In this review, we delineate the mechanistic rationale, along with the latest safety and efficacy data, of investigational JAKi-based MF treatment strategies, with a focus on JAKi monotherapies and combinations of novel agents with approved JAKi. Our literature search consisted of extensive review of PubMed and clinicaltrials.gov. EXPERT OPINION: A myriad of promising MF-directed therapies are in late-phase studies. Following their approval, treatment selection should be tailored to patient-specific treatment goals and disease characteristics, with an emphasis on combination therapies of JAKi with novel agents of differing mechanistic targets that possess anti-clonal properties, in attempt to alter disease course and concurrently limit dose-dependent JAKi toxicities.

Myeloproliferative neoplasm with eosinophilia and coexisting BCR::ABL1 and PDGFRB rearrangement: favorable and rapid response to imatinib.

Here, we present a rare case of myeloproliferative neoplasms (MPN) with eosinophilia harboring both BCR::ABL1 and PDGFRB rearrangements, posing a classification dilemma. The patient exhibited clinical and laboratory features suggestive of chronic myeloid leukemia (CML) and myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK), highlighting the diagnostic challenges associated with overlapping phenotypes. Despite the complexity, imatinib treatment swiftly achieved deep molecular remission, underscoring the therapeutic efficacy of tyrosine kinase inhibitors in such scenarios. Furthermore, the rapid attainment of deep remission by this patient in response to imatinib closely resembles that observed in MLN-TK patients with PDGFRB rearrangements. Further research is warranted to elucidate the underlying mechanisms driving the coexistence of multiple oncogenic rearrangements in MPNs and to optimize therapeutic strategies for these complex cases.

Oral Decitabine/Cedazuridine Is an Effective Ambulatory Therapy for Patients With Myelofibrosis Refractory to JAK2 Inhibitor Therapy.

BACKGROUND: Outcomes are dismal for patients with myelofibrosis (MF) who are no longer responsive to JAK2 inhibitors (JAKi) and/or have increasing blast cell numbers. Although prior reports have suggested the benefits of intravenous decitabine (DAC) combined with ruxolitinib for patients with Myeloproliferative Neoplasm (MPN) accelerated/blast phase (AP/BP), decitabine-cedazuridine (DEC-C), an oral fixed-dose combination providing equivalent pharmacokinetic exposure, has not been evaluated in MF. METHODS: We conducted a retrospective analysis of 14 patients with high-risk MF refractory to ruxolitinib or MPN-AP (10-19% blasts) treated with DEC-C +/- JAKi at Mount Sinai Hospital from 2021 to 2024. RESULTS: The cohort was elderly (median age,76 years) and almost uniformly possessed high risk mutations with 13 of the 14 patients progressing on JAKi therapy. With a median follow-up of 9.4 months, the median overall survival (OS) was 29 months for the entire cohort. Median OS was 10.8 months for MPN-AP and was not reached for ruxolitinib refractory MF patients. All patients (n = 9) receiving > 4 cycles of DEC-C had clinical benefit exemplified by a reduction in blast cell numbers, spleen size, and lack of progression to MPN-BP (78%). Furthermore, 3/14 patients proceeded to allogeneic stem cell transplant. Myelosuppression was a common adverse event which was managed by reducing the number of days of administration of DEC-C from 5 to 3 per cycle. CONCLUSIONS: This report demonstrates the feasibility, tolerability, and clinical benefit of an exclusively ambulatory regimen for high-risk, elderly patients with advanced MF which warrants further evaluation in a prospective clinical trial.