Childhood Myelodysplastic Syndrome: Focus on the Approach to Diagnosis and Treatment of Juvenile Myelomonocytic Leukemia

Hematology ◽  
2010 ◽  
Vol 2010 (1) ◽  
pp. 357-362 ◽  
Author(s):  
Mignon L. Loh
Keyword(s):  
Germ Line ◽  
Myeloproliferative Neoplasms ◽  
Standard Of Care ◽  
Mitogen Activated Protein Kinase ◽  
Juvenile Myelomonocytic Leukemia ◽  
Cell Transplant ◽  
Current Standard ◽  
Hematopoietic Stem ◽  
Mitogen Activated Protein ◽  
Myelomonocytic Leukemia

AbstractExpansion of myeloid blasts with suppression of normal hematopoiesis is a hallmark of acute myeloid leukemia (AML). In contrast, myeloproliferative neoplasms (MPNs) are clonal disorders characterized by overproliferation of one or more lineages that retain the ability to differentiate. Juvenile myelomonocytic leukemia (JMML) is an aggressive MPN of childhood that is clinically characterized by the overproduction of monocytic cells that can infiltrate organs, including the spleen, liver, gastrointestinal tract, and lung. Major progress in understanding the pathogenesis of JMML has been achieved by mapping out the genetic lesions that occur in patients. The spectrum of mutations described thus far in JMML occur in genes that encode proteins that signal through the Ras/mitogen-activated protein kinase (MAPK) pathways, thus providing potential new opportunities for both diagnosis and therapy. These genes include NF1, NRAS, KRAS, PTPN11, and, most recently, CBL. While the current standard of care for patients with JMML relies on allogeneic hematopoietic stem-cell transplant, relapse is the most frequent cause of treatment failure. Rarely, spontaneous resolution of this disorder can occur but is unpredictable. This review is focused on the genetic abnormalities that occur in JMML, with particular attention to germ-line predisposition syndromes associated with the disorder. Current approaches to therapy are also discussed.

scholarly journals How I treat juvenile myelomonocytic leukemia

Blood ◽  
2015 ◽  
Vol 125 (7) ◽  
pp. 1083-1090 ◽  
Author(s):  
Franco Locatelli ◽  
Charlotte M. Niemeyer
Keyword(s):  
Disease Recurrence ◽  
Mitogen Activated Protein Kinase ◽  
Leukemic Cells ◽  
Juvenile Myelomonocytic Leukemia ◽  
Hematopoietic Stem ◽  
Ras Mutations ◽  
Mitogen Activated Protein ◽  
Myelomonocytic Leukemia ◽  
Kinase Pathway ◽  
Excessive Proliferation

Abstract Juvenile myelomonocytic leukemia (JMML) is a unique, aggressive hematopoietic disorder of infancy/early childhood caused by excessive proliferation of cells of monocytic and granulocytic lineages. Approximately 90% of patients carry either somatic or germline mutations of PTPN-11, K-RAS, N-RAS, CBL, or NF1 in their leukemic cells. These genetic aberrations are largely mutually exclusive and activate the Ras/mitogen-activated protein kinase pathway. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the therapy of choice for most patients with JMML, curing more than 50% of affected children. We recommend that this option be promptly offered to any child with PTPN-11-, K-RAS-, or NF1-mutated JMML and to the majority of those with N-RAS mutations. Because children with CBL mutations and few of those with N-RAS mutations may have spontaneous resolution of hematologic abnormalities, the decision to proceed to transplantation in these patients must be weighed carefully. Disease recurrence remains the main cause of treatment failure after HSCT. A second allograft is recommended if overt JMML relapse occurs after transplantation. Recently, azacytidine, a hypomethylating agent, was reported to induce hematologic/molecular remissions in some children with JMML, and its role in both reducing leukemia burden before HSCT and in nontransplant settings requires further studies.

scholarly journals Subclonal mutations in SETBP1 confer a poor prognosis in juvenile myelomonocytic leukemia

Blood ◽  
2015 ◽  
Vol 125 (3) ◽  
pp. 516-524 ◽  
Author(s):  
Elliot Stieglitz ◽  
Camille B. Troup ◽  
Laura C. Gelston ◽  
John Haliburton ◽  
Eric D. Chow ◽  
...  
Keyword(s):  
Hematopoietic Stem Cell Transplant ◽  
Juvenile Myelomonocytic Leukemia ◽  
Cell Transplant ◽  
Hematopoietic Stem ◽  
Dismal Prognosis ◽  
Key Points ◽  
Polymerase Chain ◽  
Rare Cells ◽  
Digital Polymerase Chain Reaction ◽  
Myelomonocytic Leukemia

Key Points Mutations in SETBP1 can be detected using droplet digital polymerase chain reaction in at least 30% of patients with JMML and are associated with a dismal prognosis. Patients harboring rare cells with mutant SETBP1 at diagnosis should be considered candidates for swift hematopoietic stem cell transplant.

scholarly journals Therapeutic targeting of FLT3 and associated drug resistance in acute myeloid leukemia

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Melat T. Gebru ◽  
Hong-Gang Wang
Keyword(s):  
Drug Resistance ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Gene Mutations ◽  
Standard Of Care ◽  
Cell Transplant ◽  
Current Standard ◽  
Hematopoietic Stem ◽  
Acute Myeloid

AbstractAcute myeloid leukemia (AML) is a heterogeneous disease caused by several gene mutations and cytogenetic abnormalities affecting differentiation and proliferation of myeloid lineage cells. FLT3 is a receptor tyrosine kinase commonly overexpressed or mutated, and its mutations are associated with poor prognosis in AML. Although aggressive chemotherapy often followed by hematopoietic stem cell transplant is the current standard of care, the recent approval of FLT3-targeted drugs is revolutionizing AML treatment that had remained unchanged since the 1970s. However, despite the dramatic clinical response to targeted agents, such as FLT3 inhibitors, remission is almost invariably short-lived and ensued by relapse and drug resistance. Hence, there is an urgent need to understand the molecular mechanisms driving drug resistance in order to prevent relapse. In this review, we discuss FLT3 as a target and highlight current understanding of FLT3 inhibitor resistance.

scholarly journals Pediatric myelodysplastic syndrome

2018 ◽  
Vol 5 (3) ◽  
pp. 23-35
Author(s):  
B. V. Afanasyev ◽  
L. Zubarovskaya
Keyword(s):  
Bone Marrow ◽  
Myelodysplastic Syndrome ◽  
Germ Line ◽  
Bone Marrow Failure ◽  
Juvenile Myelomonocytic Leukemia ◽  
Hematopoietic Stem ◽  
Main Method ◽  
Bone Marrow Failure Syndromes ◽  
Or Gene ◽  
Myelomonocytic Leukemia

Pediatric myelodysplastic syndrome (MDS) are a heterogeneous group of clonal disorders often occur in the context of inherited bone marrow failure syndromes, acquired aplastic anemia or gene predisposition. Germ line syndromes predisposing individuals to develop familial MDS or acute myeloid leukemia have recently been identified – mutations in RUNX1, ANKRD, GATA2, ETV6, SRP72, DDX41. Juvenile myelomonocytic leukemia (JMML) occurs in context of inherited and somatic mutations PTPN11, KRAS, NRAS, CBL, NF1. In pathogenesis of these disorders there are a several factors – hypermethylation, clonal hematopoiesis/cytopenia of undetermined significance, disturbances of bone marrow microenvironment, telomeres, immune mechanisms. Allogeneic hematopoietic stem cell transplantation is the main method of MDS and JMML treatment but it is necessary to take into account special indications for refractory cytopenia (infections, dependence on blood transfusions) and be careful for JMML with CBL mutation.

scholarly journals Immunophenotypic and Genetic Overlap between JMML and CMML

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1803-1803
Author(s):  
Cody E. Cotner ◽  
Mitul Modi ◽  
Gerald Wertheim ◽  
Michele Paessler ◽  
Sarah K. Tasian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Histone Modification ◽  
Research Funding ◽  
Juvenile Myelomonocytic Leukemia ◽  
Cell Transplant ◽  
Sequencing Analysis ◽  
Hematopoietic Stem ◽  
Bone Marrow Biopsies ◽  
Ras Pathway ◽  
Myelomonocytic Leukemia

Abstract Introduction: Juvenile myelomonocytic leukemia (JMML) is a rare hematological malignancy of early childhood with characteristics of both myeloproliferative neoplasms and myelodysplastic syndromes. JMML shares pathological features and diagnostic criteria with chronic myelomonocytic leukemia (CMML), a malignancy predominantly affecting the elderly. While 85% of patients with JMML have somatic or germline mutations in RAS pathway genes (NF1, NRAS, KRAS, PTPN11, and CBL), the most frequently mutated genes in CMML include TET2, SRSF2, ASXL1, and RAS and are generally somatic-only. The extent to which histone modification genes (ASXL1, EZH2) or spliceosome machinery genes (SF3B1, SRSF2, U2AF1, ZRSR2) play a role in JMML pathogenesis is unclear. Despite mutational differences, both JMML and CMML manifest as myelomonocytic proliferation with varying amounts of dysplasia in the bone marrow. Clusters of clonally-related CD123+ plasmacytoid dendritic cells (PDCs) have been observed in the bone marrow of patients with CMML but have not been investigated in JMML. Here, we report the mutation profiles and immunophenotypic characteristics of JMML specimens from children treated at our institution. Methods: The pathology archives (1987-2017) at the Children's Hospital of Philadelphia (CHOP) were searched to identify JMML cases (n=21) and included formalin fixed paraffin-embedded diagnostic bone marrow biopsies and splenectomy tissue obtained prior to hematopoietic stem cell transplant. JMML diagnosis was confirmed in all cases by clinicopathological review. Cytogenetic analysis and whole genome SNP array were performed at initial clinical presentation. Genomic DNA and RNA were extracted from JMML patients' bone marrow (n=8) and spleen tissue (n=10) for next-generation sequencing analysis of 118 cancer genes for sequence and copy number variants and 110 genes for known and novel fusions via our custom CHOP Hematologic Cancer Panel. CD123 immunohistochemical (IHC) staining was performed on bone marrow and spleen tissues from children with JMML. Presence of CD123+ PDC clusters was evaluated manually and by digital image analysis. CD123 staining was enumerated using the Aperio Image Scope quantitation of membranous staining v9 with the analysis parameters set such that normal endothelial staining was quantified as 1+, and true CD123 staining cells were quantified as 2+ or 3+. The percentage of CD123+ cells (out of total cellularity) was calculated. Bone marrow from patients with non-JMML myeloid malignancies (n=6) and splenectomy tissue from patients with sickle cell anemia (n=8) were used as controls for the CD123 IHC analysis. Results: We confirmed canonical JMML-associated somatic or germline NF1 (n=3), NRAS (n=4), KRAS (n=2), PTPN11 (n=6), or CBL (n=2) mutations in 16 of the 17 (94%) patients with sequencing data. Interestingly, both PTPN11A72T and NF1R2637* mutations were detected in one patient. In addition, we found potential variants in genes affecting histone modifications (ASXL1, DNMT3A, KDM6A, SETD2), spliceosomal processes (SF3B1, U2AF1), transcription (BCOR, RUNX1, ETV6), or cellular growth (SETBP1, BRAF) in 8/17 patients (47%). While mutations in these genes have been well-characterized in other myeloid disorders, many of these alterations have not been reported to date in children with JMML or are currently of unclear biologic and prognostic significance. We also observed increased clustering of CD123+ PDCs in bone marrow and spleens from patients with JMML compared to IHC staining of control tissues. 2.2 ± 0.42% and 1.8 ± 0.74% of cells expressed CD123 in the spleen and bone marrow specimens, respectively. Control bone marrow and spleen samples did not show significant CD123+ staining. Conclusions: Our study demonstrates frequent variants in histone modification, splicing, and transcription-associated genes in JMML specimens in addition to known pathogenic RAS pathway mutations. We further report histopathologic CD123+ PDC clustering in JMML specimens analogous to that observed in CMML, which may aid in the workup of this often difficult-to-diagnose disease. Our findings of genetic and immunophenotypic overlap between JMML and CMML suggest similarities in pathogenesis despite typical presentation at extremes of age. Disclosures Tasian: Aleta Biopharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Research Funding; Incyte Corporation: Research Funding.

scholarly journals Bedside to bench in juvenile myelomonocytic leukemia: insights into leukemogenesis from a rare pediatric leukemia

Blood ◽  
2014 ◽  
Vol 124 (16) ◽  
pp. 2487-2497 ◽  
Author(s):  
Tiffany Y. Chang ◽  
Christopher C. Dvorak ◽  
Mignon L. Loh
Keyword(s):  
Myeloproliferative Neoplasm ◽  
World Health ◽  
Driver Mutations ◽  
Juvenile Myelomonocytic Leukemia ◽  
Ras Signaling ◽  
Cell Transplant ◽  
Pediatric Leukemia ◽  
Hematopoietic Stem ◽  
Molecular Features ◽  
Myelomonocytic Leukemia

AbstractJuvenile myelomonocytic leukemia (JMML) is a typically aggressive myeloid neoplasm of childhood that is clinically characterized by overproduction of monocytic cells that can infiltrate organs, including the spleen, liver, gastrointestinal tract, and lung. JMML is categorized as an overlap myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) by the World Health Organization and also shares some clinical and molecular features with chronic myelomonocytic leukemia, a similar disease in adults. Although the current standard of care for patients with JMML relies on allogeneic hematopoietic stem cell transplant, relapse is the most frequent cause of treatment failure. Tremendous progress has been made in defining the genomic landscape of JMML. Insights from cancer predisposition syndromes have led to the discovery of nearly 90% of driver mutations in JMML, all of which thus far converge on the Ras signaling pathway. This has improved our ability to accurately diagnose patients, develop molecular markers to measure disease burden, and choose therapeutic agents to test in clinical trials. This review emphasizes recent advances in the field, including mapping of the genomic and epigenome landscape, insights from new and existing disease models, targeted therapeutics, and future directions.

scholarly journals Juvenile Myelomonocytic Leukemia and other myelodysplastic/myeloproliferative neoplasms

JBMTCT ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 128
Author(s):  
Neysimelia Costa Villela ◽  
Roseane Vasconcelos Gouveia ◽  
Simone De Castro Resende Franco ◽  
Gustavo Zamperlini ◽  
Patrícia Shimoda Ikeuti ◽  
...  
Keyword(s):  
Stem Cell ◽  
Clinical Course ◽  
Myeloproliferative Neoplasms ◽  
Spontaneous Resolution ◽  
Juvenile Myelomonocytic Leukemia ◽  
Ras Signaling ◽  
Hematopoietic Stem ◽  
Ras Signaling Pathway ◽  
Myelomonocytic Leukemia ◽  
Over Time

Juvenile Myelomonocytic Leukemia (JMML) is a clonal hematopoietic disorder that usually occurs in early childhood, characterized by hyperactivation of the RAS signaling pathway. About 90% of patients have mutations in 1 of 5 genes (PTPN11, NRAS, KRAS, NF1, CBL) that define genetically and clinically distinct subtypes of the disease, with a highly variable clinical course. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the therapy of choice for most patients with JMML, although children with CBL mutations and few of those with N-RAS mutations may have spontaneous resolution of hematologic abnormalities. The results of HSCT in patients with JMML have progressively improved over time, but relapse is still an important cause of treatment failure.

scholarly journals Autoimmune Complications in Hematologic Neoplasms

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1532
Author(s):  
Wilma Barcellini ◽  
Juri Alessandro Giannotta ◽  
Bruno Fattizzo
Keyword(s):  
Lupus Erythematosus ◽  
Checkpoint Inhibitors ◽  
Myeloproliferative Neoplasms ◽  
Pure Red Cell Aplasia ◽  
Lymphocytic Leukemia ◽  
Cell Transplant ◽  
Acute Leukemias ◽  
Hematopoietic Stem ◽  
Non Hodgkin Lymphoma ◽  
Diagnostic Difficulties

Autoimmune cytopenias (AICy) and autoimmune diseases (AID) can complicate both lymphoid and myeloid neoplasms, and often represent a diagnostic and therapeutic challenge. While autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) are well known, other rarer AICy (autoimmune neutropenia, aplastic anemia, and pure red cell aplasia) and AID (systemic lupus erythematosus, rheumatoid arthritis, vasculitis, thyroiditis, and others) are poorly recognized. This review analyses the available literature of the last 30 years regarding the occurrence of AICy/AID in different onco-hematologic conditions. The latter include chronic lymphocytic leukemia (CLL), lymphomas, multiple myeloma, myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML), myeloproliferative neoplasms, and acute leukemias. On the whole, AICy are observed in up to 10% of CLL and with higher frequencies in certain subtypes of non-Hodgkin lymphoma, whilst they occur in less than 1% of low-risk MDS and CMML. AID are described in up to 30% of myeloid and lymphoid patients, including immune-mediated hemostatic disorders (acquired hemophilia, thrombotic thrombocytopenic purpura, and anti-phospholipid syndrome) that may be severe and fatal. Additionally, AICy/AID are found in about 10% of patients receiving hematopoietic stem cell transplant or treatment with new checkpoint inhibitors. Besides the diagnostic difficulties, these AICy/AID may complicate the clinical management of already immunocompromised patients.

scholarly journals Stat5 activation enables erythropoiesis in the absence of EpoR and Jak2

Blood ◽  
2008 ◽  
Vol 111 (9) ◽  
pp. 4511-4522 ◽  
Author(s):  
Florian Grebien ◽  
Marc A. Kerenyi ◽  
Boris Kovacic ◽  
Thomas Kolbe ◽  
Verena Becker ◽  
...  
Keyword(s):  
Fetal Liver ◽  
Janus Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Independent Manner ◽  
Hematopoietic Stem ◽  
Tyrosine Kinase Signaling ◽  
Fusion Construct ◽  
Downstream Effector ◽  
Kit Receptor ◽  
Mitogen Activated Protein

Abstract Erythropoiesis requires erythropoietin (Epo) and stem cell factor (SCF) signaling via their receptors EpoR and c-Kit. EpoR, like many other receptors involved in hematopoiesis, acts via the kinase Jak2. Deletion of EpoR or Janus kinase 2 (Jak2) causes embryonic lethality as a result of defective erythropoiesis. The contribution of distinct EpoR/Jak2-induced signaling pathways (mitogen-activated protein kinase, phosphatidylinositol 3-kinase, signal transducer and activator of transcription 5 [Stat5]) to functional erythropoiesis is incompletely understood. Here we demonstrate that expression of a constitutively activated Stat5a mutant (cS5) was sufficient to relieve the proliferation defect of Jak2−/− and EpoR−/− cells in an Epo-independent manner. In addition, tamoxifen-induced DNA binding of a Stat5a–estrogen receptor (ER)* fusion construct enabled erythropoiesis in the absence of Epo. Furthermore, c-Kit was able to enhance signaling through the Jak2-Stat5 axis, particularly in lymphoid and myeloid progenitors. Although abundance of hematopoietic stem cells was 2.5-fold reduced in Jak2−/− fetal livers, transplantation of Jak2−/−-cS5 fetal liver cells into irradiated mice gave rise to mature erythroid and myeloid cells of donor origin up to 6 months after transplantation. Cytokine- and c-Kit pathways do not function independently of each other in hematopoiesis but cooperate to attain full Jak2/Stat5 activation. In conclusion, activated Stat5 is a critical downstream effector of Jak2 in erythropoiesis/myelopoiesis, and Jak2 functionally links cytokine- with c-Kit-receptor tyrosine kinase signaling.

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