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Purpose: Chronic myelomonocytic leukemia (CMML) is a rare leukemia characterized by peripheral monocytosis with no disease-modifying therapies. CMML cells are uniquely hypersensitive to granulocyte-macrophage colony-stimulating factor (GM-CSF) and robustly engraft in immunocompromised mice that secrete human cytokines. To leverage these unique biological features, we conducted an integrated human and murine study evaluating ruxolitinib, a JAK1/2 inhibitor that potently downregulates intracellular GM-CSF signaling., Patients and Methods: A total of 50 patients with WHO-defined CMML were enrolled in this open-label, multi-institution phase I/II clinical study, with a ruxolitinib dose of 20 mg twice daily studied in phase II. In parallel, 49 patient-derived xenografts (PDX) derived from 13 study participants were generated and randomized to receive ruxolitinib or vehicle control., Results: The most common grade 3/4 treatment-related toxicities observed were anemia (10%) and thrombocytopenia (6%). The clinical overall response rate was 38% by Myelodysplastic Syndrome/Myeloproliferative Neoplasm (MDS/MPN) International Working Group (IWG) criteria and 43% of patients with baseline splenomegaly achieved a spleen response. Profiling of cytokine levels and somatic mutations at baseline failed to identify predictive biomarkers. PDX models derived from screening samples of study participants recapitulated responses seen in humans, particularly spleen responses, and corroborated ruxolitinib's clinical efficacy in a randomized murine study not feasible in human trials., Conclusions: Ruxolitinib demonstrated clinical efficacy and an acceptable adverse event profile in patients with CMML, identifying a potential novel therapeutic in this rare malignancy. Furthermore, this study demonstrates proof of concept that PDX modeling can recapitulate responses of patients treated on clinical trial and represents a novel correlative study that corroborates clinical efficacy seen in humans. See related commentary by Shastri and Adrianzen-Herrera, p. 6069 ., (©2021 American Association for Cancer Research.)

Chronic myelomonocytic leukemia (CMML) is a rare and challenging type of myeloproliferative neoplasm. Poor prognosis and high mortality, associated predominantly with progression to secondary acute myeloid leukemia (sAML), is still an unsolved problem. Despite a growing body of knowledge about the molecular repertoire of this disease, at present, the prognostic significance of CMML-associated mutations is controversial. The absence of available CMML cell lines and the small number of patients with CMML make pre-clinical testing and clinical trials complicated. Currently, specific therapy for CMML has not been approved; most of the currently available therapeutic approaches are based on myelodysplastic syndrome (MDS) and other myeloproliferative neoplasm (MNP) studies. In this regard, the development of the robust CMML animal models is currently the focus of interest. This review describes important studies concerning animal models of CMML, examples of methodological approaches, and the obtained hematologic phenotypes.

Background: Myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) are associated with cutaneous manifestations. Next-generation sequencing (NGS) is a tool capable of identifying clonal myeloid cells in the skin infiltrate and thus better characterize the link between hematological diseases and skin lesions., Objective: To assess whether skin lesions of MDS/CMML are clonally related to blood or bone marrow cells using NGS., Methods: Comparisons of blood or bone marrow and skin samples NGS findings from patients presenting with MDS/CMML and skin lesions in three French hospitals., Results: Among the 14 patients recruited, 12 patients (86%) had mutations in the skin lesions biopsied, 12 patients (86%) had a globally similar mutational profile between blood/bone marrow and skin, and 10 patients (71%) had mutations with a high variant allele frequency (>10%) found in the myeloid skin infiltrate. Mutations in TET2 and DNMT3A , both in four patients, were the most frequent. Two patients harbored a UBA1 mutation on hematopoietic samples., Limitations: Limited number of patients and retrospective collection of the data. Blood and skin sampling were not performed at the exact same time point for two patients., Conclusion: Skin lesions in the setting of MDS/CMML are characterized by a clonal myeloid infiltrate in most cases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Martin de Frémont, Hirsch, Gimenez de Mestral, Moguelet, Ditchi, Emile, Senet, Georgin-Lavialle, Hanslik, Maurier, Adedjouma, Abisror, Mahevas, Malard, Adès, Fenaux, Fain, Chasset and Mekinian.)

In older patients with chronic myelomonocytic leukaemia (CMML) and limited life expectancy due to age and or comorbidities, it is particularly important to consider the risk of transformation for individualised treatment decisions. There is limited information on potential differences between younger and older CMML patients regarding the cumulative risk of transformation as well as haematological, molecular and biologic characteristics. We analysed data from the Austrian Biodatabase for CMML (ABCMML) to compare these parameters in 518 CMML patients. Categorisation of patients into 3 age-related groups: <60 years, 60-79 years and ≥80 years, showed a significantly lower risk of transformation at higher age by competing risk analysis, with a 4-year risk of 39%, 23% and 13%, respectively (P < .0001). The lower probability of transformation was associated with a lower percentage of blast cells in the peripheral blood (PB) of older patients. Furthermore, we provide a simple score based on age, PB blasts and platelet counts that allowed us to define subgroups of CMML patients with a different cumulative transformation risk, including a low-risk group with a transformation risk of only 5%. Our findings may facilitate reasonable treatment decisions in elderly patients with CMML., (© 2021 The Authors. European Journal of Haematology published by John Wiley & Sons Ltd.)

Purpose of Review: Monocytosis is a distinct but non-specific manifestation of various physiologic and pathologic conditions. Among hematopoietic stem cell neoplasms, depending on the criteria used for disease classification, monocytosis may be a consistent and integral component of diseases such as chronic myelomonocytic leukemia or acute myeloid leukemia with monocytic differentiation, or it may represent an inconsistent finding that often provides a clue to the underlying genetic changes driving the neoplasm. The purpose of this review is to provide the readers with a laboratory-based approach to neoplastic monocytosis., Recent Findings: In-depth elucidation of the genomic landscape of myeloid neoplasms within the past few years has broadened our understanding of monocytosis and its implications for diagnosis and prognosis. Genetic findings also shed light on potential disease response - or lack thereof - to various therapeutic agents used in the setting of myeloid neoplasms. In this review, we provide our approach to diagnose neoplastic monocytosis in the context of case-based studies while incorporating the most recent literature on this topic.

Purpose of Review: For decades, the management of chronic myelomonocytic leukemia (CMML) or juvenile myelomonocytic leukemia (JMML) has been largely inextricable from myelodysplastic syndromes (MDS), myeloproliferative neoplasms, and acute myeloid leukemia. Hallmarks of these diseases have been the emergence of unique genomic signatures and discouraging responses to available therapies. Here, we will critically examine the current options for management and review the rapidly developing opportunities based on advances in CMML and JMML disease biology., Recent Findings: Few clinical trials have exclusively been done in CMML, and in JMML, the rarity of the disease limits wide scale participation. Recent case series in JMML suggest that hypomethylating agents (HMAs) are a viable option for bridging to curative intent with allogeneic hematopoietic stem cell transplant or as posttransplant maintenance. Emerging evidence has demonstrated targeting the RAS-pathway via MEK inhibition may also be considered. In CMML, treatment with HMAs is largely derived from data inclusive of MDS patients, including a small number of patients with dysplastic CMML variants. Based on CMML disease biology, additional therapeutic targets being investigated include inhibitors of splicing, CD123/dendritic cell axis, inherent GM-CSF progenitor cell hypersensitivity, and targeting the JAK/STAT pathway. Current evidence is also expanding for oral HMAs. The management of CMML and JMML is rapidly evolving and clinicians must be aware of the genetic landscape and expanding treatment options to ensure these rare populations are afforded therapeutic interventions best suited to their needs.

Background: Myelomonocytic skewing is considered as a key pathophysiologic phenomenon in chronic myelomonocytic leukemia (CMML), but its prevalence and potential correlation with phenotypic, genotypic, and clinical features are poorly defined., Methods: Skewed differentiation toward the myelomonocytic over erythroid commitment as indicated by an inverse ratio of myelomonocytic/erythroid colonies was investigated in 146 patients with CMML by semisolid in vitro cultures., Results: There was a high prevalence of myelomonocytic skewing in patients with CMML (120/146, 82%); whereas, this phenomenon was rare in normal individuals (1/98, 1%). Patients with CMML with myelomonocytic skewing had higher white blood cell and peripheral blast cell counts, and lower platelet values. The number of mutations in genes of the epigenetic and/or splicing category was higher in CMML patients with as compared with patients without skewing. Patients with myelomonocytic skewing had more frequently mutations in RASopathy genes and higher growth factor independent myeloid colony formation. Interestingly, the lack of myelomonocytic skewing discriminated patients with CMML with a particularly favorable prognosis (60 vs 19 months, P = .003) and a minimal risk of transformation., Conclusion: Myelomonocytic skewing as determined by semisolid cultures can discriminate subgroups of patients with CMML with a different phenotype, a different genotype, and a different prognosis., (© 2021 The Authors. European Journal of Haematology published by John Wiley & Sons Ltd.)

Chronic myelomonocytic leukemia is a clonal chronic hematopoietic disorder that has been classified under the category of Myelodysplastic syndrome/Myeloproliferative neoplasms (MDS/MPN). CMML has high chances of transforming to acute leukemia, however isolated CNS relapse in CMML has never been reported in literature. We report an extremely rare case of a 47 yearold female diagnosed to have CMML- 2 in remission, who developed an isolated central nervous system relapse after matched related allogeneic hematopoietic stem cell transplantation. To our knowledge this is the first report of isolated CNS relapse in CMML post allogeneic stem cell transplant.

Hematolymphoid neoplasms, including lymphoma and myeloid neoplasms, can occur in patients with sickle cell disease (SCD) or equivalent hemoglobinopathy, but an underlying connection between the two conditions has yet to be fully determined. Herein, we report a unique case of sequential development of two separate hematolymphoid neoplasms, human herpes virus 8 (HHV8)-positive diffuse large B-cell lymphoma (DLBCL) and chronic myelomonocytic leukemia, in a 59 year-old African American female with hemoglobin SC disease. While etiology of immunodeficiency is unknown, the potential causes include hydroxyurea therapy, disease related immunomodulation, chronic inflammation, and relatively old age. The leukemia cells demonstrated profound trilineage dysplasia and harbored complex cytogenetic abnormalities with loss of chromosome 5q and 7q, which are often observed in therapy-related myeloid neoplasms. Besides the potential causes listed above, we propose that myeloid leukemia in this setting may result from genomic changes due to excessive hematopoietic replication triggered by a hemolysis-induced cytokine storm. While myeloid neoplasms in the setting of SCD seems to herald a dismal clinical outcome per the literature, the HHV8-positive DLBCL in our case was apparently indolent, opposing the current perception of its clinical outcome., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Chronic myelomonocytic leukemia (CMML) constitutes a hematopoietic stem cell (HSC) disorder characterized by prominent monocytosis and myelodysplasia. Although genome sequencing has revealed the CMML mutation profile, the mechanism of disease development remains unclear. Here we show that aberrant histone acetylation by nucleoporin-98 (NUP98)-HBO1, a newly identified fusion in a patient with CMML, is sufficient to generate clinically relevant CMML pathogenesis. Overexpression of NUP98-HBO1 in murine HSC/progenitors (HSC/Ps) induced diverse CMML phenotypes, such as severe leukocytosis, increased CD115 + Ly6C high monocytes (an equivalent subpopulation to human classical CD14 + CD16 - monocytes), macrocytic anemia, thrombocytopenia, megakaryocyte-lineage dysplasia, splenomegaly, and cachexia. A NUP98-HBO1-mediated transcriptional signature in human CD34 + cells was specifically activated in HSC/Ps from a CMML patient cohort. Besides critical determinants of monocytic cell fate choice in HSC/Ps, an oncogenic HOXA9 signature was significantly activated by NUP98-HBO1 fusion through aberrant histone acetylation. Increased HOXA9 gene expression level with disease progression was confirmed in our CMML cohort. Genetic disruption of NUP98-HBO1 histone acetyltransferase activity abrogated its leukemogenic potential and disease development in human cells and a mouse model. Furthermore, treatment of azacytidine was effective in our CMML mice. The recapitulation of CMML clinical phenotypes and gene expression profile by the HBO1 fusion suggests our new model as a useful platform for elucidating the central downstream mediators underlying diverse CMML-related mutations and testing multiple compounds, providing novel therapeutic potential., (© 2019 by The American Society of Hematology.)

The coexistence of autoimmune disorders (AD) in patients with myelodysplastic syndrome (MDS) or chronic myelomonocytic leukemia (CMML) has been widely recognized, although with distinct results regarding their prevalence and impact on the outcomes of the underlying hematological process. This study was aimed to analyze the prevalence, clinical characteristics, and outcomes of MDS with AD in a series of 142 patients diagnosed with MDS and CMML. AD was ascertained by both the presence of clinical symptoms or compatible serological tests. In total, 48% patients were diagnosed as having AD, being hypothyroidism the most commonly reported clinical AD (8%) and antinuclear antibodies the most frequent serological parameter identified (23.2%). The presence of AD was associated with female gender, lower hemoglobin levels, and higher IPSS-R. Overall survival for patients with AD was inferior to those with no AD (69 vs. 88% at 30 months; HR 2.75, P = 0.008). Notably, clinical but not isolated immune serological parameters had an impact on the outcomes of patients with AD. Finally, in a multivariate analysis, the presence of AD (HR 2.26) along with disease risk categories (very low and low vs. intermediate, high, and very high IPSS-R; HR 4.62) retained their independent prognostic value (P < 0.001). In conclusion, AD are prevalent in MDS and CMML patients and have prognostic implications, especially in lower-risk MDS patients.

Recurrent somatic loss-of-function mutations in histone demethylases are frequently detected in cancer. However, whether loss of a histone demethylase can cause cancer has not been determined. Here, we report that knockout of the histone demethylase Utx in mice causes a chronic myelomonocytic leukemia (CMML)-like disease with splenomegaly, monocytosis, and extramedullary hematopoiesis. Mutational analysis of patient data indicated that UTX mutations occur simultaneously with TP53 mutations in myeloid malignancies, and combined inactivation of Utx and Trp53 accelerated the development of CMML in a cell-autonomous manner. Utx loss caused increased self-renewal of hematopoietic stem cells and predisposed hematopoietic stem cells to differentiate into myeloid-derived lineages. Transcriptome and chromatin immunoprecipitation analyses revealed that Utx activates key transcriptional factors required for erythroid differentiation by modulating histone H3 lysine 27 and lysine 4 trimethylation. Our results suggest that Utx suppresses CMML formation by controlling hematopoietic stem cell self-renewal and differentiation.

Chromosomal abnormalities are detected in 20-30% of patients with chronic myelomonocytic leukemia (CMML) and correlate with prognosis. On the mutation level, disruptive alterations are particularly frequent in chromatin regulatory genes. However, little is known about the consequential alterations in the epigenetic marking of the genome. Here, we report the analysis of genomic DNA methylation patterns of 64 CMML patients and 10 healthy controls, using a DNA methylation microarray focused on promoter regions. Differential methylation analysis between patients and controls allowed us to identify abnormalities in DNA methylation, including hypermethylation of specific genes and large genome regions with aberrant DNA methylation. Unsupervised hierarchical cluster analysis identified two main clusters that associated with the clinical, biological, and genetic features of patients. Group 1 was enriched in patients with adverse clinical and biological characteristics and poorer overall and progression-free survival. In addition, significant differences in DNA methylation were observed between patients with low risk and intermediate/high risk karyotypes and between TET2 mutant and wild type patients. Taken together, our results demonstrate that altered DNA methylation patterns reflect the CMML disease state and allow to identify patient groups with distinct clinical features.

Background: Patients with multiple myeloma (MM) have had significant improvements in outcomes. An increased risk of therapy-related myeloid neoplasms (t-MNs) has also developed. Little is known about the characteristics and outcomes of these patients., Patients and Methods: Patients with MM treated at our institution from 1993 to 2011 were reviewed. Forty-seven patients were diagnosed with t-MN. Our primary objective was to evaluate the interval to t-MN, response to treatment, and overall survival (OS)., Results: The median patient age at the MM diagnosis was 65 years. Of the 47 patients, 32 (68.0%) initially received conventional chemotherapeutic agents, 7 (14.9%), novel agents (eg, lenalidomide, thalidomide, bortezomib), and 8 (17.0%), a combination. Twenty patients (42.6%) underwent high-dose chemotherapy and autologous hematopoietic stem cell transplantation. The median interval from the MM diagnosis to t-MN was 7 years (95% CI, 5.0-28.0). Of the 47 patients, 33 (70.2%) developed therapy-related myelodysplastic syndrome (t-MDS), 11 (23.4%) acute myeloid leukemia (t-AML), and 3 (6.4%) chronic myelomonocytic leukemia (t-CMML). The median age at the t-MN diagnosis was 65 years. Of the 47 patients, 26 (78.8%) with t-MDS, 9 (81.8%) with t-AML, and 1 (33.3%) with t-CMML had complex/high-risk cytogenetics. The median OS for all 47 patients after the t-MN diagnosis was 6.3 months (95% CI, 4.0-8.7)., Conclusion: The development of t-MN in patients with MM is associated with poor outcomes. These patients, in general, have complex cytogenetic abnormalities and short complete remission and OS times. A better understanding of the disease biology and novel therapeutic approaches are warranted., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Familial platelet disorder with a propensity to develop acute myeloid leukemia (FPD/AML) is a rare autosomal dominant disease characterized by thrombocytopenia, abnormal platelet function, and a propensity to develop myelodysplastic syndrome (MDS) and AML. So far, > 20 affected families have been reported. Recently, a second RUNX1 alteration has been reported; however, no additional molecular abnormalities have been found so far. We identified an acquired CBL mutation and 11q-acquired uniparental disomy (11q-aUPD) in a patient with chronic myelomonocytic leukemia (CMML) secondary to FPD with RUNX1 mutation but not in the same patient during refractory cytopenia. This finding suggests that alterations of the CBL gene and RUNX1 gene may cooperate in the pathogenesis of CMML in patients with FPD/AML. The presence of CBL mutations and 11q-aUPD was an important "second hit" that could be an indicator of leukemic transformation of MDS or AML in patients with FPD/AML.

The authors report the results of a hospital-based case-control study of all patients diagnosed with chronic myelomonocytic leukemia (CMML) (n = 36) from 28 participating hospitals over a 4-year period. Diagnoses were made by a single laboratory using 2001 World Health Organization (WHO) criteria. Subjects were matched to 2 control patients and interviewed concerning previous diseases, work histories, and exposures to potential etiologic agents. Peripheral blood and bone marrow findings revealed clinical features of both myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs), consistent with hematopoietic disease category of MDS/MPN. The frequency of clonal cytogenetic abnormalities in all CMML cases was 31%, with no consistent pattern identified. A select number of risk factors associated with occupational exposure, nonoccupational exposure, and prior medical or family history of disease were extracted from the questionnaire. The results were compared between the case and control subjects. A total of 5 study subjects (2 CMML cases and 3 control subjects) were determined to have had some benzene exposure. In addition, none of the highlighted risk factors associated with nonoccupational exposure to etiologic agents was significantly different among the study subjects. These results do not support an increased risk for developing CMML associated with historical exposures to benzene.

Hyperactivation of the transcription factor Stat5 leads to various leukemias. Stat5 activity is regulated by the protein phosphatase SHP-1 in a phospholipase C (PLC)-β3-dependent manner. Thus, PLC-β3-deficient mice develop myeloproliferative neoplasm, like Lyn (Src family kinase)- deficient mice. Here we show that Lyn/PLC-β3 doubly deficient lyn(-/-);PLC-β3(-/-) mice develop a Stat5-dependent, fatal myelodysplastic/myeloproliferative neoplasm, similar to human chronic myelomonocytic leukemia (CMML). In hematopoietic stem cells of lyn(-/-);PLC-β3(-/-) mice that cause the CMML-like disease, phosphorylation of SHP-1 at Tyr(536) and Tyr(564) is abrogated, resulting in reduced phosphatase activity and constitutive activation of Stat5. Furthermore, SHP-1 phosphorylation at Tyr(564) by Lyn is indispensable for maximal phosphatase activity and for suppression of the CMML-like disease in these mice. On the other hand, Tyr(536) in SHP-1 can be phosphorylated by Lyn and another kinase(s) and is necessary for efficient interaction with Stat5. Therefore, we identify a novel Lyn/PLC-β3-mediated regulatory mechanism of SHP-1 and Stat5 activities.

From a retrospective analysis of our series of myelodysplastic patients, we found 16 patients who were initially diagnosed as having a refractory anemia with excess of blasts (RAEB) according to FAB criteria, but later on (median time 4 months, range 2-8) developed a peripheral monocytosis >1 x 10(9)/L, leading to a disease re-classification into a dysplastic type of chronic myelomonocytic leukemia (MD-CMML). Analysis of clinical and prognostic aspects in this subgroup of patients as compared with those of primarily diagnosed MD-CMML patients, showed some significant differences in Hb level, platelet count, percentage of immature circulating precursor (IPC), bone marrow blastosis and trilineage dysplasia. Median survival for present group of patients was 33 months compared with 20 months for MD-CMML. Different prognostic scores were applied for evaluation of risk distribution and relative impact on survival prediction. We suggest on a possible atypical presentation of CMML and indicate a careful attention to be addressed to myelodysplastic patients who develop peripheral monocytosis, who might have a CMML variant, with more favourable prognosis and prolonged survival. Furthermore, we believe this is a further evidence for the arbitrary nature of current classification systems, which definitely exclude CMML from myelodysplastic syndromes.

In 1982, chronic myelomonocytic leukemia (CMML) was first classified in the category of myelodysplastic syndromes (MDSs), but it always seemed somewhat out of place compared with the rest of the MDS categories. In the 1990s, many argued that there were two different forms of CMML, a proliferative type and a myelodysplastic type. Then in 2001 the World Health Organization created a new category called the mixed myelodysplastic/myeloproliferative diseases, under which CMML was included. Although we still do not understand much about CMML pathogenesis nor do we have specific therapies for this disease, at least now most agree that it is in an appropriate category such that other areas of investigation can now proceed. On the other hand, we now understand a great deal of the pathogenesis underlying the disease now called juvenile myelomonocytic leukemia (JMML). JMML also fits in the new category of mixed myelodysplastic/myeloproliferative diseases. JMML is an excellent model malignancy for investigating and understanding dysregulated and aberrant signal transduction in the Ras pathway. It has also served as a teaching tool for exploring inherited predispositions to cancer.

Chronic myelomonocytic leukemia continues to be a poorly understood disease, defined by clinical rather than biological features, with no consensus on optimal therapy. In the past, patients were often assessed for risk using scoring systems developed for other diseases, notably the International Prognostic Scoring System commonly used for myelodysplastic syndrome. The M.D. Anderson Prognostic Scoring System, using hemoglobin, absolute lymphocyte count, peripheral blood immature cells, and bone marrow blasts, was developed specifically for CMML; it was based on retrospective analysis of 213 patients. This report re-examines the validity of this scoring system based on follow-up of the initial cohort and prospectively examines its validity in 250 new patients. Both the original MDAPS system and a modified version derived from data of the initial cohort after extended follow-up (substituting lactate dehydrogenase for bone marrow blasts) effectively stratify both patient cohorts by survival and provide a useful risk assessment tool and additional guidance during treatment decisions.

Neurofibromatosis type 1 (NF1) syndrome is caused by germline mutations in the NF1 tumor suppressor, which encodes neurofibromin, a GTPase activating protein for Ras. Children with NF1 are predisposed to juvenile myelomonocytic leukemia (JMML) and lethally irradiated mice given transplants with homozygous Nf1 mutant (Nf1-/-) hematopoietic stem cells develop a fatal myeloproliferative disorder (MPD) that models JMML. We investigated the requirement for signaling through the GM-CSF receptor to initiate and sustain this MPD by generating Nf1 mutant hematopoietic cells lacking the common beta chain (Beta c) of the GM-CSF receptor. Mice reconstituted with Nf1-/-, beta c-/- stem cells did not develop evidence of MPD despite the presence of increased number of immature hematopoietic progenitors in the bone marrow. Interestingly, when the Mx1-Cre transgene was used to inactivate a conditional Nf1 mutant allele in hematopoietic cells, concomitant loss of beta c-/- reduced the severity of the MPD, but did not abrogate it. Whereas inhibiting GM-CSF signaling may be of therapeutic benefit in JMML, our data also demonstrate aberrant proliferation of Nf1-/-myeloid progenitors that is independent of signaling through the GM-CSF receptor.

The majority of chronic myelomonocytic leukemia (CMML) cases arise de novo; cases evolving from preexisting myelodysplasia (MDS) or myeloproliferative diseases have not been well-studied. We conducted the present study to determine the clinicopathologic features and to study possible underlying molecular and cytogenetic mechanisms involved in this evolution. Between April 1995 and November 2005, we identified 120 CMML cases, of which 20 (16.7%) had a previous diagnosis of MDS. Of the 20 patients with MDS, 6 had relative monocytosis at diagnosis. At the time of MDS to CMML evolution, mutations in JAK2 (V617F), FLT3 (ITD), K-ras-2, or N-ras were not acquired, and only 1 (6%) of 17 evaluable cases showed cytogenetic progression. The median time to evolution from MDS to CMML was 29 months, and the median survival following CMML development was 13 months. Three cases (17%) transformed to acute myeloid leukemia. These findings indicate that in some cases of otherwise typical MDS, the progenitor cells may have some capacity for monocytic proliferation at diagnosis and manifest rapid disease progression once a monocytic proliferation supervenes.

Juvenile myelomonocytic leukemia (JMML) is a lethal disease of young children characterized by hypersensitivity of hematopoietic progenitors to granulocyte-macrophage colony-stimulating factor (GM-CSF). Mutations in PTPN11, which encodes the protein tyrosine phosphatase Shp-2, are common in JMML. We hypothesized that PTPN11 mutations induce hypersensitivity of hematopoietic progenitors to GM-CSF and confer increased GM-CSF-stimulated phospho-extracellular signal-regulated kinase (Erk) levels. To test this hypothesis, the wild-type (WT) and 3 mutant Ptpn11 cDNAs (E76K, D61V, and D61Y) were transduced into murine bone marrow cells to examine GM-CSF-stimulated granulocyte-macrophage colony-forming unit (CFU-GM) growth, macrophage progenitor proliferation, and activation of the Ras signaling pathway. Expression of the Shp-2 mutants induced progenitor cell hypersensitivity to GM-CSF compared with cells transduced with vector alone or WT Shp-2. Macrophage progenitors expressing the Shp-2 mutants displayed both basal and GM-CSF-stimulated hyperproliferation compared with cells transduced with vector alone or WT Shp-2. Consistently, macrophage progenitors transduced with the Shp-2 mutants demonstrated constitutively elevated phospho-Erk levels and sustained activation of phospho-Erk following GM-CSF stimulation compared with vector alone or WT Shp-2. These data support the hypothesis that PTPN11 mutations induce hematopoietic progenitor hypersensitivity to GM-CSF due to hyperactivation of the Ras signaling axis and provide a basis for the GM-CSF signaling pathway as a target for rational drug design in JMML.

Juvenile myelomonocytic leukemia (JMML) is a rare, clonal, mixed myeloproliferative and myelodysplastic disorder afflicting young children. Patients with JMML respond poorly to most standard chemotherapy regimens and, whereas stem cell transplantation is the only known curative approach, even this modality is hampered by high relapse rates. The pathogenesis of JMML arises from dysregulation of signal transduction through the Ras pathway. This dysregulation results in JMML cells demonstrating selective hypersensitivity in vitro to granulocyte macrophage colony-stimulating factor (GM-CSF). Potential causative mutations or other genetic abnormalities in three genes (eg, RAS, neurofibromatosis type 1, and PTPN11), all of which are positioned in the GM-CSF/Ras signal transduction pathway, account for up to 75% of cases of JMML. These pathogenetic advances are paving the way for the development and testing of mechanism-based molecularly targeted therapeutics in JMML aimed specifically at the GM-CSF signal transduction pathway through Ras.

Chronic myelomonocytic leukemia (CMML) is a myeloproliferative disorder with unique characteristics. Dysplasia is usually present in the bone marrow, thus CMML has usually been classified as a myelodysplastic syndrome. The recent World Health Organization classification of myeloid malignancies proposes to classify CMML into a new category of myelodysplastic syndromes and myeloproliferative disorders. A new prognostic score has also been developed exclusively for patients with CMML that recognizes four groups with distinct prognoses. Significant biologic findings in the recent months include the recognition of the importance of angiogenesis in CMML with a possible autocrine role for vascular endothelial growth factor, and the further understanding of the role of tyrosine kinase fusion genes and activation in some patients with CMML Therapeutic discoveries have been hampered by the paucity of studies looking specifically at CMML Among agents with potential significant activity are imatinib mesylate (for patients with platelet-derived growth factor beta receptor-associated fusion genes), hypomethylating agents, antiangiogenic agents, farnesyltransferase inhibitors, and topoisomerase I inhibitors. Future studies should consider CMML as a separate entity to promote a better understanding and identify more effective therapy for patients with this disease.

Background and Objectives: Chronic myelomonocytic leukemia (CMML) is a myelodysplastic syndrome that has been associated with the expression of platelet-derived growth factor b receptor (PDGFRbeta) fusion proteins, namely TEL/PDGFRbeta. These fusion proteins possess a constitutive PDGFRbeta tyrosine kinase activity, leading to aberrant PDGFRbeta signaling and cellular transformation. The expression of PDGFRbeta fusions in CMML could have therapeutic relevance, as PDGFRb is inhibited by the selective tyrosine kinase inhibitor, imatinib. Here, we investigated the possibility of employing imatinib to treat CMML., Design and Methods: We assessed the effect of imatinib on TEL/PDGFRbeta transformed cells in terms of proliferation, by trypan blue exclusion and 3H-thymidine uptake, and TEL/PDGFRbeta autophosphorylation by anti-phosphotyrosine immunoblotting. TEL/PDGFRbeta expression in mononuclear cells from the peripheral blood of 27 clinically diagnosed CMML patients was determined by reverse transcriptase-polymerase chain reaction., Results: Imatinib potently inhibited the proliferation of TEL/PDGFRbeta transformed cells (IC50=7.5 nM), and TEL/PDGFRbeta kinase activity. However, TEL/PDGFRbeta expression was detected in only 1 of 27 CMML patients (4%, confidence intervals: 0-13%). Additionally, another PDGFRbeta fusion protein, Hip1/PDGFRbeta, had a similarly low incidence in the same samples: 1 of 25 (4%, confidence intervals: 0-14%)., Interpretation and Conclusions: Although imatinib represents an attractive therapeutic agent for neoplasias associated with abnormal PDGFRbeta signaling, the low frequency of the TEL/PDGFRbeta and Hip1/PDGFRbeta fusion proteins in CMML suggests that its application to this disease maybe limited. Detection of PDGFRbeta fusion genes in individual patients is necessary in order to employ this drug rationally in CMML.

This report describes the case of an 8-month-old infant with a diagnosis of juvenile myelomonocytic leukemia (JMML) and type 1 neurofibromatosis that presented progression to B lineage acute lymphoid leukemia (ALL). The same rearrangement of gene T-cell receptor gamma (TCR gamma) was detected upon diagnosis of JMML and ALL, suggesting that both neoplasias may have evolved from the same clone. Our results support the theory that JMML may derive from pluripotential cells and that the occurrence of monosomy of chromosome 7 within a clone of cells having an aberrant neurofibromatosis type 1 (NF1) gene may be the cause of JMML and acute leukemia.

The proper expansion and contraction of hematopoietic cells requires tight regulation of cell death. BID, a "BH3-only" molecule, amplifies death receptor signals connecting the extrinsic to intrinsic pathways by triggering the mitochondrial pathway of apoptosis. Bid-deficient mice, as they age, spontaneously develop a myeloproliferative disorder, which progresses from myeloid hyperplasia to a fatal, clonal malignancy closely resembling chronic myelomonocytic leukemia (CMML). Thus, an apoptotic defect can result in myeloid leukemogenesis. Premalignant Bid-/- myeloid precursor cells are resistant to death receptor-induced apoptosis. Furthermore, a competitive reconstitution assay demonstrates that Bid-deficient long-term repopulating cells give rise to expanded myelomonocytic cells in vivo. Surprisingly, a single BH3-only molecule operating in the extrinsic death receptor pathway proved essential in vivo for physiologic cell death required to maintain myeloid homeostasis. Moreover, progression to CMML indicates that an upstream BH3-only molecule, BID, is required to suppress tumorigenesis.

We report an interesting case of chronic myelomonocytic leukemia (CMML) with pentasomy 8q resulting from the duplication of isochromosome 8q in a 47-year-old male. His blood picture and myelogram showed CMML and the chromosome study, using R-banding and G-banding techniques, revealed a karyotype of 47,XY,-8,+i(8)(q10)x2. Dual-color fluorescence in situ hybridization (FISH) studies with a #8 centromeric probe and a locus-specific probe for C-myc gene completely confirmed the result of the conventional cytogenetic method. Reverse transcription polymerase reaction (RT-PCR) revealed no BCR/ABL fusion transcript. Hydroxyurea and 6-mercaptopurine therapy did not induce a complete remission and five months later he died of exacerbation of his disease. On reviewing another two cases with pentasomy 8q in the literature, we feel that pentasomy 8q, when present as a sole anomaly, may play a specific role in leukemogenesis and in determining the clinical characteristics such as monocytic involvement and poor prognosis.

A 51-year-old man was admitted for treatment of severe thrombocytopenia in May 1997. A diagnosis of MDS RA (refractory thrombocytopenia; RTC) was made by bone marrow examination, which revealed mild marrow hypoplasia and a reduced number of megakaryocytes accompanied by micromegakaryocytes and hypolobular megakaryocytes. Chromosome analysis demonstrated 46, XY, t(5;7) (q31;q22) in all 20 cells examined. The patient received only supportive therapy including platelet transfusion, until leukocytosis and monocytosis gradually developed in November 1998. In view of a marked increase in the number of monocytes (more than 3,000/microliter), a diagnosis of CMML was made in December 1998. As the leukocytosis progressed, various inflammatory symptoms such as facial erythema and endophthalmitis developed. Administration of interferon alpha (IFN alpha) unexpectedly worsened the leukocytosis and monocytosis, suggesting abnormal responses of these cells to IFN alpha. Detailed molecular analysis of these cells might reveal a novel mechanism of leukemogenesis associated with 5q31.

An 80-year old man was diagnosed as having immune thrombocytopenic purpura based on epistaxis, purpura and by the platelet count 8 x 10(9)/l. Prednisolone and gamma globulin were administered and the platelet count had been kept around 50 x 10(9)/l during his follow up. Two years from the onset of immune thrombocytopenic purpura he was admitted because of leukocytosis (79 x 10(9)/l with 79% monocytes), anemia and thrombocytopenia. Hypercellular bone marrow with dysplasia of three lineages was observed. In the bone marrow cytogenic analysis, a -6, clonal cytogenic abnormality was observed. 45XY, der(6), t(6;6)(q16;q23). He was diagnosed as having chronic myelomonocytic leukemia. This is a difficult case in which it was diagnosed as refractory thrombocytopenia as a subgroup of myelodysplastic syndrome, rather than immune thrombocytopenic purpura. which might have preceded the development of chronic myelomonocytic leukemia.

Chromosomal abnormalities involving the 11p15 or 11q22-23 bands have been reported in several types of human neoplasms including hematopoietic malignancies. The abnormalities are observed in therapy-related malignancies and less frequently in de novo myeloid malignancies. Abnormality of the MLL gene located on chromosome 11q23 has been well known in therapy-related myeloid malignancies, but it has been reported only recently that the inv(11)(p15q22) in de novo or therapy-related myeloid malignancies results in the fusion of NUP98 on chromosome 11p15 and DDX10 on chromosome 11q22. NUP98 is a nucleoporin that composes the nuclear pore complex and is the target gene in leukemia with the t(7;11)(p15;p15). The DDX10 gene encodes a putative adenosine triphosphate-dependent DEAD box RNA helicase. Here we present another patient with acute myelocytic leukemia (M4) transformed from chronic myelomonocytic leukemia with the inv(11) chromosome who had been treated with etoposide for a germ cell tumor. By reverse transcription polymerase chain reaction (RT-PCR) of the RNA from the leukemic cells of the patient, DDX10-NUP98 and NUP98-DDX10 fusion transcripts were detected. Our case confirms that the inv(11) is a rare chromosomal translocation that is associated with therapy-related or de novo myeloid malignancy and involves NUP98 and DDX10 but not MLL. RT-PCR of the fusion transcripts might be applied to the detection of a small number of leukemic cells in the bone marrow or blood of patients in remission or in the cells harvested for autologous transplantation.

The French-American-British classification of myelodysplastic syndromes (MDS) has contributed greatly to better communication and conduct of clinical trials. However, the advent of novel cytogenetic, immunological and molecular techniques in recent years warrant some alterations to this purely morphological classification. This review aims at highlighting the advances which reflect more closely the unique biological and clinical features of various subtypes of MDS. We propose a comprehensive classification of MDS, to include the newly defined categories, as well as those not included in previous classifications, such as the therapy-induced and hereditary MDS. We hope that this classification will help in focusing attention on the biological features of MDS, the understanding of which will be crucial to combat this disease.

To determine the risk factors of the myelodysplastic syndromes (MDS) we conducted a case-control study in Japan. One hundred and sixteen MDS patients were diagnosed from 1 September to 31 October 1992 and from 1 August to 31 October 1993 in the 32 hospitals enrolled in the idiopathic Disorders of Hematopoietic Organs Research Committee. Age, sex, and hospital-matched controls were selected for each case. Information on cigarette smoking and drinking habits, hair dye use, history of keeping pet animals, and occupational exposures to organic solvents, lead and radiation was obtained from self-administered questionnaires. Conditional logistic regression was applied to this individually matched case-control study and odds ratios (ORs) were computed to estimate association between each exposure variable and risk of MDS. Alcohol drinking was associated with increased risk of MDS (OR = 2.15; 95% confidence interval = 1.12-4.16) and there was a significant trend in risk with increasing amounts of ethanol consumed per week (P < 0.05). We also found elevated ORs for cigarette smokers (OR = 1.80), users of hair dye products (OR = 1.77), and workers exposed to organic solvents (OR = 1.50), although these ratios were not statistically significant. Exposure to pet animals was not associated with risk of MDS. The association observed between alcohol drinking and MDS was still eminent even after adjusted with other variables of cigarette smoking, hair dye use and occupational exposure to organic solvents, and the dose-response relationship was also confirmed.

A 70-year-old male was admitted because of anemia in September 1989, and primary myelofibrosis was diagnosed based on the presence of leukoerythroblastosis, a normal chromosomal analysis and pathological findings of fibrosis in bone marrow. Although he was anemic, he did not require any treatment for two years. Then his hematological status deteriorated to severe pancytopenia, and the marrow biopsy revealed marked hypoplasia with fatty replacement and scattered fibrosis. He was treated with metenolon without success and frequent transfusion of packed red cell was required. This hypoplastic status continued for seven months. In May 1992 his WBC count increased gradually with monocytosis. The marrow was filled with various stages of monocytes, with almost no fibrosis remaining. The chromosomal analysis was repeated but disclosed no abnormalities, consistent with the negative result of BCR-ABL rearrangement investigated by the RT-PCR method. One month later, when the patient died of multiple cerebral bleeding and infection, the leukocyte count exceed 90,000/microliters. It is known that major causes of death for patients with primary myelofibrosis are infection, bleeding, cardiac trouble and transformation to leukemia. We describe a case of myelofibrosis who developed to chronic myelomonocytic leukemia following severe aplastic phase.

A 5-year-old girl was diagnosed as having idiopathic thrombocytopenic purpura (ITP) based on symptoms of nasal bleeding and purpura. The platelet count was 35,000/microliters without anemia or leukopenia. Micromegakaryocytes were observed in normocellular bone marrow without dyserythropoiesis or dysgranulopoiesis. She had periosteal fibroma of the rib and atopic dermatitis with elevated serum IgE. Prednisolone and azathioprine were administered but with no response. The cumulative dose of azathioprine was 20 g for 28 months. Nine years after the diagnosis of ITP, she was admitted because of dyspnea and anemia. The white cell count was 26,900/microliters with 17% monocytes. The hemoglobin was 3.9 g/dl and the platelet count was 9,000/microliters. Dyserythropoiesis, dysgranulopoiesis and micromegakaryocytes were observed in hypercellular bone marrow. The chromosome analysis demonstrated 47, XX, +21. She was diagnosed as having chronic myelomonocytic leukemia (CMMoL) and received bone marrow transplantation (BMT) from an HLA-identical sibling conditioned with high-dose busulfan and melphalan. After 17 months of remission, the disease recurred with an abnormal karyotype of 47, XX, +21, 7q+. Despite a second BMT conditioned with high-dose etoposide, cyclophosphamide and total body irradiation, she died of the disease. Refractory thrombocytopenia as a subgroup of myelodysplastic syndrome, rather than ITP, might have preceded the development of CMMoL, with the possibility of azathioprine-induced leukemia.

Monosomy 7 myelodysplasia is a rare hematological entity and is associated with morphological abnormalities in bone marrow and peripheral smear, and poor prognosis in children. We describe 2 children with infantile monosomy 7 myelodysplasia which evolved to leukemia. One of them died after 1 month, and the other is still on therapy for acute myelocytic leukemia (M4) which has evolved from chronic myelomonocytic leukemia. We concluded that chromosomal analysis must be done routinely in patients with myelodysplasia, in acute myeloid leukemia and chronic myelomonocytic leukemia.

The authors report an unusual case of myelodysplastic syndrome (MDS) associated with relapsing polychondritis (RP), which developed at almost the same time as MDS. The initial diagnosis was MDS, refractory anemia (RA) subtype, according to the FAB classification. Symptoms of RP were apparently controlled by oral administration of prednisolone (PSL), although MDS was not. Within 1 month after the diagnosis, monocytosis and thrombocytopenia without excess of blasts became prominent and transformation from RA to chronic myelomonocytic leukemia (CMML) was recognized. Combination chemotherapy including daunorubicin (DNR) and cytosine arabinoside (ara-c) did not subdue the progressive monocytosis and thrombocytopenia. Finally, the patient died of pulmonary hemorrhage 3 months after the onset of the disease. The prognosis of MDS may be poorly influenced by association with RP.

A 46-year-old man treated with azathioprine (100-150 mg/day) and prednisolone (10mg/day) for 14 years after allogeneic renal transplantation, was admitted to our hospital in December, 1988 for the evaluation of leukocytosis. His leukocyte count was 32,700/microliters with 38% monocytes and 2% blasts. Chromosomal analysis of the bone marrow revealed 45, XY, -7. He was diagnosed as chronic myelomonocytic leukemia (CMML), and treated with low-dose Ara-C. Two months later, he progressed to overt acute leukemia, and he complained of difficulty in swallowing. Endoscopic examination revealed esophageal cancer. The patient died of respiratory failure on April 18, 1989. This case suggests that immunosuppressive agents might play an important role on the pathogenesis of CMML and esophageal cancer.

A patient with a myeloproliferative disorder is described with an eosinophilia together with T-cell lymphoma. A unique translocation t(8;13)(p11.2;q12) was present in all bone marrow cells examined at presentation. No evidence of this translocation was found in a peripheral blood lymphocyte culture. Chromosome analysis after 9 months revealed this same translocation as well as an extra chromosome 21 in all cells; 4.5% of cells also had an additional chromosome 9. The morphologic diagnosis at this stage was chronic myelomonocytic leukemia. Immunophenotyping 3 months later was consistent with a stem-cell leukemia.

We report a case of chronic myelomonocytic leukemia (CMMoL) with unusual features and an isochromosome 14q as the sole abnormality. A review of the literature suggests that isochromosome 14q (or trisomy 14) is a marker of leukemia with dysplastic features.

The prognostic significance of clonal karyotype status in myelodysplastic syndrome (MDS) is assessed after an extended follow-up period of 5 years. There are three karyotype, single abnormalities or multiple abnormalities at the time of referral. However, there is no correlation between the size of the abnormal clone and prognosis. Karyotype status has independent prognostic significance in 'high risk' MDS so that patients with a refractory anaemia with excess of blasts (RAEB)/RAEB in transformation (RAEB-t) and a normal karyotype survive significantly longer than those with an abnormal karyotype (P < 0.001) and do not differ significantly from patients with refractory anaemia (RA). Significant differences in survival according to karyotype status are also seen in patients with chronic myelomonocytic leukaemia (P < 0.001) but not in those with primary acquired sideroblastic anaemia and RA. Among patients studied sequentially, those who retained a normal karyotype survived significantly longer than those who developed an abnormality on follow-up (P < 0.001). The risk of leukaemic transformation was also increased in patients who presented with or subsequently developed a clonal karyotype abnormality compared with those who remained normal (P < 0.05).

Background: Clinical and cytogenetic analyses were performed in 97 patients with myelodysplastic syndromes (MDS) to evaluate risk factors for poor prognosis., Methods/results: Among them, 22 patients survived for less than 1 year: 10 of these had complex chromosomal abnormalities (complex aberrations), but only 5 of the remaining 75 patients who survived longer than 12 months did. Leukemia did not develop in approximately half of the patients who died within 1 year. The occurrence rate of leukemic transformation appears to depend on MDS subtypes rather than cytogenetic changes. In contrast, the percentage of patients who survived for less than 1 year is related to chromosomal changes, especially to complex aberrations. Of particular interest in this study is that 7 of 11 patients with MDS who had myelofibrosis survived for less than 1 year, and 5 of 7 patients with secondary MDS were included in this group showing a poor prognosis. By hematologic analysis, significant differences were found in the hemoglobin values and platelet counts of patients who survived for less than 1 year., Conclusions: From this analysis, three major risk factors for a poor prognosis were identified: complex aberrations, a history of chemotherapy or radiation therapy (secondary MDS), and development of myelofibrosis. The survival probability in the patients with MDS having at least one of these three factors was significantly low when compared with that in patients without these factors, indicating that cytogenetic analysis in combination with observance of certain clinical manifestations is important in therapeutic management of patients with MDS.

Two patients with acute myeloid leukemia (AML) developed a chronic myelomonocytic leukemia (CMMoL)-like state after chemotherapy. Both patients showed morphological evidence of myelodysplasia together with acute leukemia at presentation (Case 1: M5b with trilineage myelodysplasia and Case 2: M4 with dysmegakaryocytopoiesis). They also showed persistent monocytosis without prominent blast cell proliferation after induction therapy. The possibility was suggested that these two patients were in acute transformation from CMMoL at presentation and returned to a CMMoL-like state after induction therapy.

Philadelphia chromosome (Ph)-negative chronic myelogenous leukemia (CML) and chronic myelomonocytic leukemia (CMML) are heterogeneous disorders characterized by various degrees of proliferation, dysplasia, maturation arrest, and monocytosis. In this article, the clinical, laboratory, molecular, and therapeutic aspects of the disease entities are reviewed.