Analysis of CSF3R mutations in atypical chronic myeloid leukemia and other myeloid malignancies.

We report a series of patients with CSF3R-mutant (CSF3Rmut) atypical chronic myeloid leukemia (aCML), chronic neutrophilic leukemia (CNL) or other hematologic malignancies. We included 25 patients: 5 aCML and 4 CNL CSF3Rmut patients; 1 aCML, 2 CNL, and 2 myelodysplastic/myeloproliferative neoplasm, not otherwise specified patients without CSF3R mutation; and 11 CSF3Rmut patients with other diseases [8 acute myeloid leukemia (AML), 1 chronic myelomonocytic leukemia (CMML), 1 myelodysplastic syndrome (MDS), and 1 acute lymphoblastic leukemia (ALL)]. Patients with aCML or CNL were tested by Sanger sequencing and pyrosequencing to identify CSF3R T618I. Twenty-two patients underwent gene panel analysis. CSF3R mutations, mostly T618I (8/9), were found at high frequencies in both aCML and CNL patients [5/6 aCML and 4/6 CNL]. Two aCML patients in early adulthood with CSF3R T618I and biallelic or homozygous CEBPA mutations without other mutations presented with increased blasts and exhibited remission for >6 years after transplantation. The other 7 CSF3Rmut aCML or CNL patients were elderly adults who all had ASXL1 mutations and frequently presented with SEBP1 and SRSF2 mutations. Five AML patients had CSF3R exon 14 or 15 point mutations, and 6 other patients (3 AML, 1 CMML, 1 MDS, and 1 ALL) had truncating mutations, demonstrating differences in leukocyte counts and mutation status. In conclusion, CSF3R mutations were found at a higher frequency in aCML patients than in previous studies, which might reflect ethnic differences. Additional studies are needed to confirm these findings and the relationship between CSF3R and CEBPA mutations.

Atypical CML: diagnosis and treatment.

Atypical chronic myeloid leukemia (aCML) is included in the group of myelodysplastic/myeloproliferative neoplasms by the International Consensus Classification and has been renamed as MDS/MPN with neutrophilia by the fifth edition of World Health Organization classification. It is always characterized by morphologic identification of granulocytic dysplasia with >10% circulating immature myeloid cells, 2 distinguished features that differentiate this disease among the others. Somatic mutations may help to diagnose but are not specifically pathognomonic of the disease, with the most detected including ASXL1, SETBP1, NRAS, KRAS, SRSF2, and TET2 and with low-frequency CBL, CSF3R, JAK2, and ETNK1. The genomic landscape of aCML has been recently unravelling, revealing that SETBP1 and ETNK1 are usually not ancestral but secondary events associated with disease progression. Unfortunately, until now, no consensus on risk stratification and treatment has been developed: Mayo Clinic prognostic score identified as adverse events age >67 years, hemoglobin level <10  g/dL, and TET2 mutations. Although some possible genetic markers have been identified, allogeneic transplant remains the only curative strategy.

Characteristics, primary treatment, and survival of MDS/MPN with neutrophilia: a population-based study.

Myelodysplastic and myeloproliferative neoplasms (MDS/MPN) with neutrophilia, until recently called atypical chronic myeloid leukemia (aCML), being part of the MDS/MPN is a very rare disease with poor prognosis. Although emerging data reveal its cytogenetic and molecular profile, integrated survival and treatment data remain scarce. We analyzed a cohort of 347 adult patients diagnosed with MDS/MPN with neutrophilia, registered in the Netherlands Cancer Registry between 2001 and 2019. Our demographic baseline data align with other cohorts. We observed cytogenetic aberrations exclusively in patients aged >65 years, with trisomy 8 being the most common abnormality. We identified 16 distinct molecular mutations, with some patients (16/101) harboring up to 3 different mutations; ASXL1 being the most frequent one (22%). In a multivariable Cox regression analysis, only age, hemoglobin level and allogeneic hematopoietic stem cell transplant (alloHSCT) were associated with overall survival (aged >65 years; hazard ratio [HR] 1.85; P = .001 and alloHSCT HR, 0.51; P = .039). Because no other treatment modality seemed to affect survival and might cause toxicity, we propose that all patients eligible for alloHSCT should, whenever possible, receive an allogeneic transplant. It is imperative that we strive to improve outcomes for patients who are not eligible for alloHSCT. Tackling this challenge requires international collaborative efforts to conduct prospective intervention studies.

CSF3R-mutant chronic myelomonocytic leukemia is a distinct clinically subset with abysmal prognosis: a case report and systematic review of the literature.

Chronic myelomonocytic leukemia (CMML) is a myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) chacaterized by persistent peripheral blood monocytosis, hypercellular bone marrow and dysplasia at least in one myeloid lineage. CMML shares much of its molecular landscape with other myeloid neoplasms, while differs from others such as chronic neutrophilic leukemia (CNL), given the high frequency of CSF3R mutations in the latter. In this article, we report a case of CSF3R-mutated CMML and dissect this rare entity by reviewing the medical literature, with the intent to understand how this rare mutation shapes CMML's clinical and morphological phenotype. CSF3R-mutated CMML emerges as a rare entity meeting the ICC/WHO diagnostic criteria for CMML and simultaneously showing clinical-pathological and molecular traits of CNL and atypical chronic myeloid leukemia, rising an important and difficult diagnostic and therapeutical issue.

CCND2 mutations in atypical chronic myeloid leukemia: a report of two cases.

Atypical chronic myeloid leukemia (aCML) is a rare MDS/MPN disease characterized by the absence of BCR::ABL1 rearrangement and well known typical mutations associated with myeloproliferative disorders. Mutational landscape associated with this disease was recently described with frequent involvement of SETBP1 and ETNK1 mutations. CCND2 mutations have not been frequently detected in MPN or MDS/MPN patients. We describe two cases of aCML with two CCND2 mutations in 280 and 281 codons which rapidly develop progressive characteristics, and we reviewed the literature about this unfavorable association, suggesting a role as a new possible marker of aggressive disease.

Molecular genetics and management of world health organization defined atypical chronic myeloid leukemia.

Atypical chronic myeloid leukemia (CML) is a rare BCR::ABL1-negative hematopoietic stem cell disease characterized by granulocytic proliferation and granulocytic dysplasia. Due to both the challenging diagnosis and the rarity of atypical CML, comprehensive molecular annotation-based analyses of this disease population have been scarce, and it is currently difficult to identify the optimal treatment for atypical CML. To explore atypical CML genomic landscape and treatment options, we performed a systematic retrospective of the clinical data and outcomes of 31 atypical CML patients. We observed that the molecular landscape of atypical CML was highly heterogeneous, with multiple molecular events driving its pathogenesis. Patients with atypical CML had a low response to current therapies, with an overall response rate (ORR) of 33.3% to hypomethylating agent (HMA)-based therapy. The current treatment strategies, including hematopoietic stem cell transplantation (HSCT), did not improve overall survival (OS) in atypical CML patients, with a median survival of 20 months. Thus, the benefits from HSCT and candidates for HSCT remain to be further evaluated. Acute myeloid leukemia (AML)-like chemotherapy followed by bridging allogeneic HSCT may be an ideal regimen for suitable individuals. The large-scale and prospective clinical studies will help to address the dilemma.

Myelodysplastic/myeloproliferative neoplasm with neutrophilia (atypical chronic myeloid leukemia-aCML).

A case of myelodysplastic/myeloproliferative neoplasm with neutrophilia (aCML) with SETBP1 and ASXL1 mutations.

Atypical chronic myeloid leukemia and myelodysplastic/myeloproliferative neoplasm, not otherwise specified: 2023 update on diagnosis, risk stratification, and management.

DISEASE OVERVIEW: Atypical chronic myeloid leukemia (aCML) and myelodysplastic/myeloproliferative (MDS/MPN) neoplasms, not otherwise specified (NOS), are MDS/MPN overlap neoplasms characterized by leukocytosis, in the absence of monocytosis and eosinophilia, with <20% blasts in the blood and bone marrow. DIAGNOSIS: aCML, previously known as aCML, BCR::ABL1 negative, was renamed as aCML by the ICC classification, and as MDS/MPN with neutrophilia by the 5th edition of the WHO classification. This entity is characterized by dysplastic neutrophilia with immature myeloid cells comprising ≥10% of the white blood cell count, with prominent dysgranulopoiesis. MDS/MPN-NOS consists of MDS/MPN overlap neoplasms not meeting criteria for defined categories such as chronic myelomonocytic leukemia (CMML), MDS/MPN-ring sideroblasts-thrombocytosis (MDS/MPN-RS-T), and aCML. MUTATIONS AND KARYOTYPE: Cytogenetic abnormalities are seen in 40-50% of patients in both categories. In aCML, somatic mutations commonly encountered include ASXL1, SETBP1, ETNK1, and EZH2 whereas MDS/MPN-NOS can be further stratified by mutational profiles into CMML-like, MDS/MPN-RS-T-like, aCML-like, TP35-mutated, and "others", respectively. RISK STRATIFICATION: The Mayo Clinic aCML model stratifies patients based on age >67 years, hemoglobin <10 g/dl, and the presence of TET2 mutations into low-risk (0-1 points) and high-risk (>2 points) groups, with median survivals of 18 and 7 months, respectively. MDS/MPN-NOS patients have traditionally been risk stratified using MDS risk models such as IPSS and IPSS-R. TREATMENT: Leukocytosis and anemia are managed like lower risk MPN and MDS. DNMT inhibitors have been used in both entities with suboptimal response rates. Allogeneic stem cell transplant remains the only curative strategy but is associated with high morbidity and mortality.

ETNK1 mutation occurs in a wide spectrum of myeloid neoplasms and is not specific for atypical chronic myeloid leukemia.

BACKGROUND: ETNK1 mutation has been suggested as a useful tool to support the diagnosis of atypical chronic myeloid leukemia. ETNK1 mutations, however, occur in other myeloid neoplasms. METHODS: The authors assessed the clinicopathologic and molecular genetic features of 80 ETNK1-mutated myeloid neoplasms. RESULTS: Thirty-seven neoplasms (46%) were classified as myelodysplastic syndrome, 17 (21%) were classified as myelodysplastic/myeloproliferative neoplasm, 14 (18%) were classified as acute myeloid leukemia, and 12 (15%) were classified as myeloproliferative neoplasm. ETNK1 mutations were detected at the first test in 96% of patients, suggesting that ETNK1 mutation is an early event in pathogenesis. ETNK1 mutations represented the dominant clone in 63% of patients and was persistently dominant in 93%. The variant allele frequencies were usually higher in acute myeloid leukemia and increased upon leukemic transformation. ETNK1 mutation was accompanied by coexisting mutations in all patients, with ASXL1 (50%), TET2 (25%), EZH2 (24%), RUNX1 (24%), and SRSF2 (24%) mutations being the most common. Neoplasms with ETNK1 mutations were associated with morphologic dysplasia, increased blasts, myelofibrosis, and noncomplex karyotypes. With a median follow-up of 16.5 months, 30 patients died, 44 had persistent disease, and four achieved complete remission after stem cell transplantation. CONCLUSIONS: ETNK1 mutation is present in various myeloid neoplasms, often as an early event and a dominant clone and always with concurrent mutations. It may play an important role in the pathogenesis and progression of myeloid neoplasms by causing DNA damage and inducing other mutations and genomic instability, and it may serve as a potential therapeutic target. ETNK1 mutation is not disease-specific and should be interpreted with caution to classify myeloid neoplasms.

CNL and aCML should be considered as a single entity based on molecular profiles and outcomes.

Chronic neutrophilic leukemia (CNL) and atypical chronic myeloid leukemia (aCML) are rare myeloid disorders that are challenging with regard to diagnosis and clinical management. To study the similarities and differences between these disorders, we undertook a multicenter international study of one of the largest case series (CNL, n = 24; aCML, n = 37 cases, respectively), focusing on the clinical and mutational profiles (n = 53 with molecular data) of these diseases. We found no differences in clinical presentations or outcomes of both entities. As previously described, both CNL and aCML share a complex mutational profile with mutations in genes involved in epigenetic regulation, splicing, and signaling pathways. Apart from CSF3R, only EZH2 and TET2 were differentially mutated between them. The molecular profiles support the notion of CNL and aCML being a continuum of the same disease that may fit best within the myelodysplastic/myeloproliferative neoplasms. We identified 4 high-risk mutated genes, specifically CEBPA (ß = 2.26, hazard ratio [HR] = 9.54, P = .003), EZH2 (ß = 1.12, HR = 3.062, P = .009), NRAS (ß = 1.29, HR = 3.63, P = .048), and U2AF1 (ß = 1.75, HR = 5.74, P = .013) using multivariate analysis. Our findings underscore the relevance of molecular-risk classification in CNL/aCML as well as the importance of CSF3R mutations in these diseases.

[BCR-ABL1 negative chronic myeloid leukemia: report of two cases]. / Leucemia mieloide crónica atípica BCR-ABL1 negativa: reporte de 2 casos.

BCR-ABL1 negative atypical chronic myeloid leukemia (aCML) is a rare type of myeloproliferative / myelodysplastic syndrome characterized by leukocytosis and proliferation of dysplastic neutrophilic precursors in the absence of positivity for the BCR-ABL1 fusion gene. We report a 66-year-old woman and a 57-year-old man with aCML, who initially presented with general malaise and weight loss, associated with anemia, thrombocytopenia, and leukocytosis with left shift and dysplasia in the neutrophil series. Both evolved unfavorably after admission and died a few days later due to multiple organ failure.

Leucemia mieloide crónica atípica BCR-ABL1 negativa: reporte de 2 casos / BCR-ABL1 negative chronic myeloid leukemia: report of two cases

BCR-ABL1 negative atypical chronic myeloid leukemia (aCML) is a rare type of myeloproliferative / myelodysplastic syndrome characterized by leukocytosis and proliferation of dysplastic neutrophilic precursors in the absence of positivity for the BCR-ABL1 fusion gene. We report a 66-year-old woman and a 57-year-old man with aCML, who initially presented with general malaise and weight loss, associated with anemia, thrombocytopenia, and leukocytosis with left shift and dysplasia in the neutrophil series. Both evolved unfavorably after admission and died a few days later due to multiple organ failure.

Hydroxyurea- a cost effective treatment in developing countries for Atypical Chronic Myeloid Leukemia (aCML): Case Report of Two Patients.

INTRODUCTION: Atypical chronic myeloid leukaemia (aCML) is a rare chronic myeloproliferative disorder with a poor prognosis. CASE REPORT: This case report presents two cases of male geriatric patients, both referred from primary care in rural areas and received at an urban clinic in a tertiary care hospital on separate instances. The first patient complained of low-grade fever (on/off), generalized body aches, rapid weight loss and shortness of breath for the last 2 months. The second patient arrived pale looking with symptoms of generalized body aches, dizziness and anorexia. Both patients were diagnosed to have aCML according to the World Health organization criteria. MANAGEMENT & OUTCOME: Both the patients were from a low economic bracket and were treated with Hydroxyurea a relatively economic medicine successfully. The follow-up lasted for 12 months in both cases. No progression to acute myeloid leukaemia (AML) or relapse was observed. DISCUSSION: This case report shows the promising results of Hydroxyurea in treating aCML and can be a cost effective alternate to other expensive treatments (allogeneic hematopoietic stem cell transplantation) and expensive medicines in lower and middle-income countries especially for resource-limited patients. These two cases show promising evidence for further studies to evaluate and conduct pharmaco-economic evaluations as well as clinical trials to compare hydroxyurea with other available alternative treatments for an affordable therapeutic option towards prevention of relapse and disease free survival after aCML.

Response to blinatumomab or inotuzumab ozogamicin for isolated extramedullary relapse of adult acute lymphoblastic leukemia after allogeneic hematopoietic cell transplantation: a case study.

Isolated extramedullary relapse (EMR) without bone marrow relapse (BMR) after allogeneic hematopoietic cell transplantation (allo-HCT) is a rare condition in patients with acute lymphoblastic leukemia (ALL), and the role of immunotherapeutic agents for these patients remains unclear. We analyzed treatment outcomes of blinatumomab or inotuzumab ozogamicin (INO) as first- or second-line salvage therapy in nine patients with Philadelphia chromosome-negative B-cell precursor ALL presenting with isolated EMR after previous allo-HCT. In seven patients receiving blinatumomab as first-line salvage therapy, 4 (57.1%) achieved complete remission (CR). Among the three patients without remission after blinatumomab, two switched to INO and subsequently showed responses {one CR and one partial response [PR]}, and one switched to multiagent chemotherapy that led to CR. In the two patients receiving first-line salvage therapy with INO, one showed PR and the other achieved CR. Overall, 6 (66.7%) of nine patients achieved CR, and five of them proceeded to allo-HCT in CR. The median overall survival after relapse was 27.8 months. In conclusion, both blinatumomab and INO showed good response rates and a safe bridging role to second allo-HCT in patients with isolated EMR. However, clinical differences between isolated EMR and EMR with BMR remain to be elucidated.

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.

[Emergence of mutation in the colony-stimulating factor 3 receptor gene during follow-up of unclassifiable myeloproliferative neoplasm].

A 25-year-old male with a medical history of stress polycythemia was admitted to a previous hospital for leukocytosis, anemia, and thrombocytopenia. Bone marrow examination revealed left-shifted myeloid hyperplasia without increased blasts and normal male karyotype. No mutations of JAK2, V617F, and colony-stimulating factor 3 receptor gene (CSF3R) were detected. Fluorescence in-situ hybridization for BCR-ABL1 and FIP1L1-PDGFRA were negative. Based on these findings, a diagnosis of an unclassifiable myeloproliferative neoplasm was made, and he was started on hydroxyurea treatment. He was referred to our hospital in April 2016 for transfusion dependence. Bone marrow examination performed at our hospital revealed granulocytic dysplasia and CSF3R T618I was detected. After induction therapy, CSF3R T618I became undetectable, and he went on to undergo allogeneic stem cell transplantation in October 2016. He has been in remission for >4 years posttransplantation. CSF3R T618I is one of the genes responsible for chronic neutrophilic leukemia and atypical chronic myeloid leukemia, suggesting its involvement in the pathogenesis of this case.

Platelets Contribution to Thrombin Generation in Philadelphia-Negative Myeloproliferative Neoplasms: The "Circulating Wound" Model.

Current cytoreductive and antithrombotic strategies in MPNs are mostly based on cell counts and on patient's demographic and clinical history. Despite the numerous studies conducted on platelet function and on the role of plasma factors, an accurate and reliable method to dynamically quantify the hypercoagulability states of these conditions is not yet part of clinical practice. Starting from our experience, and after having sifted through the literature, we propose an in-depth narrative report on the contribution of the clonal platelets of MPNs-rich in tissue factor (TF)-in promoting a perpetual procoagulant mechanism. The whole process results in an unbalanced generation of thrombin and is self-maintained by Protease Activated Receptors (PARs). We chose to define this model as a "circulating wound", as it indisputably links the coagulation, inflammation, and fibrotic progression of the disease, in analogy with what happens in some solid tumours. The platelet contribution to thrombin generation results in triggering a vicious circle supported by the PARs/TGF-beta axis. PAR antagonists could therefore be a good option for target therapy, both to contain the risk of vascular events and to slow the progression of the disease towards end-stage forms. Both the new and old strategies, however, will require tools capable of measuring procoagulant or prohaemorrhagic states in a more extensive and dynamic way to favour a less empirical management of MPNs and their potential clinical complications.

Atypical Chronic Myeloid Leukemia: New Developments from Molecular Diagnosis to Treatment.

Atypical Chronic Myeloid Leukemia, BCR-ABL1 negative (aCML) is a rare hematological entity, included in the group of myelodysplastic (MDS)/myeloproliferative (MPN) overlap syndromes. It is characterized by an aggressive course, a high rate of acute myeloid leukemia (AML) transformation, and a dismal outcome. The clinical presentation includes splenomegaly and leukocytosis with neutrophilia and left-shifted granulocytosis accompanied by granulocytic dysplasia and sometimes multilineage dysplasia. In past years, the disease incidence was likely underestimated, as diagnosis was only based on morphological features. Recently, the improving knowledge in the molecular biology of MDS/MPN neoplasms has made it possible to distinguish aCML from other overlapping syndromes, basing on next generation sequencing. Among the most commonly mutated genes, several involve the Jak-STAT, MAPK, and ROCK signaling pathways, which could be actionable with targeted therapies that are already used in clinical practice, opening the way to tailored treatment in aCML. However, currently, there are few data available for small samples, and allogeneic transplant remains the only curative option for eligible patients.