Proposed diagnostic criteria for classical chronic myelomonocytic leukemia (CMML), CMML variants and pre-CMML conditions

Waldenström Macroglobulinemia and Chronic Myelomonocytic Leukemia: Case Report and Literature Review

As hematological tumor patients are surviving long-term, the long-term toxicities of therapeutic regimens have become increasingly evident. The coexistence of two hematological tumors in the same patient is extremely rare and typically shows an aggressive clinical course and unsatisfactory prognosis. In the present case, we describe the case of a 64-year-old man who was admitted to the hospital because of fatigue. Biochemical showed an elevated monoclonal immunoglobulin M (IgM) at 37g/L. Next Generation Sequencing (NGS) analysis revealed MYD88L265p mutation, CXCR4 wild type. In August 2020, he was diagnosed with Waldenström macroglobulinemia (WM) and underwent six cycles of chemotherapy with bendamustine, zanubrutinib, and rituximab. However, he was admitted to the hospital in December 2022 following six-month history of Leukocytosis. Bone marrow (BM) flow cytometry (FCM) showed increased MO1 monocytes. Molecular studies were positive for TET2 mutations. He was finally diagnosed with WM and chronic myelomonocytic leukemia (CMML). Then he accepted hematopoietic stem cell transplantation (HSCT). Unfortunately, after 6 months, the patient died as a consequence of severe pulmonary infection.

An integrative multiparametric approach stratifies putative distinct phenotypes of blast phase chronic myelomonocytic leukemia

Approximately 30% of patients with chronic myelomonocytic leukemia (CMML) undergo transformation to a chemo-refractory blastic phase (BP-CMML). Seeking novel therapeutic approaches, we profiled blast transcriptomes from 42 BP-CMMLs, observing extensive transcriptional heterogeneity and poor alignment to current acute myeloid leukemia (AML) classifications. BP-CMMLs display distinctive transcriptomic profiles, including enrichment for quiescence and variability in drug response signatures. Integrating clinical, immunophenotype, and transcriptome parameters, Random Forest unsupervised clustering distinguishes immature and mature subtypes characterized by differential expression of transcriptional modules, oncogenes, apoptotic regulators, and patterns of surface marker expression. Subtypes differ in predicted response to AML drugs, validated ex vivo in primary samples. Iteratively refined stratification resolves a classification structure comprising five subtypes along a maturation spectrum, predictive of response to novel agents including consistent patterns for receptor tyrosine kinase (RTK), cyclin-dependent kinase (CDK), mechanistic target of rapamycin (MTOR), and mitogen-activated protein kinase (MAPK) inhibitors. Finally, we generate a prototype decision tree to stratify BP-CMML with high specificity and sensitivity, requiring validation but with potential clinical applicability to guide personalized drug selection for improved outcomes.

Advancements in the Application of scRNA-Seq in Breast Research: A Review

Single-cell sequencing technology provides apparent advantages in cell population heterogeneity, allowing individuals to better comprehend tissues and organs. Sequencing technology is currently moving beyond the standard transcriptome to the single-cell level, which is likely to bring new insights into the function of breast cells. In this study, we examine the primary cell types involved in breast development, as well as achievements in the study of scRNA-seq in the microenvironment, stressing the finding of novel cell subsets using single-cell approaches and analyzing the problems and solutions to scRNA-seq. Furthermore, we are excited about the field's promising future.

Predicting which subsets of patients with myelodysplastic neoplasms are more likely to progress to overt chronic myelomonocytic leukemia

The boundary between myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) has been revised in the latest World Health Organization classification of myeloid malignancies. These changes were motivated by the description of a subgroup of MDS patients identified as oligomonocytic chronic myelomonocytic leukemia (OM-CMML) at risk of evolving into overt CMML. Various studies will be reviewed describing the clinical and biological features of MDS patients evolving to CMML. The efforts to discover biomarkers enabling the identification of these patients at the time of MDS diagnosis will be discussed. Finally, the molecular landscape of these patients will be presented with a specific focus on the biallelic inactivation of TET2 in light of its functional impact on hematopoietic stem cells, granule-monocytic differentiation, and its tight interplay with inflammation.

Survival Outcomes of U.S. Patients with CMML: A Two-Decade Analysis from the SEER Database

Background: Chronic Myelomonocytic Leukemia (CMML) is a rare and aggressive form of leukemia with characteristics of both myeloproliferative neoplasms (MPNs) and myelodysplastic syndromes (MDSs). This study aims to explore the clinical features, survival outcomes, and prognostic factors in CMML patients over the past 20 years using a large sample. Methods: The study data from 4124 patients diagnosed with CMML between 2000 and 2017 were sourced from the SEER database. Demographic and clinical characteristics, along with overall and cancer-specific mortality, were examined. Factors with a p-value < 0.01 in univariate Cox regression were included in the multivariate Cox model to identify independent prognostic factors, with hazard ratios (HRs) greater than one indicating adverse outcomes. Results: The majority of the cohort were male (61.57%), and most diagnoses occurred between ages 60-79 (55.16%), with a small percentage under 40 (1.41%). Non-Hispanic whites represented the largest racial group (79.03%). Multivariate analysis showed higher mortality in males, those aged 80+, residents in metropolitan areas with populations between 250,000 and 1 million, single or widowed individuals, and those who underwent chemotherapy. Conversely, lower mortality was associated with an annual income of $75,000+. Conclusions: CMML remains a rare and highly aggressive hematologic disorder. This U.S.-based retrospective cohort study identified male gender, advanced age, single or widowed status, and chemotherapy as independent poor prognostic factors. While it is expected that older patients and those requiring chemotherapy would have a poorer prognosis, the higher mortality risk in single or widowed patients, as well as males, warrants further investigation. The early involvement of family and community support may help reduce mortality in these groups, suggesting a need for larger prospective studies to explore these associations further.

Immunophenotyping myelodysplastic neoplasms: the role of flow cytometry in the molecular classification era

The unique heterogenous landscape of myelodysplastic syndromes/neoplasms (MDS) has resulted in continuous redefinition of disease sub-entities, in view of the novel translational research data that have clarified several areas of the pathogenesis and the progression of the disease. The new international classifications (WHO 2022, ICC 2022) have incorporated genomic data defining phenotypical alterations, that guide clinical management of specific patient subgroups. On the other hand, for over a decade, multiparameter flow cytometry (MFC) has proven its value as a complementary diagnostic tool for these diseases and although it has never been established as a mandatory test for the baseline evaluation of MDS patients in international guidelines, it is almost universally adopted in everyday clinical practice for the assessment of suspected cytopenias through simplified scoring systems or elaborate analytical strategies for the detection of immunophenotypical dysplastic features in every hematopoietic cell lineage in the bone marrow (BM). In this review, we explore the clinically meaningful interplay of MFC data and genetic profiles of MDS patients, to reveal the currently existing and the potential future role of each methodology for routine clinical practice, and the benefit of the patients. We reviewed the existing knowledge and recent advances in the field and discuss how an integrated approach could lead to patient re-stratification and guide personalized management.

Phase I/II study of the clinical activity and safety of GSK3326595 in patients with myeloid neoplasms

Background

GSK3326595 is a potent, selective, reversible protein arginine methyltransferase 5 (PRMT5) inhibitor under investigation for treatment of myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML). In preclinical models of AML, PRMT5 inhibition decreased proliferation and increased cell death, supporting additional clinical research in myeloid neoplasms.

Objectives

To determine the clinical activity, safety, tolerability, dosing, additional measures of clinical activity, pharmacokinetics, and pharmacodynamics of GSK3326595.

Design

In part 1 of this open-label, multicenter, multipart, phase I/II study, adults with relapsed/refractory myeloid neoplasms (e.g., MDS, CMML, and AML) received monotherapy with 400 or 300 mg oral GSK3326595 once daily. Study termination occurred prior to part 2 enrollment.

Methods

Clinical activity was determined by the clinical benefit rate (CBR; proportion of patients achieving complete remission (CR), complete marrow remission (mCR), partial remission, stable disease (SD) >8 weeks, or hematologic improvement). Adverse events (AEs) were assessed by incidence and severity. Exploratory examination of spliceosome mutations was performed to determine the relationship between genomic profiles and clinical response to GSK3326595.

Results

Thirty patients with a median age of 73.5 years (range, 47-90) were enrolled; 13 (43%) and 17 (57%) received 400 and 300 mg of GSK3326595, respectively. Five (17%) patients met CBR criteria: 4 (13%) with SD >8 weeks and 1 (3%) achieving mCR. Of five patients with clinical benefit: three had SRSF2 mutation, one U2AF1, and one was splicing factor wild-type. Frequent GSK3326595-related AEs were decreased platelet count (27%), dysgeusia (23%), fatigue (20%), and nausea (20%). GSK3326595 had rapid absorption, with a T max of approximately 2 h and a terminal half-life of 4-6 h.

Conclusion

GSK3326595 monotherapy had limited clinical activity in heavily pretreated patients despite robust target engagement. The safety profile was broadly consistent with other published PRMT5 inhibitor studies.

Trial registration

ClinicalTrials.gov: NCT03614728.

Performance Evaluation of a Novel Artificial Intelligence-Assisted Digital Microscopy System for the Routine Analysis of Bone Marrow Aspirates

Bone marrow aspiration (BMA) smear analysis is essential for diagnosis, treatment, and monitoring of a variety of benign and neoplastic hematological conditions. Currently, this analysis is performed by manual microscopy. We conducted a multicenter study to validate a computational microscopy approach with an artificial intelligence-driven decision support system. A total of 795 BMA specimens (615 Romanowsky-stained and 180 Prussian blue-stained) from patients with neoplastic and other clinical conditions were analyzed, comparing the performance of the Scopio Labs X100 Full Field BMA system (test method) with manual microscopy (reference method). The system provided an average of 1,385 ± 536 (range, 0-3,131) cells per specimen for analysis. An average of 39.98 ± 19.64 fields of view (range, 0-140) per specimen were selected by the system for analysis, of them 87% ± 21% (range, 0%-100%) were accepted by the qualified operators. These regions were included in an average of 17.62 ± 7.24 regions of interest (range, 1-50) per specimen. The efficiency, sensitivity, and specificity for primary and secondary marrow aspirate characteristics (maturation, morphology, and count assessment), as well as overall interuser agreement, were evaluated. The test method showed a high correlation with the reference method for comprehensive BMA evaluation, both on Romanowsky- (90.85% efficiency, 81.61% sensitivity, and 92.88% specificity) and Prussian blue-stained samples (90.0% efficiency, 81.94% sensitivity, and 93.38% specificity). The overall agreement between the test and reference methods for BMA assessment was 91.1%. For repeatability and reproducibility, all standard deviations and coefficients of variation values were below the predefined acceptance criteria both for discrete measurements (coefficient of variation below 20%) and differential measurements (SD below 5%). The high degree of correlation between the digital decision support system and manual microscopy demonstrates the potential of this system to provide a high-quality, accurate digital BMA analysis, expediting expert review and diagnosis of BMA specimens, with practical applications including remote BMA evaluation and possibly new opportunities for the research of normal and neoplastic hematopoiesis.

Chronic myelomonocytic leukemia primarily presenting as life-threatening pericardial effusion, Eldoret, Kenya: A case report

Key Clinical Message

Chronic myelomonocytic leukemia, a rare case of hematological malignancy mainly affects the elderly and may present with life threatening pericardial effusion as an initial manifestation. High index of suspicion is hence key for early management.

Abstract

We present a case of an 81-year-old African male who presented with progressive cough, respiratory distress and bilateral lower limb swelling, and was diagnosed with life-threatening pericardial effusion resulting from chronic myelomonocytic leukemia following complete blood count, peripheral blood film, bone marrow aspirate with trephine biopsy, and flow cytometry studies.

Management of adult patients with CMML undergoing allo-HCT: recommendations from the EBMT PH&G Committee

ABSTRACT

Chronic myelomonocytic leukemia (CMML) is a heterogeneous disease presenting with either myeloproliferative or myelodysplastic features. Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only potentially curative option, but the inherent toxicity of this procedure makes the decision to proceed to allo-HCT challenging, particularly because patients with CMML are mostly older and comorbid. Therefore, the decision between a nonintensive treatment approach and allo-HCT represents a delicate balance, especially because prospective randomized studies are lacking and retrospective data in the literature are conflicting. International consensus on the selection of patients and the ideal timing of allo-HCT, specifically in CMML, could not be reached in international recommendations published 6 years ago. Since then, new, CMML-specific data have been published. The European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines (PH&G) Committee assembled a panel of experts in the field to provide the first best practice recommendations on the role of allo-HCT specifically in CMML. Recommendations were based on the results of an international survey, a comprehensive review of the literature, and expert opinions on the subject, after structured discussion and circulation of recommendations. Algorithms for patient selection, timing of allo-HCT during the course of the disease, pretransplant strategies, allo-HCT modality, as well as posttransplant management for patients with CMML were outlined. The keynote message is, that once a patient has been identified as a transplant candidate, upfront transplantation without prior disease-modifying treatment is preferred to maximize chances of reaching allo-HCT whenever possible, irrespective of bone marrow blast counts.

Technical, gating and interpretation recommendations for the partitioning of circulating monocyte subsets assessed by flow cytometry

The monocyte subset partitioning by flow cytometry, known as "monocyte assay," is now integrated into the new classifications as a supporting criterion for CMML diagnosis, if a relative accumulation of classical monocytes above 94% of total circulating monocytes is observed. Here we provide clinical flow cytometry laboratories with technical support adapted for the most commonly used cytometers. Step-by-step explanations of the gating strategy developed on whole peripheral blood are presented while underlining the most common difficulties. In a second part, interpretation recommendations of circulating monocyte partitioning from the dedicated French working group "CytHem-LMMC" are shared as well as the main pitfalls, including false positive and false negative cases. The particular flow-defined inflammatory profile is described and the usefulness of the nonclassical monocyte specific marker, namely slan, highlighted. Examples of reporting to the physician with frequent situations encountered when using the monocyte assay are also presented.

Comparing malignant monocytosis across the updated WHO and ICC classifications of 2022

ABSTRACT

The World Health Organization (WHO) classification of hematolymphoid tumors and the International Consensus Classification (ICC) of 2022 introduced major changes to the definition of chronic myelomonocytic leukemia (CMML). To assess its qualitative and quantitative implications for patient care, we started with 3311 established CMML cases (according to WHO 2017 criteria) and included 2130 oligomonocytosis cases fulfilling the new CMML diagnostic criteria. Applying both 2022 classification systems, 356 and 241 of oligomonocytosis cases were newly classified as myelodysplastic (MD)-CMML (WHO and ICC 2022, respectively), most of which were diagnosed as myelodysplastic syndrome (MDS) according to the WHO 2017 classification. Importantly, 1.5 times more oligomonocytosis cases were classified as CMML according to WHO 2022 than based on ICC, because of different diagnostic criteria. Genetic analyses of the newly classified CMML cases showed a distinct mutational profile with strong enrichment of MDS-typical alterations, resulting in a transcriptional subgroup separated from established MD and myeloproliferative CMML. Despite a different cytogenetic, molecular, immunophenotypic, and transcriptional landscape, no differences in overall survival were found between newly classified and established MD-CMML cases. To the best of our knowledge, this study represents the most comprehensive analysis of routine CMML cases to date, both in terms of clinical characterization and transcriptomic analysis, placing newly classified CMML cases on a disease continuum between MDS and previously established CMML.

Characteristics and long-term outcome in a large series of chronic myelomonocytic leukaemia patients including 104 formerly referred to as oligomonocytic

Recently modified diagnostic criteria for chronic myelomonocytic leukaemia (CMML) have lowered the cut-off for absolute monocytosis. In the largest series to date, we have analysed 313 CMML patients, including 104 with oligomonocytic (OM)-CMML. Five-year survival was longer for OM-CMML than for other patients (p < 0.001). Multivariate analysis identified OM-CMML as a favourable prognostic factor (HR 0.58; p = 0.002). The 5-year cumulative incidence of progression to classical CMML was 47%. Older age and transfusion dependence were adverse prognostic factors for OM-CMML. Our results support the inclusion of OM-CMML in the CMML category as a subtype with superior outcomes.

Chronic Myelomonocytic Leukemia-Associated Immune Thrombocytopenic Purpura: A Report of a Rare Case and a Review of Literature

Chronic myelomonocytic leukemia (CMML) presents as a complex hematologic malignancy with myelodysplastic and myeloproliferative features. Our case report explores the rare coexistence of CMML with immune thrombocytopenic purpura (ITP) in a 63-year-old female patient. CMML diagnosis followed World Health Organization criteria, and the patient was classified as having high-risk myelodysplastic syndrome (MDS)-CMML stage 2. Initial treatment with subcutaneous azacytidine for CMML proved partially effective, highlighting persistent severe thrombocytopenia. Subsequent investigations revealed secondary ITP associated with Crohn's disease. Conventional ITP therapies, including high-dose steroids and intravenous immunoglobulin, showed limited efficacy. Eltrombopag, a thrombopoietin receptor agonist, was initiated, resulting in the normalization of platelet counts within six weeks. Our case emphasizes the diagnostic challenges and intricate treatment landscape of CMML-associated ITP, suggesting eltrombopag as a potential therapeutic option in refractory cases. The study contributes to the evolving understanding of the complex interplay between myeloid disorders and immune-mediated hematological conditions, calling for personalized and multidisciplinary approaches to enhance patient outcomes.

Kidney and Urinary Tract Involvement in Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy affecting the bone marrow and resulting in peripheral blood monocytosis. Kidney and urinary tract involvement is common and can present dramatically with life-threatening consequences. Kidney involvement can be the result of direct or indirect mechanisms, including prerenal azotemia, glomerular disease, tubulointerstitial involvement, and renovascular disorders. Urinary tract involvement, electrolyte and acid-base disorders, as well as nephrotoxicity from treatment of the disorder can also occur. Given this multifactorial pathogenesis involving several mechanisms concomitantly, nephrologists must exercise heightened awareness and maintain a low threshold for kidney biopsy. There is a pressing need for future research endeavors to elucidate and target the manifestations of CMML that involve the kidneys with the ultimate goal of augmenting overall prognosis and therapeutic outcomes.

A case of sudden hearing loss in a patient with chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia is a myeloid stem cell disease characterized by an abnormal production and accumulation of monocytic cells in association with other signs of myeloproliferation. Extramedullary manifestations of CMML are common and can affect the spleen, liver skin, and lymph nodes. However, otologic manifestations are extremely rare and could have occurred from either direct leukemic infiltration, hemorrhage of the cochlea, labyrinth, leukostasis, or infection. There is no standard treatment protocol for sensorineural hearing loss in CMML patients. More research is needed to improve the understanding of the pathogenesis of this condition, in order to provide better treatment options.

Germline CSF3R Variant in Chronic Myelomonocytic Leukemia: Linking Genetic Predisposition to Uncommon Hemorrhagic Symptoms

Chronic myelomonocytic leukemia (CMML) is a hematological neoplasm characterized by monocytosis, splenomegaly, thrombocytopenia, and anemia. Moreover, it is associated with SRSF2 mutations and, rarely, with CSF3R variants. We present the case of an 84-year-old patient with persistent anemia and monocytosis. Due to the presence of dysmorphic granulocytes, monocyte atypia, and myeloid precursors in the peripheral blood cells, the patient was subjected to a bone marrow examination. The diagnosis was consistent with CMML type 2. The Hemocoagulative test showed an increase in fibrinolysis markers. Next-generation targeted sequencing showed TET2 and SRSF2 mutations, along with an unexpected CSF3R germline missense variant, rarely encountered in CMML. The patient started Azacitidine treatment and achieved normal hemostatic process values. In conclusion, we identified a heterozygous germline mutation that, together with TET2 and SRSF2 variants, was responsible for the hemorrhagic manifestation.

Clinical characterization of the mutational landscape of 24,639 real-world samples from patients with myeloid malignancies

Myeloid neoplasms represent a broad spectrum of hematological disorders for which somatic mutation status in key driver genes is important for diagnosis, prognosis and treatment. Here we summarize the findings of a targeted, next generation sequencing laboratory developed test in 24,639 clinical myeloid samples. Data were analyzed comprehensively and as part of individual cohorts specific to acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and myeloproliferative neoplasms (MPN). Overall, 48,015 variants were detected, and variants were found in all 50 genes in the panel. The mean number of mutations per patient was 1.95. Mutation number increased with age (Spearman's rank correlation coefficient, ρ = 0.29, P < 0.0001) and was higher in patients with AML than MDS or MPN (Student's t-test, P < 0.0001). TET2 was the most common mutation detected (19.1% of samples; 4,695/24,639) including 7.7% (1,908/24,639) with multi-hit TET2 mutations. Mutation frequency was correlated between patients with cytopenias and MDS (Spearman's, ρ = 0.97, P < 2.2×10-16) with the MDS diagnostic gene SF3B1 being the only notable outlier. This large retrospective study shows the utility of NGS testing to inform clinical decisions during routine clinical care and highlights the mutational landscape of a broad population of myeloid patients.

[MDS & CMML: Diagnostic and classification]

In 2023, a diagnosis process of myelodysplastic syndrome (MDS) or chronic myelomonocytic leukemia (CMML) is mainly based on morphological results obtained on bone marrow and blood smears which could be completed by cytogenetical analyses. Due to recent finding, flow cytometry data are recognized as useful for the diagnosis of CMML especially. Actual classifications and prognostic scoring systems have changed and nowadays include results of high-throughput sequencing approaches in addition to cytogenetical results. All together, these data allow the medical world to correctly evaluate the prognosis of these patients and to provide some information for targeted therapies. This chapter will provide the most important modifications recently published in the field of diagnosis and prognosis of MDS and CMML.

Malignant hypercalcemia revealing a diffuse large B-cell lymphoma in a patient with a previous diagnosis of chronic myelomonocytic leukemia: An uncommon hematological coexistence

A 76-year-old patient previously admitted to the cardiology department for replacement of a right ventricular lead on a double-chamber pacemaker was admitted to the internal medicine department 15 days after for bronchopneumopathy. His past medical history was relevant for Type 2 diabetes mellitus, heart failure due to dilated hypokinetic heart disease, transcatheter aortic valve implantation (TAVI), and chronic myelomonocytic leukemia (CMML-0) diagnosed in 2021. Twenty-four hours after admission, the patient's general condition deteriorated abruptly, with the onset of drowsiness and psychomotor retardation. Laboratory exams revealed hypercalcemia at 4.18 mmol/L. Intensive hydration, calcitonin, and zoledronic acid were initiated and the patient was transferred to the nephrology intensive care unit where he underwent two sessions of hemodialysis to normalize serum calcium levels before readmission to internal medicine. Laboratory exams revealed low parathyroid hormone, normal 1-25-OH vitamin D, and increased parathyroid hormone-related peptide. Thoracoabdominal and positron emission tomography (PET) scan showed diffuse abdominopelvic peritoneal carcinosis associated with low-grade pleural effusion and multiple supra- and sub-diaphragmatic adenopathies, leading to a search for a solid tumor. The patient's clinical condition worsened leading to a transfer to the intensive care unit. The biopsy of a peritoneal carcinosis nodule confirmed the diagnosis of diffuse large B-cell lymphoma. Specific treatments were unsuccessful and the patient expired.

Review of clonal hematopoiesis, subtypes and its role in neoplasia and different morbidities

Clonal hematopoiesis (CH) is the development of a certain cell lineage which is the cornerstone of hematologic malignancy especially myeloid neoplasms, however, can also be found in old age (6th-7th decade). CH is caused by many different somatic mutations most commonly in DNMT3A, TET2, ASXL1, SF3B1 and TP53. It is detected by different sequencing methods, the most commonly used ones are next generation sequencing (NGS) which can be whole exome, whole genome sequencing or a panel for certain genes. CH is divided into multiple categories depending on the clinical picture associated with it into: clonal monocytosis of undetermined significance (CMUS), clonal hematopoiesis of indeterminate significance (CHIP), clonal cytopenia and monocytosis of undetermined significance (CCMUS) and clonal cytopenia of undetermined significance (CCUS). In order to diagose CH, first other hematologic malignancies must be ruled out CH is also associated with many different entities including lung cancer and some studies have shown that COVID-19 infections are affected by CH. Certain traits and infections are associated with CH including smoking, obesity, and cardiovascular disease. A minority of patients with CH progress to a malignant process (between 0.5 %-2 %) which do not require treatment, however, any patient with CH should be kept under surveillance in order to detect any malignancy early and be treated accordingly. SIMPLE SUMMARY: Clonal hematopoiesis (CH) is considered to be the predisposing factor for development of different hematologic neoplasms. With the help of NGS, patients with CH can be monitored more closely. Several studies have shown that these patients might develop hematologic neoplasms in their lifetime. It has been subdivided into multiple groups according to the clinical picture and/or blood counts.

Myelodysplastic Syndromes/Myeloproliferative Overlap Neoplasms and Differential Diagnosis in the WHO and ICC 2022 Era: A Focused Review

The myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) category comprises a varied group of myeloid neoplastic diseases characterized by clinical and pathologic overlapping features of both myelodysplastic and myeloproliferative neoplasms. For these reasons, these tumors are challenging in terms of diagnosis. The recent World Health Organization (WHO) 2022 classification and the International Consensus Classification (ICC) made changes in the classification of MDS/MPN compared to the previous 2016 WHO classification and improved the diagnostic criteria of these entities. The aim of this review is to describe the main entities reported in the more recent classifications, focusing on chronic myelomonocytic leukemia (CMML), MDS/MPN with neutrophilia (or atypical CML [aCML]), and MDS/MPN with SF3B1 mutation and thrombocytosis/MDS/MPN with ring sideroblasts and thrombocytosis. A particular emphasis is given to the differential diagnosis and analysis of subtle divergences and semantic differences between the WHO classification and the ICC for these entities.

[Molecular features of 109 patients with chronic myelomonocytic leukemia in a single center]

Objective: To explore the molecular features of chronic myelomonocytic leukemia (CMML) . Methods: According to 2022 World Health Organization (WHO 2022) classification, 113 CMML patients and 840 myelodysplastic syndrome (MDS) patients from March 2016 to October 2021 were reclassified, and the clinical and molecular features of CMML patients were analyzed. Results: Among 113 CMML patients, 23 (20.4%) were re-diagnosed as acute myeloid leukemia (AML), including 18 AML with NPM1 mutation, 3 AML with KMT2A rearrangement, and 2 AML with MECOM rearrangement. The remaining 90 patients met the WHO 2022 CMML criteria. In addition, 19 of 840 (2.3%) MDS patients met the WHO 2022 CMML criteria. At least one gene mutation was detected in 99% of CMML patients, and the median number of mutations was 4. The genes with mutation frequency ≥ 10% were: ASXL1 (48%), NRAS (34%), RUNX1 (33%), TET2 (28%), U2AF1 (23%), SRSF2 (21.1%), SETBP1 (20%), KRAS (17%), CBL (15.6%) and DNMT3A (11%). Paired analysis showed that SRSF2 was frequently co-mutated with ASXL1 (OR=4.129, 95% CI 1.481-11.510, Q=0.007) and TET2 (OR=5.276, 95% CI 1.979-14.065, Q=0.001). SRSF2 and TET2 frequently occurred in elderly (≥60 years) patients with myeloproliferative CMML (MP-CMML). U2AF1 mutations were often mutually exclusive with TET2 (OR=0.174, 95% CI 0.038-0.791, Q=0.024), and were common in younger (<60 years) patients with myelodysplastic CMML (MD-CMML). Compared with patients with absolute monocyte count (AMoC) ≥1×10(9)/L and <1×10(9)/L, the former had a higher median age of onset (60 years old vs 47 years old, P<0.001), white blood cell count (15.9×10(9)/L vs 4.4×10(9)/L, P<0.001), proportion of monocytes (21.5% vs 15%, P=0.001), and hemoglobin level (86 g/L vs 74 g/L, P=0.014). TET2 mutations (P=0.021) and SRSF2 mutations (P=0.011) were more common in patients with AMoC≥1×10(9)/L, whereas U2AF1 mutations (P<0.001) were more common in patients with AMoC<1×10(9)/L. There was no significant difference in the frequency of other gene mutations between the two groups. Conclusion: According to WHO 2022 classification, nearly 20% of CMML patients had AMoC<1×10(9)/L at the time of diagnosis, and MD-CMML and MP-CMML had different molecular features.

Progression in Myeloid Neoplasms: Beyond the Myeloblast

Disease progression in myelodysplastic syndromes (MDS), myelodysplastic-myeloproliferative neoplasms (MDS/MPN), and myeloproliferative neoplasms (MPN), altogether referred to as myeloid neoplasms (MN), is a major source of mortality. Apart from transformation to acute myeloid leukemia, the clinical progression of MN is mostly due to the overgrowth of pre-existing hematopoiesis by the MN without an additional transforming event. Still, MN may evolve along other recurrent yet less well-known scenarios: (1) acquisition of MPN features in MDS or (2) MDS features in MPN, (3) progressive myelofibrosis (MF), (4) acquisition of chronic myelomonocytic leukemia (CMML)-like characteristics in MPN or MDS, (5) development of myeloid sarcoma (MS), (6) lymphoblastic (LB) transformation, (7) histiocytic/dendritic outgrowths. These MN-transformation types exhibit a propensity for extramedullary sites (e.g., skin, lymph nodes, liver), highlighting the importance of lesional biopsies in diagnosis. Gain of distinct mutations/mutational patterns seems to be causative or at least accompanying several of the above-mentioned scenarios. MDS developing MPN features often acquire MPN driver mutations (usually JAK2), and MF. Conversely, MPN gaining MDS features develop, e.g., ASXL1, IDH1/2, SF3B1, and/or SRSF2 mutations. Mutations of RAS-genes are often detected in CMML-like MPN progression. MS ex MN is characterized by complex karyotypes, FLT3 and/or NPM1 mutations, and often monoblastic phenotype. MN with LB transformation is associated with secondary genetic events linked to lineage reprogramming leading to the deregulation of ETV6, IKZF1, PAX5, PU.1, and RUNX1. Finally, the acquisition of MAPK-pathway gene mutations may shape MN toward histiocytic differentiation. Awareness of all these less well-known MN-progression types is important to guide optimal individual patient management.

Myeloid NGS Analyses of Paired Samples from Bone Marrow and Peripheral Blood Yield Concordant Results: A Prospective Cohort Analysis of the AGMT Study Group

Background: Next generation sequencing (NGS) has become indispensable for diagnosis, risk stratification, prognostication, and monitoring of response in patients with myeloid neoplasias. Guidelines require bone marrow evaluations for the above, which are often not performed outside of clinical trials, indicating a need for surrogate samples. Methods: Myeloid NGS analyses (40 genes and 29 fusion drivers) of 240 consecutive, non-selected, prospectively collected, paired bone marrow/peripheral blood samples were compared. Findings: Very strong correlation (r = 0.91, p < 0.0001), high concordance (99.6%), sensitivity (98.8%), specificity (99.9%), positive predictive value (99.8%), and negative predictive value (99.6%) between NGS analyses of paired samples was observed. A total of 9/1321 (0.68%) detected mutations were discordant, 8 of which had a variant allele frequency (VAF) ≤ 3.7%. VAFs between peripheral blood and bone marrow samples were very strongly correlated in the total cohort (r = 0.93, p = 0.0001) and in subgroups without circulating blasts (r = 0.92, p < 0.0001) or with neutropenia (r = 0.88, p < 0.0001). There was a weak correlation between the VAF of a detected mutation and the blast count in either the peripheral blood (r = 0.19) or the bone marrow (r = 0.11). Interpretation: Peripheral blood samples can be used to molecularly classify and monitor myeloid neoplasms via NGS without loss of sensitivity/specificity, even in the absence of circulating blasts or in neutropenic patients.

What’s New in the Classification, Diagnosis and Therapy of Myeloid Leukemias

Myeloid leukemias are a broad group of hematological disorders, characterized by heterogeneous clinical and biological features. In recent years, unprecedented genetic discoveries and clinical–biological correlations have revolutionized the field of myeloid leukemias. The most relevant changes have specifically occurred in acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), chronic myeloid leukemia (CML) and myeloid neoplasms (MNs) with eosinophilia. The recently published International Consensus Classification (ICC) of myeloid neoplasms has addressed these changes, providing an updated framework and revised diagnostic criteria for such entities. This is also the aim of the 5th edition of the WHO classification of hematopoietic tumors, whose preliminary version was published in 2022. Parallel to this, new therapeutic options and novel molecular targets have changed the management of many myeloid entities, including AML and CML. This review aims to address the most relevant updates in the classification and diagnosis of AML, CMML, CML and MNs with eosinophilia. The state of the art of treatment and future therapeutic options for such disorders are also discussed.

DeepHeme: A generalizable, bone marrow classifier with hematopathologist-level performance

Morphology-based classification of cells in the bone marrow aspirate (BMA) is a key step in the diagnosis and management of hematologic malignancies. However, it is time-intensive and must be performed by expert hematopathologists and laboratory professionals. We curated a large, high-quality dataset of 41,595 hematopathologist consensus-annotated single-cell images extracted from BMA whole slide images (WSIs) containing 23 morphologic classes from the clinical archives of the University of California, San Francisco. We trained a convolutional neural network, DeepHeme, to classify images in this dataset, achieving a mean area under the curve (AUC) of 0.99. DeepHeme was then externally validated on WSIs from Memorial Sloan Kettering Cancer Center, with a similar AUC of 0.98, demonstrating robust generalization. When compared to individual hematopathologists from three different top academic medical centers, the algorithm outperformed all three. Finally, DeepHeme reliably identified cell states such as mitosis, paving the way for image-based quantification of mitotic index in a cell-specific manner, which may have important clinical applications.

New Insights into the Pathogenesis of Mastocytosis: Emerging Concepts in Diagnosis and Therapy

Mastocytosis is a heterogeneous group of neoplasms defined by a numerical increase and accumulation of clonal mast cells (MCs) in various organ systems. The disease may present as cutaneous mastocytosis or systemic mastocytosis (SM). On the basis of histopathological and molecular features, clinical variables, and organ involvement, SM is divided into indolent SM, smoldering SM, SM with an associated hematologic neoplasm, aggressive SM, and MC leukemia. Each variant is defined by unique diagnostic criteria and a unique spectrum of clinical presentations. A key driver of MC expansion and disease evolution is the oncogenic machinery triggered by mutant forms of KIT. The genetic background, additional somatic mutations, and comorbidities also contribute to the course and prognosis. Patients with SM may also suffer from mediator-related symptoms or even an MC activation syndrome. This article provides an update of concepts on the genetics, etiology, and pathology of mastocytosis, with emphasis on diagnostic criteria and new treatment concepts.

Clinical application of flow cytometry in patients with unexplained cytopenia and suspected myelodysplastic syndrome: A report of the European LeukemiaNet International MDS-Flow Cytometry Working Group

This article discusses the rationale for inclusion of flow cytometry (FCM) in the diagnostic investigation and evaluation of cytopenias of uncertain origin and suspected myelodysplastic syndromes (MDS) by the European LeukemiaNet international MDS Flow Working Group (ELN iMDS Flow WG). The WHO 2016 classification recognizes that FCM contributes to the diagnosis of MDS and may be useful for prognostication, prediction, and evaluation of response to therapy and follow-up of MDS patients.

A series of case studies illustrating the role of flow cytometry in the diagnostic work-up of myelodysplastic syndromes

Current guidelines recommend flow cytometric analysis as part of the diagnostic assessment of patients with cytopenia suspected for myelodysplastic syndrome. Herein we describe the complete work-up of six cases using multimodal integrated diagnostics. Flow cytometry assessments are illustrated by plots from conventional and more recent analysis tools. The cases demonstrate the added value of flow cytometry in case of hypocellular, poor quality, or ambiguous bone marrow cytomorphology. Moreover, they demonstrate how immunophenotyping results support clinical decision-making in inconclusive and clinically 'difficult' cases.

Monocytosis at the time of diagnosis has a negative prognostic impact in myelodysplastic syndromes with less than 5% bone marrow blasts

The prognostic impact of monocytosis has not yet been determined in patients with myelodysplastic syndromes (MDS). We examined absolute monocyte counts in the peripheral blood at the time of diagnosis in 1949 patients with a bone marrow blast count < 5%, a condition we call MDS < EB1 (MDS with a blast percentage lower than that of MDS with excess blasts 1, according to the WHO classification). Monocytosis (> 600/µl) was associated with higher median hemoglobin, WBC, and ANC, and more favorable karyotype (p = .001). Nevertheless, monocytosis was associated with shorter overall survival (OS) (108 vs. 126 months, p = .002) and earlier transformation into AML (p < .001). In patients with sideroblastic phenotype, the percentage of ring sideroblasts significantly correlated with the monocyte count (p = .005), and OS was significantly shorter when monocytosis was documented (88 vs. 132 months, p = .004). The survival disadvantage of patients with MDS < EB1 and peripheral blood monocytosis suggests that these patients suffer from a CMML-like disease. Even though they are generally classified as MDS with persistent monocytosis, such patients should be considered candidates for therapeutic options employed in CMML.

Molecular Mechanisms of Tyrosine Kinase Inhibitor Resistance in Chronic Myeloid Leukemia

The hematopoietic neoplasm chronic myeloid leukemia (CML) is a rare disease caused by chromosomal reciprocal translocation t(9;22)(q34:q11) with subsequent formation of the BCR-ABL1 fusion gene. This fusion gene encodes a constitutively active tyrosine kinase, which results in malignant transformation of the cells. Since 2001, CML can be effectively treated using tyrosine kinase inhibitors (TKIs) such as imatinib, which prevent phosphorylation of downstream targets by blockade of the BCR-ABL kinase. Due to its tremendous success, this treatment became the role model of targeted therapy in precision oncology. Here, we review the mechanisms of TKI resistance focusing on BCR-ABL1-dependent and -independent mechanisms. These include the genomics of the BCR-ABL1, TKI metabolism and transport and alternative signaling pathways.

Advances in myelodysplastic/myeloproliferative neoplasms

The myelodysplastic syndrome/myeloproliferative neoplasms (MDS/MPN) category includes a heterogeneous group of diseases characterized by the co-occurrence of clinical and pathologic features of both myelodysplastic and myeloproliferative neoplasms. The recently published International Consensus Classification of myeloid neoplasms revised the entities included in the MDS/MPN category as well as criteria for their diagnosis. In addition to the presence of one or more increased peripheral blood cell counts as evidence of myeloproliferative features, concomitant cytopenia as evidence of ineffective hematopoiesis is now an explicit requirement to diagnose the diseases included in this category. The increasing availability of modern gene sequencing has allowed better understanding of the biologic characteristics of these myeloid neoplasms. The presence of specific mutations in the appropriate clinicopathologic context is now included in the diagnostic criteria for some of MDS/MPN entities. In this review, we highlight what has changed in the diagnostic criteria of MDS/MPN from the WHO 2016 classification while providing practical guidance in diagnosing these diseases.

The International Consensus Classification of myelodysplastic syndromes and related entities

The International Consensus Classification (ICC) of myeloid neoplasms and acute leukemia has updated the classification of myelodysplastic syndromes (MDSs) and placed MDS in a broader group of clonal cytopenias that includes clonal cytopenia of undetermined significance (CCUS) and related entities. Although subject to some interobserver variability and lack of specificity, morphologic dysplasia remains the main feature that distinguishes MDS from other clonal cytopenias and defines MDS as a hematologic malignancy. The ICC has introduced some changes in the definition of MDS whereby some cases categorized as MDS based on cytogenetic abnormalities are now classified as CCUS, while SF3B1 and multi-hit TP53 mutations are now considered to be MDS-defining in a cytopenic patient. The ICC has also recognized several cytogenetic and molecular abnormalities that reclassify some cases of MDS with excess blasts as acute myeloid leukemia (AML) and has introduced a new MDS/AML entity that encompasses cases with 10-19% blasts that lie on the continuum between MDS and AML. Two new genetically defined categories of MDS have been introduced: MDS with mutated SF3B1 and MDS with mutated TP53, the latter requiring bi-allelic aberrations in the TP53 gene. The entity MDS, unclassifiable has been eliminated. These changes have resulted in an overall simplification of the MDS classification scheme from 8 separate entities (including 1 that was genetically defined) in the revised 4th edition WHO classification to 7 separate entities (including 3 that are genetically defined) in the ICC.

Treatment Outcomes and Prognostic Factors in 66 Patients with Chronic Myelomonocytic Leukemia (CMML) in a Single Center

INTRODUCTION

Chronic myelomonocytic leukemia (CMML) is a rare hematological malignancy bearing of both myelodysplastic syndrome and myeloproliferative neoplasm characteristics. Despite the low incidence, the clinical diagnosis of CMML was difficult and the survival was poor. The optimal first-line therapy for CMML still remains a matter of debate.

METHODS

We retrospectively analyzed the clinical characteristics of 66 CMML patients in a single center during the past 10 years and studied the survival status of CMML patients in the real world and the influence of treatment methods on the prognosis of patients.

RESULTS

For the 66 CMML patients, the median age was 60 years old (IQR 47.0-67.0), and an approximately 1.6:1.0 male-to-female ratio was found. CMML-0, CMML-1 and CMML-2 accounted for 13.7% (9/66), 43.9% (29/66) and 42.4% (28/66), respectively. The chromosome abnormality rate was 27.2% (18/66). Gene mutation was detected in 60 patients by sequenced in first-generation with 51.1% (22/43) gene mutations and in NGS with 82.3% (14/17) gene mutations. The top three mutation genes were ASXL1MT (11/60, 18.3%), TET2MT (10/60, 16.7%), and SRSF2 MT (9/60, 15.0%). There were 27 patients in supportive therapy group, and 39 patients in chemotherapy group including patients undergoing HSCT. Patients in chemotherapy group showed better OS than those in the supportive group before and after PSM analysis with p < 0.05. Patients with blast cell in bone marrow ≥10% or WHO CMML-2 benefited more from chemotherapy treatment achieving better OS. Multivariate analysis showed that supportive therapy and intermediate-2/high in CPSS were independent risk factors for OS after PSM.

DISCUSSION

Chemotherapy including hypomethylating agents prolonged overall survival of CMML patients, especially in patients with blast cell ≥10% in bone marrow or WHO CMML-2 comparing with supportive therapy. Sequencing may provide direct insight into the molecular mechanism by detection of gene mutation, enabling personalized treatment in the future.

The ABNL-MARRO 001 study: a phase 1-2 study of randomly allocated active myeloid target compound combinations in MDS/MPN overlap syndromes

BACKGROUND

Myelodysplastic/myeloproliferative neoplasms (MDS/MPN) comprise several rare hematologic malignancies with shared concomitant dysplastic and proliferative clinicopathologic features of bone marrow failure and propensity of acute leukemic transformation, and have significant impact on patient quality of life. The only approved disease-modifying therapies for any of the MDS/MPN are DNA methyltransferase inhibitors (DNMTi) for patients with dysplastic CMML, and still, outcomes are generally poor, making this an important area of unmet clinical need. Due to both the rarity and the heterogeneous nature of MDS/MPN, they have been challenging to study in dedicated prospective studies. Thus, refining first-line treatment strategies has been difficult, and optimal salvage treatments following DNMTi failure have also not been rigorously studied. ABNL-MARRO (A Basket study of Novel therapy for untreated MDS/MPN and Relapsed/Refractory Overlap Syndromes) is an international cooperation that leverages the expertise of the MDS/MPN International Working Group (IWG) and provides the framework for collaborative studies to advance treatment of MDS/MPN and to explore clinical and pathologic markers of disease severity, prognosis, and treatment response.

METHODS

ABNL MARRO 001 (AM-001) is an open label, randomly allocated phase 1/2 study that will test novel treatment combinations in MDS/MPNs, beginning with the novel targeted agent itacitinib, a selective JAK1 inhibitor, combined with ASTX727, a fixed dose oral combination of the DNMTi decitabine and the cytidine deaminase inhibitor cedazuridine to improve decitabine bioavailability.

DISCUSSION

Beyond the primary objectives of the study to evaluate the safety and efficacy of novel treatment combinations in MDS/MPN, the study will (i) Establish the ABNL MARRO infrastructure for future prospective studies, (ii) Forge innovative scientific research that will improve our understanding of pathogenetic mechanisms of disease, and (iii) Inform the clinical application of diagnostic criteria, risk stratification and prognostication tools, as well as response assessments in this heterogeneous patient population.

TRIAL REGISTRATION

This trial was registered with ClinicalTrials.gov on August 19, 2019 (Registration No. NCT04061421).

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.

Outcomes and molecular profile of oligomonocytic CMML support its consideration as the first stage in the CMML continuum

Oligomonocytic chronic myelomonocytic leukemia (OM-CMML) patients are currently classified into the different categories of the 2017 WHO MDS classification. However recent data support considering OM-CMML as a specific subtype of chronic myelomonocytic leukemia (CMML) given their similar clinical, genomic and immunophenotypic profiles. The main purpose of our study was to provide survival outcome data of a well-annotated series of 42 patients with OM-CMML and to compare them to 162 patients with CMML, 120 with dysplastic type (D-CMML) and 42 with proliferative type (P-CMML). OM-CMML showed significantly longer overall survival (OS) and acute myeloid leukemia-free survival than CMML patients considered as a whole group, and when compared to D-CMML and P-CMML, respectively. Moreover, gene mutations associated with increased proliferation (i.e.: ASXL1 and RAS-pathway mutations) were identified as independent adverse prognostic factors for OS in our series. We found that at a median follow-up of 53.47 months, 29.3% of our OM-CMML patients progressed to D-CMML, and at a median follow-up of 46.03 months, 28.6% of our D-CMML progressed to P-CMML. These data support the existence of an evolutionary continuum among OM-CMML, D-CMML and P-CMML. In this context, we observed that harboring more than 3 mutated genes, ASXL1 mutations and a peripheral blood monocyte percentage above 20% significantly predicted shorter time of progression of OM-CMML into overt CMML. These variables were also detected as independent adverse prognostic factors for OS in OM-CMML. These data support the consideration of OM-CMML as the first evolutionary stage within the proliferative continuum of CMML.

A Case of Chronic Myelomonocytic Leukemia Unmasked After Receiving J&J COVID-19 Vaccine

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disease that comes under the overlap syndrome (myelodysplastic and myeloproliferative disorders). CMML is characterized by peripheral blood monocytosis and bone marrow dysplasia. The pathogenesis of CMML is poorly understood. Although cytogenetic and molecular abnormalities are common, they are not diagnostic. Herein, we present a rare case of CMML after receiving the J&J COVID-19 vaccine with the rare association of limited scleroderma. Based on the Surveillance, Epidemiology, and End Result (SEER) cancer statistics review 2014-2018, the five-year age-adjusted incidence rate of CMML in both sexes is 0.5/100,000, with greater incidence in males (0.7/100,000) compared to females (0.3/100,000). We emphasize the fact that, based on the previous studies reported, the association of scleroderma with CMML is very rare. Our patient had concomitant CMML and scleroderma, which were unmasked after the patient received the COVID-19 vaccine. Our case suggests the possibility of developing CMML after receiving the J&J COVID vaccine. Immunization has always been a life-saving intervention in history. As the world is foreseeing getting the COVID-19 vaccine, it is essential to report all the possible adverse events for safety monitoring. Physicians should be aware of this unusual complication of the vaccine, and more cases are needed to confirm the association between them.

Prognostic value of a new clinically-based classification system in patients with CMML undergoing allogeneic HCT: a retrospective analysis of the EBMT-CMWP

Recently a new three-group clinical classification was reported by an International Consortium to stratify CMML patients with regard to prognosis. The groups were defined as follows: (1) Myelodysplastic (MD)-CMML: WBC ≤ 10 × 109/l, circulating immature myeloid cells (IMC) = 0, no splenomegaly; (2) MD/MP (overlap)-CMML: WBC 10-20 × 109/l or WBC ≤ 10 × 109/l but IMC > 0 and/or splenomegaly; (3) Myeloproliferative (MP)-CMML: WBC > 20 × 109/l. By analysing EBMT Registry patients who underwent allo-HCT for CMML between 1997 and 2016, we aimed to determine the impact of this classification on transplantation outcome and to make a comparison with the conventional WHO classification (CMML-0/CMML-1/CMML-2). Patient grouping was based on the data registered at time of transplantation, with IMC replaced by peripheral blasts. Among 151 patients included in the analysis, 38% were classified as MD-CMML, 42% as MD/MP-CMML and 20% as MP-CMML. With a median survival of 17 months in the whole series, MD-CMML patients were distinguished as a low-risk group with higher CR rate at transplant and a longer post-transplant 2-year progression-free survival in comparison to others (44.5% vs 33.5%, respectively), whereas the WHO classification was superior in identifying high-risk patients (CMML-2) with inferior survival outcomes.

Monocytosis and its association with clonal hematopoiesis in community-dwelling individuals

Monocytosis associates with a higher frequency of CH with spliceosome and multiple gene mutations, but not isolated DNMT3A/TET2/ASXL1.

Few community-based individuals with monocytosis and CH develop myeloid malignancy (among 166 individuals: n = 4 cases including n = 1 CMML).

Monocytosis may occur in numerous inflammatory conditions but is also the defining feature of chronic myelomonocytic leukemia (CMML). Clonal somatic mutations detectable in CMML may occur with aging in otherwise healthy individuals, so-called “clonal hematopoiesis” (CH). We investigated whether the combination of CH and monocytosis would represent an early developmental stage of CMML. We studied community-dwelling individuals with monocytosis (≥1 × 10⁹/L and ≥10% of leukocytes) in the population-based Lifelines cohort (n = 144 676 adults). The prevalence and spectrum of CH were evaluated for individuals ≥60 years with monocytosis (n = 167 [0.8%]), and control subjects 1:3 matched for age and sex (n = 501). Diagnoses of hematological malignancies were retrieved by linkage to the Netherlands Cancer Registry (NCR). Monocyte counts and the prevalence of monocytosis increased with advancing age. Older individuals with monocytosis more frequently carried CH (50.9% vs 35.5%; P < .001). Monocytosis is associated with enrichment of multiple gene mutations (P = .006) and spliceosome mutations (P = .007) but not isolated mutated DNMT3A, TET2, or ASXL1. Persistent monocytosis over 4 years was observed in 30/102 evaluable individuals and associated with a higher prevalence of CH (63%). Myeloid malignancies, including 1 case of CMML, developed in 4 individuals with monocytosis who all carried CH. In conclusion, monocytosis and CH both occur at an older age and do not necessarily reflect clonal monocytic proliferation. In a fraction of older subjects with monocytosis, CH might constitute early clonal dominance in developing malignant myelomonocytic disease. Mutational spectra deviating from age-related CH require attention.

The mutational landscape in chronic myelomonocytic leukemia and its impact on allogeneic hematopoietic cell transplantation outcomes: a Center for Blood and Marrow Transplantation Research (CIBMTR) analysis

Somatic mutations are recognized as an important prognostic factor in chronic myelomonocytic leukemia (CMML). However, limited data are available regarding their impact on outcomes after allogeneic hematopoietic cell transplantation (HCT). In this registry analysis conducted in collaboration with the Center for International Blood and Marrow Transplantation Registry database/sample repository, we identified 313 adult patients with CMML (median age: 64 years, range, 28- 77) who underwent allogeneic HCT during 2001-2017 and had an available biospecimen in the form of a peripheral blood sample obtained prior to the start of conditioning. In multivariate analysis, a CMML-specific prognostic scoring system (CPSS) score of intermediate-2 (HR=1.46, P=0.049) or high (HR=3.22, P=0.0004) correlated significantly with overall survival. When the molecularly informed CPSS-Mol prognostic model was applied, a high CPSS-Mol score (HR=2 P=0.0079) correlated significantly with overall survival. The most common somatic mutations were in ASXL1 (62%), TET2 (35%), KRAS/NRAS (33% combined), and SRSF2 (31%). DNMT3A and TP53 mutations were associated with decreased overall survival (HR=1.70 [95% CI: 1.11-2.60], P=0.0147 and HR=2.72 [95% CI: 1.37-5.39], P=0.0042, respectively) while DNMT3A, JAK2, and TP53 mutations were associated with decreased disease-free survival (HR=1.66 [95% CI: 1.11-2.49], P=0.0138, HR=1.79 [95% CI: 1.06-3.03], P=0.0293, and HR=2.94 [95% CI: 1.50-5.79], P=0.0018, respectively). The only mutation associated with increased relapse was TP53 (HR=2.94, P=0.0201). Nonetheless, the impact of TP53 mutations specifically should be interpreted cautiously given their rarity in CMML. We calculated the goodness of fit measured by Harrell's C-index for both the CPSS and CPSS-Mol, which were very similar. In summary, via registry data we have determined the mutational landscape in patients with CMML who underwent allogeneic HCT, and demonstrated an association between CPSS-Mol and transplant outcomes although without major improvement in the risk prediction beyond that provided by the CPSS.

Myelodysplastic/myeloproliferative neoplasms-unclassifiable with isolated isochromosome 17q represents a distinct clinico-biologic subset: a multi-institutional collaborative study from the Bone Marrow Pathology Group

Classification of myeloid neoplasms with isolated isochromosome i(17q) [17p deletion with inherent monoallelic TP53 loss plus 17q duplication] is controversial. Most cases fall within the WHO unclassifiable myelodysplastic/myeloproliferative neoplasms (MDS/MPN-U) category. The uniformly dismal outcomes warrant better understanding of this entity. We undertook a multi-institutional retrospective study of 92 adult MDS/MPN-U cases from eight institutions. Twenty-nine (32%) patients had isolated i(17q) [MDS/MPN-i(17q)]. Compared to MDS/MPN without i(17q), MDS/MPN-i(17q) patients were significantly younger, had lower platelet and absolute neutrophil counts, and higher frequency of splenomegaly and circulating blasts. MDS/MPN-i(17q) cases showed frequent bilobed neutrophils (75% vs. 23%; P = 0.03), hypolobated megakaryocytes (62% vs. 20%; P = 0.06), and a higher frequency of SETBP1 (69% vs. 5%; P = 0.002) and SRSF2 (63% vs. 5%; P = 0.006) mutations that were frequently co-existent (44% vs. 0%; P = 0.01). TP53 mutations were rare. The mutation profile of MDS/MPN-U-i(17q) was similar to other myeloid neoplasms with i(17q) including atypical chronic myeloid leukemia, chronic myelomonocytic leukemia, myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis, myelodysplastic syndrome and acute myeloid leukemia, with frequent concomitant SETBP1/SRSF2 mutations observed across all the diagnostic entities. Over a median follow-up of 52 months, patients with MDS/MPN-i(17q) showed a shorter median overall survival (11 vs. 28 months; P < 0.001). The presence of i(17q) retained independent poor prognostic value in multivariable Cox-regression analysis [HR 3.686 (1.17-11.6); P = 0.026] along with splenomegaly. We suggest that MDS/MPN-i(17q) warrants recognition as a distinct subtype within the MDS/MPN-U category based on its unique clinico-biologic features and uniformly poor prognosis.

Chronic myelomonocytic leukemia: 2022 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder with overlapping features of myelodysplastic syndromes and myeloproliferative neoplasms, with an inherent risk for leukemic transformation (~15% over 3-5 years).

DIAGNOSIS

Diagnosis is based on the presence of sustained (>3 months) peripheral blood monocytosis (≥1 × 10⁹ /L; monocytes ≥10%), usually with accompanying bone marrow dysplasia. Clonal cytogenetic abnormalities occur in ~30% of patients, while >90% have somatic gene mutations. Mutations involving TET2 (~60%), SRSF2 (~50%), ASXL1 (~40%), and the oncogenic RAS pathway (~30%) are frequent, while the presence of ASXL1 and DNMT3A mutations and the absence of TET2 mutations negatively impact overall survival.

RISK-STRATIFICATION

Molecularly integrated prognostic models include the Groupe Français des Myélodysplasies, Mayo Molecular Model (MMM), and the CMML specific prognostic model. Risk factors incorporated into the MMM include presence of truncating ASXL1 mutations, absolute monocyte count >10 × 10⁹ /L, hemoglobin <10 g/dL, platelet count <100 × 10⁹ /L, and the presence of circulating immature myeloid cells. The MMM stratifies CMML patients into four groups: high (≥3 risk factors), intermediate-2 (2 risk factors), intermediate-1 (1 risk factor), and low (no risk factors), with median survivals of 16, 31, 59, and 97 months, respectively.

RISK-ADAPTED THERAPY

Hypomethylating agents such as 5-azacitidine and decitabine are commonly used, with overall response rates of ~40%-50% and complete remission rates of ~7%-17%; with no impact on mutational allele burdens. Allogeneic stem cell transplant is the only potentially curative option but is associated with significant morbidity and mortality.

Coexistence of Chronic Myelomonocytic Leukemia and Ulcerative Colitis With Rapid Progression to Acute Myelomonocytic Leukemia: A Case Report

Chronic myelomonocytic leukemia (CMML) is a clonal myeloid neoplasm characterized by sustained peripheral blood monocytosis and variable dyspoiesis. We present a case of a 64-year-old male who presented with severe non-bloody diarrhea, peripheral blood neutrophilia, and monocytosis. He was diagnosed with myeloproliferative CMML type 0 and ulcerative colitis (UC). Next-generation DNA sequencing of a bone marrow sample demonstrated mutations of the TET2, ASXL1, NRAS, and SRSF2 genes along with low-level JAK2^V617F mutation. Both TET2 and SRSF2 mutations are associated with systemic inflammatory and autoimmune disease (SIAD), which includes UC. The patient's UC was managed successfully with vedolizumab infusions. The patient's concurrent CMML was monitored with a "wait and watch" approach. After five months, the patient asymptomatically tested positive for coronavirus disease 2019 (COVID-19). Seven months after his diagnosis of CMML, the patient presented in severe respiratory distress with acute left upper quadrant pain, splenomegaly, and multiorgan failure. A peripheral blood smear demonstrated marked leukocytosis (283 x 10^9 /L) with 39% blasts/promonocytes without Auer rods. The patient was diagnosed with acute myeloid leukemia with myelomonocytic features (AMML). In this report, we discuss the diagnosis of combined CMML and SIAD, mechanisms of immunoregulatory dysfunction that have been suggested to result in CMML progression, and the clinicopathologic significance of the patient's molecular abnormalities.