International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: integrating morphologic, clinical, and genomic data.

The classification of myeloid neoplasms and acute leukemias was last updated in 2016 within a collaboration between the World Health Organization (WHO), the Society for Hematopathology, and the European Association for Haematopathology. This collaboration was primarily based on input from a clinical advisory committees (CACs) composed of pathologists, hematologists, oncologists, geneticists, and bioinformaticians from around the world. The recent advances in our understanding of the biology of hematologic malignancies, the experience with the use of the 2016 WHO classification in clinical practice, and the results of clinical trials have indicated the need for further revising and updating the classification. As a continuation of this CAC-based process, the authors, a group with expertise in the clinical, pathologic, and genetic aspects of these disorders, developed the International Consensus Classification (ICC) of myeloid neoplasms and acute leukemias. Using a multiparameter approach, the main objective of the consensus process was the definition of real disease entities, including the introduction of new entities and refined criteria for existing diagnostic categories, based on accumulated data. The ICC is aimed at facilitating diagnosis and prognostication of these neoplasms, improving treatment of affected patients, and allowing the design of innovative clinical trials.

Splenic irradiation for myelofibrosis prior to hematopoietic cell transplantation: A global collaborative analysis.

Splenomegaly is the clinical hallmark of myelofibrosis. Splenomegaly at the time of allogeneic hematopoietic cell transplantation (HCT) is associated with graft failure and poor graft function. Strategies to reduce spleen size before HCT especially after failure to Janus kinase (JAK) inhibition represent unmet clinical needs in the field. Here, we leveraged a global collaboration to investigate the safety and efficacy of splenic irradiation as part of the HCT platform for patients with myelofibrosis. We included 59 patients, receiving irradiation within a median of 2 weeks (range, 0.9-12 weeks) before HCT. Overall, the median spleen size prior to irradiation was 23 cm (range, 14-35). Splenic irradiation resulted in a significant and rapid spleen size reduction in 97% of patients (57/59), with a median decrease of 5.0 cm (95% confidence interval, 4.1-6.3 cm). The most frequent adverse event was thrombocytopenia, with no correlation between irradiation dose and hematological toxicities. The 3-year overall survival was 62% (95% CI, 48%-76%) and 1-year non-relapse mortality was 26% (95% CI, 14%-38%). Independent predictors for survival were severe thrombocytopenia and anemia before irradiation, transplant-specific risk score, higher-intensity conditioning, and present portal vein thrombosis. When using a propensity score matching adjusted for common confounders, splenic irradiation was associated with significantly reduced relapse (p = .01), showing a 3-year incidence of 12% for splenic irradiation versus 29% for patients with immediate HCT and 38% for patients receiving splenectomy. In conclusion, splenic irradiation immediately before HCT is a reasonable approach in patients experiencing JAK inhibition failure and is associated with a low incidence of relapse.

Incidence of bleeding events in patients on concomitant tyrosine kinase inhibitors and selective serotonin reuptake inhibitors.

INTRODUCTION: In this study, we aim to determine the risk of bleeding or thrombosis with concurrent use of tyrosine kinase inhibitors (TKIs) used to treat CML, and serotonin reuptake inhibitors (SSRIs). METHODS: We conducted a retrospective cohort study of patients with CP-CML cared for at Massachusetts General Hospital (MGH) between April 2016 to February 2021. Participants were included if diagnosed with CP-CML and began TKI treatment (imatinib, dasatinib, nilotinib, bosutinib, or ponatinib) after April 2016. RESULTS: One hundred patients were evaluated, eighty of whom were taking TKIs only (median age 55, 40% female), and twenty were taking TKI and SSRI concomitantly (median age 53.5, 55% female). Baseline demographics between these groups were similar across all variables. Patients in the TKI only group had 9 bleeding events and 3 thrombotic events. Patients in the combination group had 6 bleeding events and 1 thrombotic event. There was no difference between overall rates of major bleeding (4% v. 10%, p = 0.26) or thrombotic events (4% v. 5%, p = 1). However, patients in the combination group were more likely to have major intracranial bleeding events (0% v. 10%, p = 0.04), and there was a trend to significance for minor bleeding events (7.5% v. 20%, p = 0.11). CONCLUSIONS: Concomitant use of TKIs and SSRIs does not appear to increase the total risk of bleeding or thrombotic events compared to patients on TKIs only. However, concomitant use of TKIs and SSRIs may increase risk of intracranial bleeding. Further work is needed to fully assess this risk.

Chemotherapy Resistance in B-ALL with Cryptic NUP214-ABL1 Is Amenable to Kinase Inhibition and Immunotherapy.

BCR-ABL1 kinase inhibitors have improved the prognosis of Philadelphia-chromosome-positive (Ph+)-acute lymphoblastic leukemia (ALL). Ph-like (or BCR-ABL1-like) ALL does not express BCR-ABL1 but commonly harbors other genomic alterations of signaling molecules that may be amenable to therapy. Here, we report a case with a NUP214-ABL1 fusion detected at relapse by multiplexed, targeted RNA sequencing. It had escaped conventional molecular work-up at diagnosis, including cytogenetic analysis and fluorescence in situ hybridization for ABL1 rearrangements. The patient had responded poorly to initial multi-agent chemotherapy and inotuzumab immunotherapy at relapse before the fusion was revealed. The addition of dasatinib targeting NUP214-ABL1 to inotuzumab resulted in complete molecular remission, but recurrence occurred rapidly with dasatinib alone. However, deep molecular remission was recaptured with a combination of blinatumomab and ponatinib, so he could proceed to allotransplantation. This case illustrates that next-generation sequencing approaches designed to discover cryptic gene fusions can benefit patients with Ph-like ALL.

Implementation and Clinical Adoption of Precision Oncology Workflows Across a Healthcare Network.

BACKGROUND: Precision oncology relies on molecular diagnostics, and the value-proposition of modern healthcare networks promises a higher standard of care across partner sites. We present the results of a clinical pilot to standardize precision oncology workflows. METHODS: Workflows are defined as the development, roll-out, and updating of disease-specific molecular order sets. We tracked the timeline, composition, and effort of consensus meetings to define the combination of molecular tests. To assess clinical impact, we examined order set adoption over a two-year period (before and after roll-out) across all gastrointestinal and hepatopancreatobiliary (GI) malignancies, and by provider location within the network. RESULTS: Development of 12 disease center-specific order sets took ~9 months, and the average number of tests per indication changed from 2.9 to 2.8 (P = .74). After roll-out, we identified significant increases in requests for GI patients (17%; P < .001), compliance with testing recommendations (9%; P < .001), and the fraction of "abnormal" results (6%; P < .001). Of 1088 GI patients, only 3 received targeted agents based on findings derived from non-recommended orders (1 before and 2 after roll-out); indicating that our practice did not negatively affect patient treatments. Preliminary analysis showed 99% compliance by providers in network sites, confirming the adoption of the order sets across the network. CONCLUSION: Our study details the effort of establishing precision oncology workflows, the adoption pattern, and the absence of harm from the reduction of non-recommended orders. Establishing a modifiable communication tool for molecular testing is an essential component to optimize patient care via precision oncology.

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

Posttraumatic stress disorder symptoms in patients with acute myeloid leukemia.

BACKGROUND: Patients with acute myeloid leukemia (AML) receiving intensive chemotherapy face a life-threatening illness, isolating hospitalization, and substantial physical and psychological symptoms. However, data are limited regarding risk factors of posttraumatic stress disorder (PTSD) symptoms in this population. METHODS: The authors conducted a secondary analysis of data from 160 patients with high-risk AML who were enrolled in a supportive care trial. The PTSD Checklist-Civilian Version was used to assess PTSD symptoms at 1 month after AML diagnosis. The Brief COPE and the Functional Assessment of Cancer Therapy-Leukemia were to assess coping and quality of life (QOL), respectively. In addition, multivariate regression models were constructed to assess the relation between PTSD symptoms and baseline sociodemographic factors, coping, and QOL. RESULTS: Twenty-eight percent of patients reported PTSD symptoms, describing high rates of intrusion, avoidance, and hypervigiliance. Baseline sociodemographic factors significantly associated with PTSD symptoms were age (B = -0.26; P = .002), race (B = -8.78; P = .004), and postgraduate education (B = -6.30; P = .029). Higher baseline QOL (B = -0.37; P ≤ .001) and less decline in QOL during hospitalization (B = -0.05; P = .224) were associated with fewer PTSD symptoms. Approach-oriented coping (B = -0.92; P = .001) was associated with fewer PTSD symptoms, whereas avoidant coping (B = 2.42; P ≤ .001) was associated with higher PTSD symptoms. CONCLUSIONS: A substantial proportion of patients with AML report clinically significant PTSD symptoms 1 month after initiating intensive chemotherapy. Patients' baseline QOL, coping strategies, and extent of QOL decline during hospitalization emerge as important risk factors for PTSD, underscoring the need for supportive oncology interventions to reduce the risk of PTSD in this population.

Hypoxemic Respiratory Failure Following Ruxolitinib Discontinuation in Allogeneic Hematopoietic Cell Transplantation Recipients.

Ruxolitinib, a selective inhibitor of Janus kinases 1 and 2, is increasingly being used in allogeneic hematopoietic cell transplantation (HCT) recipients following its approval by the U.S. Food and Drug Administration for the treatment of steroid-refractory acute graft-versus-host disease. Although there is extensive experience using ruxolitinib for patients with myeloproliferative neoplasms, the biologic effects and clinical implications of its dosing, tapering, and discontinuation for allogeneic HCT recipients are incompletely characterized. We describe three allogeneic HCT recipients who developed acute hypoxemic respiratory failure within 3 months of ruxolitinib discontinuation. Radiographic findings included marked bilateral ground-glass opacities. Systemic corticosteroids and reinitiation of ruxolitinib resulted in rapid clinical improvement in all three patients. All three patients achieved a significant clinical response, with decrease in oxygen requirement and improvement in radiographic changes. Given the increasing use of ruxolitinib in allogeneic HCT recipients, there is significant impetus to characterize the biologic and clinical effects resulting from discontinuation of ruxolitinib, to better tailor treatment plans and prevent potential adverse effects.

Mutant calreticulin in myeloproliferative neoplasms.

Recurrent mutations in calreticulin are present in ∼20% of patients with myeloproliferative neoplasms (MPNs). Since its discovery in 2013, we now have a more precise understanding of how mutant CALR, an endoplasmic reticulum chaperone protein, activates the JAK/STAT signaling pathway via a pathogenic binding interaction with the thrombopoietin receptor MPL to induce MPNs. In this Spotlight article, we review the current understanding of the biology underpinning mutant CALR-driven MPNs, discuss clinical implications, and highlight future therapeutic approaches.

A Practical Guide for Using Myelofibrosis Prognostic Models in the Clinic.

Primary myelofibrosis (PMF) has the least favorable prognosis of the Philadelphia chromosome-negative myeloproliferative neoplasms, which also include essential thrombocythemia (ET) and polycythemia vera (PV). However, clinical presentations and outcomes of PMF vary widely, with median overall survival ranging from years to decades. Given the heterogeneity of PMF, there has been considerable effort to develop discriminatory prognostic models to help with management decisions, particularly for the consideration of hematopoietic stem cell transplantation in patients at higher risk. Although earlier models incorporated only clinical features in risk stratification, contemporary models increasingly use molecular and cytogenetic features, leading to more comprehensive prognostication. This article reviews the most widely adopted prognostic models used for PMF, including the International Prognostic Scoring System (IPSS), dynamic IPSS (DIPSS)/DIPSS+, mutation-enhanced IPSS for transplant-age patients (MIPSS70)/MIPSS70+/MIPSS70+ version 2.0, genetically inspired prognostic scoring system, and Myelofibrosis Secondary to PV and ET-Prognostic Model in patients with post-ET/PV myelofibrosis. We also discuss newly emerging prognostic models and provide a practical approach to risk stratification in patients with PMF and post-ET/PV myelofibrosis.

Outcomes for older adults with acute myeloid leukemia after an intensive care unit admission.

BACKGROUND: Older adults with acute myeloid leukemia (AML) are often assumed to have poor outcomes after admission to the intensive care unit (ICU). However, little is known about ICU utilization and post-ICU outcomes in this population. METHODS: The authors conducted a retrospective analysis for 330 patients who were 60 years old or older and were diagnosed with AML between 2005 and 2013 at 2 hospitals in Boston.They used descriptive statistics to examine the proportion of patients admitted to the ICU as well as their mortality and functional recovery. They used logistic regression to identify risk factors for in-hospital mortality. RESULTS: Ninety-six patients (29%) were admitted to the ICU, primarily because of respiratory failure (39%), septic shock (28%), and neurological compromise (9%). The proportions of patients who survived to hospital discharge, 90 days, and 1 year were 47% (45 of 96), 35% (34 of 96), and 30% (29 of 96), respectively. At 90 days, 76% of the patients had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1, and 86% were in complete remission (CR) and/or continued to receive AML-directed therapy. In a multivariate analysis, a poorer baseline ECOG PS score (odds ratio, 2.76; P = .013) and the need for 2 or more life-sustaining therapies (ie, vasopressors, invasive ventilation, and/or renal replacement therapy; odds ratio, 12.4; P < .001) were associated with increased odds of in-hospital mortality. CONCLUSIONS: Although almost one-third of older patients with AML are admitted to an ICU, nearly half survive to hospital discharge with good functional outcomes. The baseline performance status and the need for 2 or more life-sustaining therapies predict hospital mortality. These data support the judicious use of ICU resources for older patients with AML.

Isocitrate dehydrogenase 1 and 2 mutations, 2-hydroxyglutarate levels, and response to standard chemotherapy for patients with newly diagnosed acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) cells harboring mutations in isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) produce the oncometabolite 2-hydroxyglutarate (2HG). This study prospectively evaluated the 2HG levels, IDH1/2 mutational status, and outcomes of patients receiving standard chemotherapy for newly diagnosed AML. METHODS: Serial samples of serum, urine, and bone marrow aspirates were collected from patients newly diagnosed with AML, and 2HG levels were measured with mass spectrometry. Patients with baseline serum 2HG levels greater than 1000 ng/mL or marrow pellet 2HG levels greater than 1000 ng/2 × 106 cells, which suggested the presence of an IDH1/2 mutation, underwent serial testing. IDH1/2 mutations and estimated variant allele frequencies were identified. AML characteristics were compared with the Wilcoxon test and Fisher's exact test. Disease-free survival and overall survival (OS) were evaluated with log-rank tests and Cox regression. RESULTS: Two hundred and two patients were treated for AML; 51 harbored IDH1/2 mutations. IDH1/2-mutated patients had significantly higher 2HG levels in serum, urine, bone marrow aspirates, and aspirate cell pellets than wild-type patients. A serum 2HG level greater than 534.5 ng/mL was 98.8% specific for the presence of an IDH1/2 mutation. Patients with IDH1/2-mutated AML treated with 7+3-based induction had a 2-year event-free survival (EFS) rate of 44% and a 2-year OS rate of 57%. There was no difference in complete remission rates, EFS, or OS between IDH1/2-mutated and wild-type patients. Decreased serum 2HG levels on day 14 as a proportion of the baseline were significantly associated with improvements in EFS (P = .047) and OS (P = .019) in a multivariate analysis. CONCLUSIONS: Among patients with IDH1/2-mutated AML, 2HG levels are highly specific for the mutational status at diagnosis, and they have prognostic relevance in patients receiving standard chemotherapy.

A phase I study of lenalidomide plus chemotherapy with mitoxantrone, etoposide, and cytarabine for the reinduction of patients with acute myeloid leukemia.

Patients with relapsed AML have a poor prognosis and limited responses to standard chemotherapy. Lenalidomide is an immunomodulatory drug that may modulate anti-tumor immunity. We performed a study to evaluate the safety and tolerability of lenalidomide with mitoxantrone, etoposide and cytarabine (MEC) in relapsed/refractory AML. Adult patients with relapsed/refractory AML were eligible for this phase I dose-escalation study. We enrolled 35 patients using a "3 + 3" design, with a 10 patient expansion cohort at the maximum tolerated dose (MTD). Lenalidomide was initially given days 1-14 and MEC days 4-8; due to delayed count recovery, the protocol was amended to administer lenalidomide days 1-10. The dose of lenalidomide was then escalated starting at 5 mg/d (5-10-25-50). The primary objective was tolerability and MTD determination, with secondary outcomes including overall survival (OS). The MTD of lenalidomide combined with MEC was 50 mg/d days 1-10. Among the 35 enrolled patients, 12 achieved complete remission (CR) (34%, 90%CI 21-50%); 30-day mortality was 6% and 60-day mortality 13%. The median OS for all patients was 11.5 months. Among 17 patients treated at the MTD, 7 attained CR (41%); the median OS was not reached while 12-month OS was 61%. Following therapy with MEC and lenalidomide, patient CD4+ and CD8+ T-cells demonstrated increased inflammatory responses to autologous tumor lysate. The combination of MEC and lenalidomide is tolerable with an RP2D of lenalidomide 50 mg/d days 1-10, yielding encouraging response rates. Further studies are planned to explore the potential immunomodulatory effect of lenalidomide and MEC.

Association between insurance status at diagnosis and overall survival in chronic myeloid leukemia: A population-based study.

BACKGROUND: Chronic myeloid leukemia (CML) can be treated effectively with tyrosine kinase inhibitor therapy directed at BCR-ABL, but access to care, medication cost, and adherence may be barriers to treatment. This study was designed to determine whether the insurance status at diagnosis influences CML patient outcomes. METHODS: The Surveillance, Epidemiology, and End Results database was used to identify 5784 patients, aged 15 years or older, who were diagnosed with CML between 2007 and 2012 and whose insurance status was documented at diagnosis. The primary outcome was 5-year overall survival (OS). Covariates of interest included the age at diagnosis, race, ethnicity, sex, county-level socioeconomic status, and marital status. OS was evaluated with a log-rank test and Kaplan-Meier estimates. RESULTS: Among patients aged 15 to 64 years, insurance status was associated with OS (P < .001): being uninsured or having Medicaid was associated with worse 5-year OS in comparison with being insured (uninsured patients, 72.7%; Medicaid patients, 73.1%; insured patients, 86.6%). For patients who were 65 years old or older, insurance had less of an impact on OS (P = .07), with similar 5-year OS rates for patients with Medicaid and those with other insurance (40.2% vs 43.4%). In a multivariate analysis of patients aged 15 to 64 years, both uninsured patients (hazard ratio [HR], 1.93; P < .001) and Medicaid patients (HR, 1.83; P < .001) had an increased hazard of death in comparison with insured patients; patients younger than 40 years, female patients, and married patients also had a lower hazard of death. CONCLUSION: These findings suggest that CML patients under the age of 65 years who are uninsured or have Medicaid have significantly worse survival than patients with other insurance coverage. Cancer 2017;123:2561-69. © 2017 American Cancer Society.

Clinical and molecular genetic characterization of myelofibrosis.

PURPOSE OF REVIEW: The myeloproliferative neoplasms include polycythemia vera, essential thrombocythemia, and myelofibrosis. Of these, myelofibrosis often has the most aggressive course. There is, however, often significant clinical heterogeneity among patients with myelofibrosis. We seek to summarize recent clinical and biological findings in myelofibrosis as well as review the spectrum of clinically relevant mutation in myelofibrosis and their implications. RECENT FINDINGS: The mutational spectrum in myelofibrosis includes driver mutations in genes such as JAK2, calreticulin, and myeloproliferative leukemia virus oncogene. In addition, recurrent mutations in epigenetic modifiers such as ASXL1 and TET2 have also been described. Importantly, several studies have indicated that specific mutations, as well as the number of mutations, that a patient bears may have important clinical consequences. The presence or absence of certain mutations may help to determine a patient's risk for thrombosis, leukemic transformation, and survival. SUMMARY: Myelofibrosis often has variable outcomes among patients. Prognostic systems based on clinical observations have been developed in an attempt to predict risks of disease progression and transformation. The discovery of recurrent genomic alterations in myelofibrosis, and the observation that many of these alterations may help predict clinical outcomes, has heralded a new era in the biologic understanding and clinical approach to myelofibrosis.

The role of families in decisions regarding cancer treatments.

BACKGROUND: Shared decision-making is an important component of patient-centered care and is associated with improved outcomes. To the authors' knowledge, little is known concerning the extent and predictors of the involvement of a patient's family in decisions regarding cancer treatments. METHODS: The Cancer Care Outcomes Research and Surveillance (CanCORS) Consortium is a large, multiregional, prospective cohort study of the cancer care and outcomes of patients with lung and colorectal cancer. Participants reported the roles of their families in decision-making regarding treatment. Multinomial logistic regression was used to assess patient factors associated with family roles in decisions. RESULTS: Among 5284 patients, 80 (1.5%) reported family-controlled decisions, with the highest adjusted rates (12.8%) noted among non-English-speaking Asians. Among the 5204 remaining patients, 49.4% reported equally sharing decisions with family, 22.1% reported some family input, and 28.5% reported little family input. In adjusted analyses, patients who were married, female, older, and insured more often reported equally shared decisions with family (all P <.001). Adjusted family involvement varied by race/ethnicity and language, with Chinese-speaking Asian (59.8%) and Spanish-speaking Hispanic (54.8%) patients equally sharing decisions with family more often than white individuals (47.6%). Veterans Affairs patients were least likely to report sharing decisions with family, even after adjustment for marital status and social support (P <.001). CONCLUSIONS: The majority of patients with newly diagnosed lung or colorectal cancer involve family members in treatment decisions. Non-English-speaking Asians and Hispanics rely significantly on family. Further studies are needed to determine the impact of family involvement in treatment decisions on outcomes; until then, physicians should consider eliciting patients' preferences for family involvement.

Consensus recommendations on peripheral blood smear review: defining curricular standards and fellow competency.

Graduate medical education training in hematology in North America is accredited by the Accreditation Council for Graduate Medical Education (ACGME). Trainees routinely review peripheral blood smears (PBS) in providing clinical care. Competency in PBS review at graduation is required by the ACGME. However, there are no consensus guidelines on best practices surrounding PBS review, education, or competency. We describe the generation of proposed theory and the consensus recommendations developed through a multi-institutional focus group, developed using constructivist grounded theory and a modified nominal group technique. Eight academic hematologists, spanning classical and malignant hematology, enrolled and participated in 2 one-hour focus groups. All routinely worked with fellows and half had formally instructed trainees on PBS interpretation. Focus group data were analyzed using mixed-methods techniques. Tenets of emerging theory were identified through inductive coding. Consensus recommendations (CR) were generated. Participants reviewed CR in an iterative fashion until consensus was reached. Strong consensus was reached on multiple aspects of PBS education. All agreed that trainees should learn PBS review through a systematic approach. Group discussion focused on disorders of red and white blood cells. The diagnoses of acute leukemia and thrombotic microangiopathies were most commonly discussed, with specific emphasis on disorders in which prompt recognition was required to avert significant patient morbidity. These CR offer external validity to future research and curricular development for both PBS review and other visuospatial tasks in medical education.

Transcriptional differences between JAK2-V617F and wild-type bone marrow cells in patients with myeloproliferative neoplasms.

The JAK2-V617F mutation is the most common cause of myeloproliferative neoplasms. Although experiments have revealed that this gain-of-function mutation is associated with myeloid blood cell expansion and increased production of white cells, red cells, and platelets, the transcriptional consequences of the JAK2-V617F mutation in different cellular compartments of the bone marrow have not yet been fully elucidated. To study the direct effects of JAK2-V617F on bone marrow cells in patients with myeloproliferative neoplasms, we performed joint single-cell RNA sequencing and JAK2 genotyping on CD34+-enriched cells from eight patients with newly diagnosed essential thrombocythemia or polycythemia vera. We found that the JAK2-V617F mutation increases the expression of interferon-response genes (e.g., HLAs) and the leptin receptor in hematopoietic progenitor cells. Furthermore, we sequenced a population of CD34- bone marrow monocytes and found that the JAK2 mutation increased expression of intermediate monocyte genes and the fibrocyte-associated surface protein SLAMF7 in these cells.