Chronic myelomonocytic leukaemia: a concise clinical and pathophysiological review.

Chronic myelomonocytic leukaemia (CMML) is a clonal haematopoietic stem cell disorder with myelodysplastic and myeloproliferative overlap features, and an inherent tendency to transform to acute myeloid leukaemia. Approximately 30% of patients present with clonal cytogenetic abnormalities, while almost 90% have molecular aberrations involving epigenetic regulation, the spliceosome component machinery, tumour suppressor genes and transcription factors/regulators. Numerous prognostic models exist for CMML, with more recent models incorporating prognostic mutations, such as those involving ASXL1. Other variables that seem to consistently affect outcomes include the degree of leucocytosis/monocytosis, anaemia and thrombocytopenia. Allogeneic stem cell transplant remains the only curative option for CMML, while hypomethylating agents can be used for transplant-ineligible patients or those without suitable stem cell sources. Targeting biological pathways activated in CMML offers potential hope for more effective and less toxic therapies.

Chronic myelomonocytic leukemia: 2013 update on diagnosis, risk stratification, and management.

DISEASE OVERVIEW: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder that is classified as a myelodysplastic/myeloproliferative neoplasm by the 2008 World Health Organization classification of hematopoietic tumors. It is characterized by absolute monocytosis (>1 × 109/L) in the peripheral blood that persists for at least 3 months. DIAGNOSIS: The diagnosis of CMML rests on a combination of morphologic, histopathologic and chromosomal abnormalities in the bone marrow. It is important to exclude other myeloproliferative neoplasms and infectious/autoimmune conditions that can cause monocytosis. RISK STRATIFICATION: Several CMML-specific prognostic models incorporating novel mutations have been recently reported. The Mayo prognostic model classified CMML patients into three risk groups based on: increased absolute monocyte count, presence of circulating blasts, hemoglobin <10 gm/dL and platelets <100 × 109/L. The median survival was 32 months, 18.5 months and 10 months in the low, intermediate, and high-risk groups, respectively. The Groupe Francophone des (GFM) score segregated CMML patients into three risk groups based on: age >65 years, WBC >15 × 109/L, anemia, platelets <100 × 109/L, and ASXL1 mutation status. After a median follow-up of 2.5 years, survival ranged from not reached in the low-risk group to 14.4 months in the high-risk group. RISK-ADAPTED THERAPY: The Food and Drug Administration has approved azacitidine and decitabine for the treatment of patients with CMML. An allogeneic stem cell transplant can potentially offer a curative option to a subset of CMML patients. It is hoped that with the discovery of several novel mutations, targeted therapies will become available in the near future.

Adult leukemic synovitis is associated with leukemia of monocytic differentiation.

BACKGROUND: Leukemic synovitis is a rare complication of adult myeloid leukemias characterized by joint pain and swelling. It is important to recognize this diagnostic challenge as it may be the initial manifestation of leukemia or of relapse. METHODS: A retrospective search of patient files from 2 teaching hospitals identified 4 adult patients who presented with large joint arthritis and concurrent or subsequent leukemic synovitis. All patients presented with inflammatory arthritis of large joints, and leukemic synovitis was identified by the presence of leukemic cells in the synovial fluid or infiltrating the synovial membrane seen at biopsy. RESULTS: A leukemia of monocytic origin-acute myelomonocytic leukemia or chronic myelomonocytic leukemia-was diagnosed in all 4 patients. In 2 cases, leukemic synovitis was the initial manifestation of leukemia. In the third case, it was the first sign of relapse, and in the remaining case, it developed shortly after diagnosis of leukemia. All patients had either osteoarthritis or rheumatoid arthritis. One patient was diagnosed simultaneously with osteoarthritis and leukemia. The remaining patients had a prior history of arthritis. CONCLUSIONS: Adult leukemic synovitis occurs in association with leukemias of monocytic differentiation. Data presented here, and review of isolated case reports, support this association. The finding of large joint arthritis as a comorbidity in these 4 cases raises questions about the role of antecedent arthritis as a predisposing factor in the pathophysiology of leukemic synovitis.

Lipoid pneumonia with chronic myelomonocytic leukemia.

A case of lipoid pneumonia with chronic myelomonocytic leukemia is reported. A 61-year-old man was autopsied after suffering from myelodysplastic syndrome (chronic myelomonocytic leukemia) for 13 years. Interstitial lesions of the lungs were suspected as infiltration of leukemia cells before the autopsy. However, blastic leukemia cells were not observed in the lung, although they were seen in the bone marrow and spleen at autopsy. Instead, an unusual amount of cholesterol deposits was observed with mucormycosis and aspergillosis in the lungs. Cholesterol deposition was observed not only in perihilar but also in subpleural regions without apparent bronchial obstruction in both lungs. It is thought that malfunction of monocytes/macrophages resulted in repeated fungal infection and storage of cholesterol caused by tissue destruction and impaired tissue repairing.

Ocular infiltration as initial presentation of acute monocytic leukaemia transformed from chronic myelomonocytic leukaemia associated with BRAF V600E mutation.

Acute monocytic leukaemia (French-British-American classification: AML-M5b) is characterised by a predominance of cells of the monocytic lineage on bone marrow examination. Furthermore, a discerning feature is its tendency for tissue infiltration. While gum hypertrophy and hepatosplenomegaly are common, ocular involvement is rare. Here, we present a case of a 75-year-old man referred with proptosis and monocytosis-subsequently diagnosed as AML-M5b, whose disease course was distinguished by extensive tissue invasion (ocular, pulmonary, liver, spleen). Cytogenetics and molecular tests were consistent with blastic transformation of previously undiagnosed chronic myelomonocytic leukaemia, supported by the presence of long-standing, low-grade monocytosis. Notably, a BRAF V600E mutation was also detected-an oncogenic driver previously reported in de novo and therapy-related, but not chronic myelomonocytic leukaemia-transformed, AML-M5b. While an initial response to cytoreductive treatment was observed, his tissue-invasive disease soon progressed with worsening pulmonary infiltrates, disseminated intravascular coagulation and renal failure, resulting in death.

Genome-wide single-nucleotide polymorphism analysis in juvenile myelomonocytic leukemia identifies uniparental disomy surrounding the NF1 locus in cases associated with neurofibromatosis but not in cases with mutant RAS or PTPN11.

Juvenile myelomonocytic leukemia (JMML) is a malignant hematopoietic disorder whose proliferative component is a result of RAS pathway deregulation caused by somatic mutation in the RAS or PTPN11 oncogenes or in patients with underlying neurofibromatosis type 1 (NF-1), by loss of NF1 gene function. To search for potential collaborating genetic abnormalities, we used oligonucleotide arrays to analyse over 116 000 single-nucleotide polymorphisms across the genome in 16 JMML samples with normal karyotype. Evaluation of the SNP genotypes identified large regions of homozygosity on chromosome 17q, including the NF1 locus, in four of the five samples from patients with JMML and NF-1. The homozygous region was at least 55 million base pairs in each case. The genomic copy number was normal within the homozygous region, indicating uniparental disomy (UPD). In contrast, the array data provided no evidence for 17q UPD in any of the 11 JMML cases without NF-1. We used array-based comparative genomic hybridization to confirm 17q disomy, and microsatellite analysis was performed to verify homozygosity. Mutational analysis demonstrated that the inactivating NF1 lesion was present on both alleles in each case. In summary, our data indicate that a mitotic recombination event in a JMML-initiating cell led to 17q UPD with homozygous loss of normal NF1, provide confirmatory evidence that the NF1 gene is crucial for the increased incidence of JMML in NF-1 patients, and corroborate the concept that RAS pathway deregulation is central to JMML pathogenesis.

Opioid toxicity with underlying tumour lysis syndrome in a patient with CMML: a diagnostic and therapeutic challenge.

Use of strong opioids like morphine as analgesics for painful conditions in haematological malignancies is a challenging task. We report a unique case of chronic myelomonocytic leukaemia presenting with opioid toxicity overlapping with tumour lysis syndrome. The patient was on hydroxyurea-based chemotherapy for the primary disease. She was receiving oral morphine for abdominal pain due to splenomegaly. She was brought to the emergency in unresponsive state with pinpoint pupils. Opioid overdose leading to unconsciousness was suspected as the first diagnosis. Further workup revealed a final diagnosis of tumour lysis syndrome overlapping with opioid overdose. The patient was ventilated and started on naloxone infusion, and supportive measures for managing tumour lysis were added. The patient gradually improved and was extubated on the fifth day of ventilation. This case presents several learning points for the treating physician. Haematological malignancies have a dynamic course of disease with waxing and waning tumour burden during the course of chemotherapy. This fact should be kept in mind when prescribing strong opioids like morphine on outpatient basis to these patients. Massive tumour cell lysis during the course of chemotherapy may precipitate tumour lysis syndrome and may lead to renal dysfunction which makes the patient susceptible to morphine-related adverse effects. Pain physician should keep a watch for therapy-related adverse effects to avoid diagnostic and therapeutic dilemma associated with coexisting features of these two fatal conditions.

Transformation of cytogenetically normal chronic myelomonocytic leukaemia to an acute myeloid leukaemia and the emergence of a novel +13, +15 double trisomy resulting in an adverse outcome.

A 58-year-old man was admitted with symptoms of lethargy and easy bruising for four months duration. Peripheral blood (PB) analysis revealed a white blood cell count (WBC) of 15.9 x 10(9)/l with monocytes 5.4 x 10(9)/l. Bone marrow (BM) was hypercellular with 15% blasts, monocytosis and trilineage dysplasia. Conventional cytogenetic analysis (G-banding) detected an apparently normal male karyotype (46,XY). A diagnosis of chronic myelomonocytic leukaemia (CMML) was made. After 3 years, PB analysis revealed a WBC count of 22 x 10(9)/l and a predominance of blasts. BM aspirate analysis also revealed 89% myeloid blasts and G-banding detected the emergence of an abnormal clone harbouring an extra copy of chromosomes 13 and 15. A diagnosis of disease transformation to acute myeloid leukaemia (AML) was made. Post chemotherapy BM aspirate was very hypocellular and the abnormal +13, +15 clone was still present suggesting primary refractory disease. A second course of chemotherapy was only administered for 24 hours due to complications. The abnormal +13, +15 clone was still present and it was decided that no further treatment apart from palliative care could be offered. The patient died 11 weeks later, five months after AML transformation. This is the first description of a cytogenetically normal CMML patient transforming to AML with the emergence of a unique +13, +15 double trisomy resulting in an adverse outcome.

The Tel-PDGFRbeta fusion gene produces a chronic myeloproliferative syndrome in transgenic mice.

Chronic myelomonocytic leukemia (CMML) is a pre-leukemic syndrome that displays both myelodysplastic and myeloproliferative features. The t(5;12) chromosomal translocation, present in a subset of CMML patients with myeloproliferation fuses the amino terminal portion of the ets family member, Tel, with the transmembrane and tyrosine kinase domains of platelet-derived growth factor receptor beta (PDGFRbeta) gene. To investigate the role of this fusion protein in the pathogenesis of CMML, we expressed the Tel-PDGFRbeta fusion cDNA in hematopoietic cells of transgenic mice under the control of the human CD11a promoter. Transgenic founders and their offspring express the transgene specifically in hematopoietic tissues and develop a myeloproliferative syndrome characterized by: overproduction of mature neutrophils and megakaryocytes in the bone marrow; splenomegaly with effacement of splenic architecture by extramedullary hematopoiesis; an abnormal population of leukocytes co-expressing lymphoid and myeloid markers; and increased numbers of colonies in in vitro bone marrow CFU assays. All mice expressing the transgene exhibited at least one of these features of dysregulated myelopoiesis, and 20% progressed to a myeloid or lymphoid malignancy. This murine model of CMML parallels a myeloproliferative syndrome in humans and implicates the Tel-PDGFRbeta fusion protein in its pathogenesis.

A case of type B lactic acidosis as a complication of chronic myelomonocytic leukaemia: a case report and review of the literature.

INTRODUCTION: Type B lactic acidosis represents a rare and often lethal complication of haematological malignancy. Here, we present a patient who developed a type B lactic acidosis presumably due to a concurrent chronic myelomonocytic leukaemia. Upon swift initiation of cytoreductive chemotherapy (doxorubicin), the lactic acidosis was rapidly brought under control. This case adds to the literature reporting other haematological malignancies that can cause a type B lactic acidosis and its successful treatment. CASE PRESENTATION: We report the case of a 77-year-old Caucasian man brought to our Accident and Emergency department following an unwitnessed collapse; he was found surrounded by coffee-ground vomit. Although haemodynamically stable on admission, he rapidly deteriorated as his lactic acid rose. An initial arterial blood gas revealed a pH of 7.27 and lactate of 18mmol/L (peaking at 21mmol/L). CONCLUSIONS: A high degree of clinical suspicion for haematological malignancy should be held when presented with a patient with lactic acidosis in clinical practice, even without evidence of poor oxygenation or another cause. Treatment with emergency chemotherapy, in lieu of a definitive diagnosis, was rapidly successful at lowering lactate levels within 8 hours. This may suggest a causal and perhaps direct relationship between lactic acid production and the presence of leukemic cells. Veno-venous haemofiltration had no apparent effect on reducing the lactic acidosis and therefore its benefit is questioned in this setting, especially at the cost of delaying chemotherapy. In the face of a life-threatening lactic acidosis, pragmatic clinical judgement alone may justify the rapid initiation of chemotherapy.

Diverse effects of tumor necrosis factor-alpha on three subclones from human myelomonocytic leukemia cell line ME-1 exhibiting different differentiation stages.

The effects of tumor necrosis factor-alpha (TNF-alpha) were examined in three subclone cells from human myelomonocytic leukemia cell line ME-1. These three subclone cells exhibit different differentiation stages of the myelomonocytic lineage. TNF-alpha exerted a growth-suppressive effect on the least mature subclone cells, ME-F2 cells. On the other hand, TNF-alpha induced the most mature ME-F1 cells and intermediate ME-F3 cells to differentiate along the monocytic pathway. TNF-alpha also enhanced interferon-gamma (IFN-gamma)-induced complement C2 production by ME-F1 and ME-F3 cells but did not affect production by differentiated ME-F1 and ME-F3 cells. These results suggest that the diversity of the effects of TNF on subclone cells from ME-1 depends on the stage of cell differentiation.

Clinical features of MDS.

MDS is primarily a disease of the elderly. Cases who give a history of exposure to X-rays, cytotoxic drugs or leukaemogenic chemicals may be younger. Many cases of MDS present because of an incidental blood count. The most prominent clinical features are those of anaemia, neutropenia, thrombocytopenia. Because haemopoietic tissue is also dysfunctional the pathological effect is often greater than the figures would suggest, even leading to infection of bleeding with normal neutrophil or platelet counts. Occult abscesses are a particular feature. Despite documented abnormalities of the lymphoid system, neither infections characteristic of T-cell immunodeficiency nor autoimmunity is a problem. The proliferation of monocytes in CMML leads to organomegaly, leukaemia cutis, serous effusions and vasculitic lesions caused by the mishandling of circulating immune complexes. Cancer is no commoner than in age-matched controls, but coincident lymphoid tumours do occur. Many patients require long-term blood transfusion and will run into problems of iron overload unless precautions are taken.

All trans retinoic acid abrogates spontaneous monocytic growth in juvenile chronic myelomonocytic leukaemia.

INTRODUCTION: All trans retinoic acid, the active metabolite of vitamin A, exerts profound effects on cell differentiation. On normal myeloid progenitors, retinoids switch the differentiation program of granulo-macrophagic progenitors towards the granulocytic lineage and consequently reduce CFU-M colony formation. Bone marrow and peripheral blood mononuclear cells from children with Juvenile Chronic Myelomonocytic Leukaemia show typical spontaneous monocytic growth. We questioned whether in this disease, retinoids could switch myelomonocytic growth and inhibit the abnormal CFU-M colony proliferation. METHODS: Ten JCML samples were studied in the presence of ATRA in methyl cellulose colony assay, before (CFU-C) or after (pre-CFU) liquid suspension culture. RESULTS: In vitro characteristics of JCML such as spontaneous monocytic growth in the absence of growth factor was noted in all patients. In the presence of leucocyte-conditioned medium, nine samples showed only CFU-M growth and one sample CFU-GM growth. Incubation with ATRA inhibited CFU-M colony formation in nine cases. Enhancement of granulocytic differentiation (CFU-G) was noted in nine cases. ATRA also inhibited CD34+ JCML monocytic growth and GM-CSF hypersensitivity. CONCLUSION: These data suggest that, in JCML progenitors, retinoid pathways are functional and inhibition of immature monocytic progenitors cells may be achieved with retinoids, without impeding granulocytic cell growth.

Philadelphia chromosome-negative chronic myelogenous leukemia and chronic myelomonocytic leukemia.

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.

Priming effects of macrophage colony-stimulating factor on monocytic leukemia cells in combination with chemotherapy: induction of programmed cell death in vivo.

Two elderly patients with chronic myelomonocytic leukemia were treated with cytosine arabinoside (Ara-C) and aclarubicin (ACR) under simultaneous administrations of macrophage colony-stimulating factor (M-CSF) (CAM), and both obtained good responses. Examination of apoptosis using flow cytometry revealed induction of apoptotic death of leukemia cells by CAM in Patient 2, while neither induction of apoptotic death of leukemia cells nor clinical response were seen with CAG (Ara-C, ACR, and granulocyte colony-stimulating factor) given prior to CAM in Patient 1. These findings suggested that chemotherapy combined with simultaneous administration of M-CSF could effectively reduce monocytic leukemia cells by inducing programmed cell death.

[Clinical biological features of mixed myeloid diseases]. / Kliniko-biologicheskie osobennosti smeshannykh mieloidnykh zabolevanii.

AIM: To characterize patients with mixed myeloid neoplasias with proliferation of neutrophils, platelets and eosinophils. MATERIAL AND METHODS: Examination and treatment results were analysed for patients with atypical myeloid leukemia (n = 4), myelodysplastic syndrome (MDS, n = 1) and thrombocytosis, MDS and eosinophilia (n = 1). The examination included morphological, histological, cytogenetic and molecular tests. RESULTS: One patient with atypical chronic myeloid leukemia was prior diagnosed to have primarily MDS with a typical aberration of chromosome 5. Two other patients had an initial morphological picture of resistant anemia with blast excess, signs of myeloproliferation and extramedullary hemopoiesis. One and two months after the first examination they received transfusions of erythrocytic mass. Just then they were found to have splenomegaly and leukocytosis due to proliferating and maturating forms of neutrophils. The course of the disease in patients with MDS, thrombocytosis and normal karyotype and in patients with MDS, eosinophilia and combined chromosomal breaks including translocation (3;12)(q21;p13) was characterized by resistance to standard programs of polychemotherapy and transformation into acute myeloblastic leukemia. CONCLUSION: In some cases atypical CML is a stage of a natural course of MDS. Some MDS variants with eosinophilia and thrombocytosis should be referred to the group of mixed myeloid neoplasias.

[Hemopoiesis in chronic myelomonocytic leukemia]. / Gemopoéz pri khronicheskom mielomonotsitarnom leikoze.

Hemopoiesis and functional activity of monocytes were assessed in 30 patients with chronic myelomonocytic leukemia (CMML). Changes in haemogram in CMML are characterized by anemia, thrombocytopenia, normal or increased count of leukocytes with absolute monocytosis and increased count of young granulocytes. Bone marrow hemopoiesis is characterized by enhanced proliferation of cellular elements of granulocytopoiesis and monocytes, suppressed erythropoiesis and megakaryocytopoiesis. Dysplastic changes are most expressed in the erythrocytic stem cells. Studies of lysosomal enzymes showed their increased activity in monocytes of CMML patients.

Lenalidomide and metronomic melphalan for CMML and higher risk MDS: a phase 2 clinical study with biomarkers of angiogenesis.

Metronomic, low dose chemotherapy may have anti-angiogenic effects and augment the effects of lenalidomide in MDS and CMML. We evaluated the clinical efficacy, tolerability and anti-angiogenic effects of melphalan 2mg and lenalidomide 10mg for 21 days/28 in CMML (n=12) and higher risk MDS (n=8) patients in a prospective phase II study. The primary endpoint was overall response and secondary endpoints included survival, progression-free survival, toxicity and biomarkers of angiogenesis. The median age was 73 years, 55% were pretreated and transfusion dependent. The overall response rate was 3(15%) of 19 evaluable patients but 25% in CMML and 33% in pCMML. Dose reductions and/or delays were common due to myelosuppression. Transient spikes in circulating endothelial cells that declined below baseline were seen in responders and patients with CMML, suggesting anti-angiogenic activity. In conclusion, lenalidomide and metronomic low dose melphalan demonstrate signals of clinical and possible anti-angiogenic activity in patients with pCMML that require future validation. This trial was registered at clinicaltrial.gov under # NCT00744536.

An evolutionary perspective on chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) shares with other myeloid diseases a number of somatic gene mutations. These mutations can now be integrated within the framework of evolution theory to address the mechanisms of the disease. Several evidences indicate that the disease emerges in adult hematopoietic stem cells (HSC) through the age-dependent accumulation of DNA damage, leading stochastically to a driver mutation that confers a competitive advantage to the cell. A mutation in TET2 gene could be one of these driver mutations provoking the emergence of clonality. After a long latency, secondary lesions, such as mutations in the SRSF2 gene, contribute to progression to full-blown malignancy, with abnormal differentiation. Additional mutations accumulate and branching arising mostly through mitotic recombination generates clonal heterogeneity. Modifications in the microenvironment probably affect this clonal dynamics, whereas epigenetic alterations, such as hypermethylation of the TIF1γ gene promoter, may generate phenotypic diversification of otherwise clonal populations. The preserved although deregulated myeloid differentiation that characterizes CMML, with granulomonocyte expansion and various cytopenias, may depend on early clonal dominance in the hematopietic cell hierarchy. Progression to acute myeloid leukemia observed in 25-30% of the patients may arise from the massive expansion of a clone with novel genetic lesions, providing a high fitness to previously minor subclones when in chronic phase of the disease. This review discusses the various models of disease emergence and progression and how this recent knowledge could drive rational therapeutic strategies.