1 960 168 CHRONIC MYELOMONOCYTIC LEUKEMIA: 2016 UPDATE ON DIAGNOSIS, RISK STRATIFICATION, AND MANAGEMENT. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL HEMATOPOIETIC STEM CELL DISORDER CHARACTERIZED BY OVERLAPPING FEATURES OF MYELODYSPLASTIC SYNDROMES AND MYELOPROLIFERATIVE NEOPLASMS. DIAGNOSIS IS BASED ON THE PRESENCE OF PERSISTENT (>3 MONTHS) PERIPHERAL BLOOD MONOCYTOSIS (>1 X 10(9) /L), ALONG WITH BONE MARROW DYSPLASIA. CLONAL CYTOGENETIC ABNORMALITIES OCCUR IN APPROXIMATELY 20-30% OF PATIENTS, WHILE >90% HAVE GENE MUTATIONS. MUTATIONS INVOLVING TET2 ( APPROXIMATELY 60%), SRSF2 ( APPROXIMATELY 50%), ASXL1 ( APPROXIMATELY 40%), AND RAS ( APPROXIMATELY 30%) ARE FREQUENT; WITH ONLY ASXL1 MUTATIONS NEGATIVELY IMPACTING OVERALL SURVIVAL. TWO MOLECULARLY INTEGRATED, CMML-SPECIFIC PROGNOSTIC MODELS INCLUDE; THE GROUPE FRANCAIS DES MYELODYSPLASIES (GFM) AND THE MOLECULAR MAYO MODEL (MMM). THE GFM MODEL SEGREGATES PATIENTS INTO 3 GROUPS BASED ON: AGE >65 YEARS, WBC >15 X 10(9) /L, ANEMIA, PLATELETS <100 X 10(9) /L, AND ASXL1 MUTATION STATUS, WITH RESPECTIVE MEDIAN SURVIVALS OF 56 (LOW), 27.4 (INTERMEDIATE), AND 9.2 (HIGH) MONTHS. THE MMM IS BASED ON ASXL1 MUTATIONAL STATUS, ABSOLUTE MONOCYTE COUNT >10 X 10(9) /L, HEMOGLOBIN <10 G/DL, PLATELETS <100 X 109/L AND CIRCULATING IMMATURE MYELOID CELLS. THIS MODEL STRATIFIES PATIENTS INTO FOUR GROUPS; HIGH (>/=3 RISK FACTORS), INTERMEDIATE-2 (2 RISK FACTORS), INTERMEDIATE-1 (1 RISK FACTOR) AND LOW (NO RISK FACTORS), WITH MEDIAN SURVIVALS OF 16, 31, 59, AND 97 MONTHS, RESPECTIVELY. HYPOMETHYLATING AGENTS SUCH AS 5-AZACITIDINE AND DECITABINE ARE COMMONLY USED, WITH OVERALL RESPONSE RATES OF APPROXIMATELY 30-40% AND COMPLETE REMISSION RATES OF APPROXIMATELY 7-17%. ALLOGENEIC STEM CELL TRANSPLANT IS THE ONLY POTENTIALLY CURATIVE OPTION, BUT IS ASSOCIATED WITH SIGNIFICANT MORBIDITY AND MORTALITY. INDIVIDUALIZED THERAPY, INCLUDING EPIGENETIC MODIFIERS AND SMALL MOLECULE INHIBITORS, ARE EXCITING PROSPECTS. AM. J. HEMATOL. 91:632-642, 2016. (C) 2016 WILEY PERIODICALS, INC. 2016 2 961 76 CHRONIC MYELOMONOCYTIC LEUKEMIA: A GENETIC AND CLINICAL UPDATE. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL STEM CELL DISORDER, CHARACTERIZED BY PERIPHERAL BLOOD MONOCYTOSIS AND OVERLAPPING FEATURES BETWEEN MYELODYSPLASTIC SYNDROMES (MDS) AND MYELOPROLIFERATIVE NEOPLASMS (MPNS). CLONAL CYTOGENETIC CHANGES ARE SEEN IN UP TO 30 % PATIENTS, WHILE APPROXIMATELY 90 % HAVE DETECTABLE MOLECULAR ABNORMALITIES. MOST PATIENTS ARE DIAGNOSED IN THE SEVENTH DECADE OF LIFE. GENE MUTATIONS IN TEN-ELEVEN TRANSLOCATION (TET) ONCOGENE FAMILY MEMBER 2 (TET2) (60 %), SRSF2 (50 %), ASXL1 (40 %), AND RAS (20-30 %) ARE FREQUENT, WITH ONLY FRAME SHIFT AND NONSENSE ASXL1 MUTATIONS NEGATIVELY IMPACTING OVERALL SURVIVAL. WITH THE LACK OF FORMAL GUIDELINES, MANAGEMENT AND RESPONSE CRITERIA ARE OFTEN EXTRAPOLATED FROM MDS AND MPN. CONTEMPORARY MOLECULARLY INTEGRATED CMML-SPECIFIC PROGNOSTIC MODELS INCLUDE THE GROUPE FRANCAIS DES MYELODYSPLASIES (GFM) MODEL AND THE MOLECULAR MAYO MODEL, BOTH INCORPORATING ASXL1 MUTATIONAL STATUS. HYPOMETHYLATING AGENTS AND ALLOGENEIC STEM CELL TRANSPLANT REMAIN THE TWO MOST COMMONLY USED TREATMENT STRATEGIES, WITH SUBOPTIMAL RESULTS. CLINICAL TRIALS EXPLOITING EPIGENETIC AND SIGNAL PATHWAY ABNORMALITIES, FREQUENT IN CMML, OFFER HOPE AND PROMISE. 2015 3 962 75 CHRONIC MYELOMONOCYTIC LEUKEMIA: FOCUS ON CLINICAL PRACTICE. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL STEM CELL DISORDER WITH FEATURES THAT OVERLAP THOSE OF MYELODYSPLASTIC SYNDROMES (MDSS) AND MYELOPROLIFERATIVE NEOPLASMS (MPNS). CHRONIC MYELOMONOCYTIC LEUKEMIA OFTEN RESULTS IN PERIPHERAL BLOOD MONOCYTOSIS AND HAS AN INHERENT TENDENCY TO TRANSFORM TO ACUTE MYELOID LEUKEMIA. CLONAL CYTOGENETIC CHANGES ARE SEEN IN APPROXIMATELY 30% OF PATIENTS, AND MOLECULAR ABNORMALITIES ARE SEEN IN MORE THAN 90%. GENE MUTATIONS INVOLVING TET2 ( APPROXIMATELY 60%), SRSF2 ( APPROXIMATELY 50%), ASXL1 ( APPROXIMATELY 40%), AND RAS ( APPROXIMATELY 30%) ARE FREQUENT, WITH NONSENSE AND FRAMESHIFT ASXL1 MUTATIONS BEING THE ONLY MUTATIONS IDENTIFIED THUS FAR TO HAVE AN INDEPENDENT NEGATIVE PROGNOSTIC EFFECT ON OVERALL SURVIVAL. CONTEMPORARY MOLECULARLY INTEGRATED PROGNOSTIC MODELS (INCLUSIVE OF ASXL1 MUTATIONS) INCLUDE THE MOLECULAR MAYO MODEL AND THE GROUPE FRANCAIS DES MYELODYSPLASIES MODEL. GIVEN THE LACK OF FORMAL TREATMENT AND RESPONSE CRITERIA, MANAGEMENT OF CMML IS OFTEN EXTRAPOLATED FROM MDS AND MPN, WITH ALLOGENEIC STEM CELL TRANSPLANT BEING THE ONLY CURATIVE OPTION. HYDROXYUREA AND OTHER CYTOREDUCTIVE AGENTS HAVE BEEN USED TO CONTROL MPN-LIKE FEATURES, WHILE EPIGENETIC MODIFIERS SUCH AS HYPOMETHYLATING AGENTS HAVE BEEN USED FOR MDS-LIKE FEATURES. GIVEN THE RELATIVELY POOR RESPONSE TO THESE AGENTS AND THE INHERENT RISKS ASSOCIATED WITH HEMATOPOIETIC STEM CELL TRANSPLANT, NEWER DRUGS EXPLOITING MOLECULAR AND EPIGENETIC ABNORMALITIES IN CMML ARE BEING DEVELOPED. THE CREATION OF CMML-SPECIFIC RESPONSE CRITERIA IS A MUCH NEEDED STEP IN ORDER TO IMPROVE CLINICAL OUTCOMES. 2016 4 1266 67 CYTOGENETIC AND MOLECULAR ABNORMALITIES IN CHRONIC MYELOMONOCYTIC LEUKEMIA. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A CLONAL STEM CELL DISORDER ASSOCIATED WITH PERIPHERAL BLOOD MONOCYTOSIS AND AN INHERENT TENDENCY TO TRANSFORM TO ACUTE MYELOID LEUKEMIA. CMML HAS OVERLAPPING FEATURES OF MYELODYSPLASTIC SYNDROMES AND MYELOPROLIFERATIVE NEOPLASMS. CLONAL CYTOGENETIC CHANGES ARE SEEN IN ~30%, WHEREAS GENE MUTATIONS ARE SEEN IN >90% OF PATIENTS. COMMON CYTOGENETIC ABNORMALITIES INCLUDE; TRISOMY 8, -Y, -7/DEL(7Q), TRISOMY 21 AND DEL(20Q), WITH THE MAYO-FRENCH RISK STRATIFICATION EFFECTIVELY RISK STRATIFYING PATIENTS BASED ON CYTOGENETIC ABNORMALITIES. GENE MUTATIONS FREQUENTLY INVOLVE EPIGENETIC REGULATORS (TET2 ~60%), MODULATORS OF CHROMATIN (ASXL1 ~40%), SPLICEOSOME COMPONENTS (SRSF2 ~50%), TRANSCRIPTION FACTORS (RUNX1 ~15%) AND SIGNAL PATHWAYS (RAS ~30%, CBL ~15%). OF THESE, THUS FAR, ONLY NONSENSE AND FRAMESHIFT ASXL1 MUTATIONS HAVE BEEN SHOWN TO NEGATIVELY IMPACT OVERALL SURVIVAL. THIS HAS RESULTED IN THE DEVELOPMENT OF CONTEMPORARY, MOLECULARLY INTEGRATED (INCLUSIVE OF ASXL1 MUTATIONS) CMML PROGNOSTIC MODELS, INCLUDING MOLECULAR MAYO MODEL AND THE GROUPE FRANCAIS DES MYELODYSPLASIES MODEL. BETTER UNDERSTANDING OF THE PREVALENT GENETIC AND EPIGENETIC DYSREGULATION HAS RESULTED IN EMERGING TARGETED TREATMENT OPTIONS FOR SOME PATIENTS. THE DEVELOPMENT OF AN INTEGRATED (CYTOGENETIC AND MOLECULAR) PROGNOSTIC MODEL ALONG WITH CMML-SPECIFIC RESPONSE ASSESSMENT CRITERIA ARE MUCH NEEDED FUTURE GOALS. 2016 5 4562 76 MYELODYSPLASTIC SYNDROME/MYELOPROLIFERATIVE NEOPLASM OVERLAP SYNDROMES: A FOCUSED REVIEW. MYELODYSPLASTIC SYNDROME (MDS)/MYELOPROLIFERATIVE NEOPLASM (MPN) OVERLAP SYNDROMES ARE UNIQUE MYELOID NEOPLASMS, WITH OVERLAPPING FEATURES OF MDS AND MPN. THEY CONSIST OF FOUR ADULT ONSET ENTITIES INCLUDING CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), MDS/MPN-RING SIDEROBLASTS-THROMBOCYTOSIS (MDS/MPN-RS-T), BCR-ABL1 NEGATIVE ATYPICAL CHRONIC MYELOID LEUKEMIA (ACML) AND MDS/MPN-UNCLASSIFIABLE (MDS/MPN-U); WITH JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) BEING THE ONLY PEDIATRIC ONSET ENTITY. AMONG THESE OVERLAP NEOPLASMS, CMML IS THE MOST FREQUENT AND IS HALLMARKED BY THE PRESENCE OF SUSTAINED PERIPHERAL BLOOD MONOCYTOSIS WITH RECURRENT MUTATIONS INVOLVING TET2 (60%), SRSF2 (50%) AND ASXL1 (40%); WITH RAS PATHWAY MUTATIONS AND JAK2V617F BEING RELATIVELY ENRICHED IN PROLIFERATIVE CMML SUBTYPES (WBC >/=13 X 109/L). CMML USUALLY PRESENTS IN THE 7TH DECADE OF LIFE, WITH A MALE PREPONDERANCE AND IS ASSOCIATED WITH A MEDIAN OVERALL SURVIVAL OF <36 MONTHS. ADVERSE PROGNOSTICATORS IN CMML INCLUDE INCREASING AGE, HIGH WBC, PRESENCE OF CIRCULATING IMMATURE MYELOID CELLS, ANEMIA, THROMBOCYTOPENIA AND TRUNCATING ASXL1 MUTATIONS. WHILE ALLOGENEIC STEM CELL TRANSPLANTATION REMAINS THE ONLY CURATIVE OPTION, GIVEN THE LATE ONSET OF THIS NEOPLASM AND HIGH FREQUENCY OF COMORBIDITIES, MOST PATIENTS REMAIN INELIGIBLE. HYPOMETHYLATING AGENTS SUCH AS AZACITIDINE, DECITABINE AND ORAL DECITABINE/CEDAZURIDINE HAVE BEEN US FDA APPROVED FOR THE MANAGEMENT OF CMML, WITH OVERALL RESPONSE RATES OF 40-50% AND COMPLETE REMISSION RATES OF <20%. WHILE THESE AGENTS EPIGENETICALLY RESTORE HEMATOPOIESIS IN A SUBSET OF RESPONDING PATIENTS, THEY DO NOT IMPACT MUTATIONAL ALLELE BURDENS AND EVENTUAL DISEASE PROGRESSION TO AML REMAINS INEVITABLE. NEWER TREATMENT MODALITIES EXPLOITING EPIGENETIC, SIGNALING AND SPLICING ABNORMALITIES COMMONLY SEEN IN CMML ARE MUCH NEEDED. 2020 6 4555 33 MUTATIONAL SPECTRUM ANALYSIS OF CHRONIC MYELOMONOCYTIC LEUKEMIA INCLUDES GENES ASSOCIATED WITH EPIGENETIC REGULATION: UTX, EZH2, AND DNMT3A. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), A MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASM, IS CHARACTERIZED BY MONOCYTIC PROLIFERATION, DYSPLASIA, AND PROGRESSION TO ACUTE MYELOID LEUKEMIA. CMML HAS BEEN ASSOCIATED WITH SOMATIC MUTATIONS IN DIVERSE RECENTLY IDENTIFIED GENES. WE ANALYZED 72 WELL-CHARACTERIZED PATIENTS WITH CMML (N = 52) AND CMML-DERIVED ACUTE MYELOID LEUKEMIA (N = 20) FOR RECURRENT CHROMOSOMAL ABNORMALITIES WITH THE USE OF ROUTINE CYTOGENETICS AND SINGLE NUCLEOTIDE POLYMORPHISM ARRAYS ALONG WITH COMPREHENSIVE MUTATIONAL SCREENING. CYTOGENETIC ABERRATIONS WERE PRESENT IN 46% OF CASES, WHEREAS SINGLE NUCLEOTIDE POLYMORPHISM ARRAY INCREASED THE DIAGNOSTIC YIELD TO 60%. AT LEAST 1 MUTATION WAS FOUND IN 86% OF ALL CASES; NOVEL UTX, DNMT3A, AND EZH2 MUTATIONS WERE FOUND IN 8%, 10%, AND 5.5% OF PATIENTS, RESPECTIVELY. TET2 MUTATIONS WERE PRESENT IN 49%, ASXL1 IN 43%, CBL IN 14%, IDH1/2 IN 4%, KRAS IN 7%, NRAS IN 4%, AND JAK2 V617F IN 1% OF PATIENTS. VARIOUS MUTANT GENOTYPE COMBINATIONS WERE OBSERVED, INDICATING MOLECULAR HETEROGENEITY IN CMML. OUR RESULTS SUGGEST THAT MOLECULAR DEFECTS AFFECTING DISTINCT PATHWAYS CAN LEAD TO SIMILAR CLINICAL PHENOTYPES. 2011 7 4557 25 MUTATIONS IN ASXL1 ARE ASSOCIATED WITH POOR PROGNOSIS ACROSS THE SPECTRUM OF MALIGNANT MYELOID DISEASES. THE ASXL1 GENE IS ONE OF THE MOST FREQUENTLY MUTATED GENES IN MALIGNANT MYELOID DISEASES. THE ASXL1 PROTEIN BELONGS TO PROTEIN COMPLEXES INVOLVED IN THE EPIGENETIC REGULATION OF GENE EXPRESSION. ASXL1 MUTATIONS ARE FOUND IN MYELOPROLIFERATIVE NEOPLASMS (MPN), MYELODYSPLASTIC SYNDROMES (MDS), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AND ACUTE MYELOID LEUKEMIA (AML). THEY ARE GENERALLY ASSOCIATED WITH SIGNS OF AGGRESSIVENESS AND POOR CLINICAL OUTCOME. BECAUSE OF THIS, A SYSTEMATIC DETERMINATION OF ASXL1 MUTATIONAL STATUS IN MYELOID MALIGNANCIES SHOULD HELP IN PROGNOSIS ASSESSMENT. 2012 8 3560 38 IMPACT OF CLINICAL, CYTOGENETIC, AND MOLECULAR PROFILES ON LONG-TERM SURVIVAL AFTER TRANSPLANTATION IN PATIENTS WITH CHRONIC MYELOMONOCYTIC LEUKEMIA. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) IS A HETEROGENEOUS GROUP OF CLONAL HEMATOPOIETIC MALIGNANCIES WITH VARIABLE CLINICAL AND MOLECULAR FEATURES. WE ANALYZED LONG-TERM RESULTS OF ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION IN PATIENTS WITH CMML AND DETERMINED CLINICAL AND MOLECULAR RISK FACTORS ASSOCIATED WITH OUTCOMES. DATA FROM 129 PATIENTS, AGED 7-74 (MEDIAN 55) YEARS, AT VARIOUS STAGES OF THE DISEASE AND TRANSPLANTED FROM RELATED OR UNRELATED DONORS WERE ANALYZED. USING A PANEL OF 75 GENES SOMATIC MUTATIONS PRESENT BEFORE HEMATOPOIETIC CELL TRANSPLANTATION WERE IDENTIFIED IN 52 PATIENTS. THE PROGRESSION-FREE SURVIVAL RATE AT 10 YEARS WAS 29%. THE MAJOR CAUSE OF DEATH WAS RELAPSE (32%), WHICH WAS SIGNIFICANTLY ASSOCIATED WITH ADVERSE CYTOGENETICS (HAZARD RATIO, 3.77; P=0.0002), CMML PROGNOSTIC SCORING SYSTEM (HAZARD RATIO, 14.3, P=0.01), AND MD ANDERSON PROGNOSTIC SCORES (HAZARD RATIO, 9.4; P=0.005). MORTALITY WAS ASSOCIATED WITH HIGH-RISK CYTOGENETICS (HAZARD RATIO, 1.88; P=0.01) AND HIGH HEMATOPOIETIC CELL TRANSPLANTATION COMORBIDITY INDEX (SCORE >/=4: HAZARD RATIO, 1.99; P=0.01). HIGH OVERALL MUTATION BURDEN (>/=10 MUTATIONS: HAZARD RATIO, 3.4; P=0.02), AND >/=4 MUTATED EPIGENETIC REGULATORY GENES (HAZARD RATIO 5.4; P=0.003) WERE LINKED TO RELAPSE. UNSUPERVISED CLUSTERING OF THE CORRELATION MATRIX REVEALED DISTINCT HIGH-RISK GROUPS WITH UNIQUE ASSOCIATIONS OF MUTATIONS AND CLINICAL FEATURES. CMML WITH A HIGH MUTATION BURDEN APPEARED TO BE DISTINCT FROM HIGH-RISK GROUPS DEFINED BY COMPLEX CYTOGENETICS. NEW TRANSPLANT STRATEGIES MUST BE DEVELOPED TO TARGET SPECIFIC DISEASE SUBGROUPS, STRATIFIED BY MOLECULAR PROFILING AND CLINICAL RISK FACTORS. 2020 9 957 45 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. 2014 10 959 41 CHRONIC MYELOMONOCYTIC LEUKEMIA AND ATYPICAL CHRONIC MYELOID LEUKEMIA: NOVEL PATHOGENETIC LESIONS. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AND ATYPICAL CHRONIC MYELOID LEUKEMIA (ACML) ARE DISTINCT, YET RELATED, ENTITIES OF MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASMS (MDS/MPN) CHARACTERIZED BY MORPHOLOGIC DYSPLASIA WITH ACCUMULATION OF MONOCYTES OR NEUTROPHILS, RESPECTIVELY. OUR UNDERSTANDING OF THE MOLECULAR PATHOGENESIS OF CMML AND ACML HAS ADVANCED, MAINLY DUE TO THE APPLICATION OF NOVEL TECHNOLOGIES SUCH AS ARRAY-BASED KARYOTYPING AND NEXT-GENERATION SEQUENCING. IN ADDITION TO PREVIOUSLY KNOWN RECURRENT ABERRATIONS, SOMATIC UNIPARENTAL DISOMY AFFECTING CHROMOSOMES 3, 4, 7, AND 11 FREQUENTLY OCCURS IN CMML. NOVEL SOMATIC MUTATIONS OF GENES, INCLUDING THOSE ASSOCIATED WITH PROLIFERATION SIGNALING (CBL, RAS, RUNX1, JAK2 (V617F)) AND WITH MODIFICATION OF EPIGENETIC STATUS (TET2, ASXL1, UTX, EZH2) HAVE BEEN FOUND. VARIOUS COMBINATIONS OF MUTATIONS SUGGEST A MULTISTEP PATHOGENESIS AND MAY ACCOUNT FOR CLINICAL HETEROGENEITY. MOST RECENTLY, SEVERAL SPLICEOSOME-ASSOCIATED-GENE MUTATIONS WERE REPORTED AND SRSF2 MUTATIONS ARE FREQUENTLY DETECTED IN CMML. THE PROGNOSTIC AND DIAGNOSTIC SIGNIFICANCE OF THESE MOLECULAR LESIONS, IN PARTICULAR THEIR VALUE AS BIOMARKERS OF RESPONSE OR RESISTANCE TO SPECIFIC THERAPIES, WHILE UNCERTAIN NOW IS LIKELY TO BE CLARIFIED AS LARGE SYSTEMATIC STUDIES COME TO COMPLETION. 2012 11 4571 36 MYELOMONOCYTIC SKEWING IN CHRONIC MYELOMONOCYTIC LEUKEMIA: PHENOTYPIC, MOLECULAR AND BIOLOGIC FEATURES AND IMPACT ON SURVIVAL. 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 12 2277 41 EPIGENETIC REGULATION BY ASXL1 IN MYELOID MALIGNANCIES. MYELOID MALIGNANCIES ARE CLONAL HEMATOPOIETIC DISORDERS THAT ARE COMPRISED OF A SPECTRUM OF GENETICALLY HETEROGENEOUS DISORDERS, INCLUDING MYELODYSPLASTIC SYNDROMES (MDS), MYELOPROLIFERATIVE NEOPLASMS (MPN), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML), AND ACUTE MYELOID LEUKEMIA (AML). MYELOID MALIGNANCIES ARE CHARACTERIZED BY EXCESSIVE PROLIFERATION, ABNORMAL SELF-RENEWAL, AND/OR DIFFERENTIATION DEFECTS OF HEMATOPOIETIC STEM CELLS (HSCS) AND MYELOID PROGENITOR CELLS HEMATOPOIETIC STEM/PROGENITOR CELLS (HSPCS). MYELOID MALIGNANCIES CAN BE CAUSED BY GENETIC AND EPIGENETIC ALTERATIONS THAT PROVOKE KEY CELLULAR FUNCTIONS, SUCH AS SELF-RENEWAL, PROLIFERATION, BIASED LINEAGE COMMITMENT, AND DIFFERENTIATION. ADVANCES IN NEXT-GENERATION SEQUENCING LED TO THE IDENTIFICATION OF MULTIPLE MUTATIONS IN MYELOID NEOPLASMS, AND MANY NEW GENE MUTATIONS WERE IDENTIFIED AS KEY FACTORS IN DRIVING THE PATHOGENESIS OF MYELOID MALIGNANCIES. THE POLYCOMB PROTEIN ASXL1 WAS IDENTIFIED TO BE FREQUENTLY MUTATED IN ALL FORMS OF MYELOID MALIGNANCIES, WITH MUTATIONAL FREQUENCIES OF 20%, 43%, 10%, AND 20% IN MDS, CMML, MPN, AND AML, RESPECTIVELY. SIGNIFICANTLY, ASXL1 MUTATIONS ARE ASSOCIATED WITH A POOR PROGNOSIS IN ALL FORMS OF MYELOID MALIGNANCIES. THE FACT THAT ASXL1 MUTATIONS ARE ASSOCIATED WITH POOR PROGNOSIS IN PATIENTS WITH CMML, MDS, AND AML, POINTS TO THE POSSIBILITY THAT ASXL1 MUTATION IS A KEY FACTOR IN THE DEVELOPMENT OF MYELOID MALIGNANCIES. THIS REVIEW SUMMARIZES THE RECENT ADVANCES IN UNDERSTANDING MYELOID MALIGNANCIES WITH A SPECIFIC FOCUS ON ASXL1 MUTATIONS. 2023 13 6574 38 TREATMENT OF CHRONIC MYELOMONOCYTIC LEUKEMIA WITH 5-AZACYTIDINE: CASE REPORTS. EPIGENETIC THERAPY WITH HYPOMETHYLATING AGENT (5-AZACYTIDINE; AZA) IS COMMON IN THE MANAGEMENT OF SPECIFIC SUBTYPES OF MYELODYSPLASTIC SYNDROME (MDS), BUT THERE ARE ONLY FEW STUDIES IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) PATIENTS. IN THIS PAPER OUR EXPERIENCE WITH 3 CMML PATIENTS TREATED WITH AZA IS DESCRIBED. IN ONE PATIENT TRANSFUSION INDEPENDENCY WAS OBSERVED AFTER 4 TREATMENT CYCLES; IN ONE CASE A PARTIAL RESPONSE WAS RECORDED, BUT A PROGRESSION TO ACUTE MYELOID LEUKEMIA (AML) AFTER 13 AZA CYCLES HAS APPEARED. IN ONE PATIENT, AZA IN REDUCED DOSAGE WAS ADMINISTERED AS A BRIDGING TREATMENT BEFORE ALLOGENEIC STEM CELL TRANSPLANTATION (ASCT), BUT IN THE CONTROL BONE MARROW ASPIRATE (BEFORE ASCT) A PROGRESSION TO AML WAS RECORDED. FUTURE STUDIES ARE MANDATORY FOR EVALUATION OF NEW MOLECULAR AND CLINICAL FEATURES WHICH COULD PREDICT THE EFFICIENCY OF HYPOMETHYLATING AGENTS IN CMML THERAPY WITH RESPECT TO OVERALL SURVIVAL, EVENT-FREE SURVIVAL, QUALITY-ADJUSTED LIFE YEAR, AND PHARMACOECONOMY. 2012 14 5979 30 TET2 MUTATIONS ARE ASSOCIATED WITH SPECIFIC 5-METHYLCYTOSINE AND 5-HYDROXYMETHYLCYTOSINE PROFILES IN PATIENTS WITH CHRONIC MYELOMONOCYTIC LEUKEMIA. CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) HAS RECENTLY BEEN ASSOCIATED WITH A HIGH INCIDENCE OF DIVERSE MUTATIONS IN GENES SUCH AS TET2 OR EZH2 THAT ARE IMPLICATED IN EPIGENETIC MECHANISMS. WE HAVE PERFORMED GENOME-WIDE DNA METHYLATION ARRAYS AND MUTATIONAL ANALYSIS OF TET2, IDH1, IDH2, EZH2 AND JAK2 IN A GROUP OF 24 PATIENTS WITH CMML. 249 GENES WERE DIFFERENTIALLY METHYLATED BETWEEN CMML PATIENTS AND CONTROLS. USING INGENUITY PATHWAY ANALYSIS, WE IDENTIFIED ENRICHMENT IN A GENE NETWORK CENTERED AROUND PLC, JNK AND ERK SUGGESTING THAT THESE PATHWAYS, WHOSE DEREGULATION HAS BEEN RECENTLY DESCRIBED IN CMML, ARE AFFECTED BY EPIGENETIC MECHANISMS. MUTATIONS OF TET2, JAK2 AND EZH2 WERE FOUND IN 15 PATIENTS (65%), 4 PATIENTS (17%) AND 1 PATIENT (4%) RESPECTIVELY WHILE NO MUTATIONS IN THE IDH1 AND IDH2 GENES WERE IDENTIFIED. INTERESTINGLY, PATIENTS WITH WILD TYPE TET2 CLUSTERED SEPARATELY FROM PATIENTS WITH TET2 MUTATIONS, SHOWED A HIGHER DEGREE OF HYPERMETHYLATION AND WERE ASSOCIATED WITH HIGHER RISK KARYOTYPES. OUR RESULTS DEMONSTRATE THE PRESENCE OF ABERRANT DNA METHYLATION IN CMML AND IDENTIFIES TET2 MUTANT CMML AS A BIOLOGICALLY DISTINCT DISEASE SUBTYPE WITH A DIFFERENT EPIGENETIC PROFILE. 2012 15 536 33 ASXL1 MUTATIONS PREDICT INFERIOR MOLECULAR RESPONSE TO NILOTINIB TREATMENT IN CHRONIC MYELOID LEUKEMIA. GENE MUTATIONS INDEPENDENT OF BCR::ABL1 HAVE BEEN IDENTIFIED IN NEWLY DIAGNOSED PATIENTS WITH CHRONIC MYELOID LEUKEMIA (CML) IN CHRONIC PHASE, WHEREBY MUTATIONS IN EPIGENETIC MODIFIER GENES WERE MOST COMMON. THESE FINDINGS PROMPTED THE SYSTEMATIC ANALYSIS OF PREVALENCE, DYNAMICS, AND PROGNOSTIC SIGNIFICANCE OF SUCH MUTATIONS, IN A CLINICALLY WELL-CHARACTERIZED PATIENT POPULATION OF 222 CML PATIENTS FROM THE TIGER STUDY (CML-V) BY TARGETED NEXT-GENERATION SEQUENCING COVERING 54 MYELOID LEUKEMIA-ASSOCIATED GENES. IN TOTAL, 53/222 CML PATIENTS (24%) CARRIED 60 MUTATIONS AT DIAGNOSIS WITH ASXL1 BEING MOST COMMONLY AFFECTED (N = 20). TO STUDY MUTATION DYNAMICS, LONGITUDINAL DEEP SEQUENCING ANALYSIS OF SERIAL SAMPLES WAS PERFORMED IN 100 PATIENTS AFTER 12, 24, AND 36 MONTHS OF THERAPY. TYPICAL PATTERNS OF CLONAL EVOLUTION INCLUDED ERADICATION, PERSISTENCE, AND EMERGENCE OF MUTATED CLONES. PATIENTS CARRYING AN ASXL1 MUTATION AT DIAGNOSIS SHOWED A LESS FAVORABLE MOLECULAR RESPONSE TO NILOTINIB TREATMENT, AS A MAJOR MOLECULAR RESPONSE (MMR) WAS ACHIEVED LESS FREQUENTLY AT MONTH 12, 18, AND 24 COMPARED TO ALL OTHER PATIENTS. PATIENTS WITH ASXL1 MUTATIONS WERE ALSO YOUNGER AND MORE FREQUENTLY FOUND IN THE HIGH RISK CATEGORY, SUGGESTING A CENTRAL ROLE OF CLONAL EVOLUTION ASSOCIATED WITH ASXL1 MUTATIONS IN CML PATHOGENESIS. 2022 16 4485 35 MOLECULAR SIMILARITY BETWEEN MYELODYSPLASTIC FORM OF CHRONIC MYELOMONOCYTIC LEUKEMIA AND REFRACTORY ANEMIA WITH RING SIDEROBLASTS. CHRONIC MYELOMONOCYTIC LEUKEMIA IS SIMILAR TO BUT A SEPARATE ENTITY FROM BOTH MYELOPROLIFERATIVE NEOPLASMS AND MYELODYSPLASTIC SYNDROMES, AND SHOWS EITHER MYELOPROLIFERATIVE OR MYELODYSPLASTIC FEATURES. WE ASK WHETHER THIS DISTINCTION MAY HAVE A MOLECULAR BASIS. WE ESTABLISHED THE GENE EXPRESSION PROFILES OF 39 SAMPLES OF CHRONIC MYELOMONOCYTIC LEUKEMIA (INCLUDING 12 CD34-POSITIVE) AND 32 CD34-POSITIVE SAMPLES OF MYELODYSPLASTIC SYNDROMES BY USING AFFYMETRIX MICROARRAYS, AND STUDIED THE STATUS OF 18 GENES BY SANGER SEQUENCING AND ARRAY-COMPARATIVE GENOMIC HYBRIDIZATION IN 53 SAMPLES. ANALYSIS OF 12 MRNAS FROM CHRONIC MYELOMONOCYTIC LEUKEMIA ESTABLISHED A GENE EXPRESSION SIGNATURE OF 122 PROBE SETS DIFFERENTIALLY EXPRESSED BETWEEN PROLIFERATIVE AND DYSPLASTIC CASES OF CHRONIC MYELOMONOCYTIC LEUKEMIA. AS COMPARED TO PROLIFERATIVE CASES, DYSPLASTIC CASES OVER-EXPRESSED GENES INVOLVED IN RED BLOOD CELL BIOLOGY. WHEN APPLIED TO 32 MYELODYSPLASTIC SYNDROMES, THIS GENE EXPRESSION SIGNATURE WAS ABLE TO DISCRIMINATE REFRACTORY ANEMIAS WITH RING SIDEROBLASTS FROM REFRACTORY ANEMIAS WITH EXCESS OF BLASTS. BY COMPARING MRNAS FROM THESE TWO FORMS OF MYELODYSPLASTIC SYNDROMES WE DERIVED A SECOND GENE EXPRESSION SIGNATURE. THIS SIGNATURE SEPARATED THE MYELODYSPLASTIC AND MYELOPROLIFERATIVE FORMS OF CHRONIC MYELOMONOCYTIC LEUKEMIAS. THESE RESULTS WERE VALIDATED USING TWO INDEPENDENT GENE EXPRESSION DATA SETS. WE FOUND THAT MYELODYSPLASTIC CHRONIC MYELOMONOCYTIC LEUKEMIAS ARE CHARACTERIZED BY MUTATIONS IN TRANSCRIPTION/EPIGENETIC REGULATORS (ASXL1, RUNX1, TET2) AND SPLICING GENES (SRSF2) AND THE ABSENCE OF MUTATIONS IN SIGNALING GENES. MYELODYSPLASTIC CHRONIC MYELOMONOCYTIC LEUKEMIAS AND REFRACTORY ANEMIAS WITH RING SIDEROBLASTS SHARE A COMMON EXPRESSION PROGRAM SUGGESTING THEY ARE PART OF A CONTINUUM, WHICH IS NOT TOTALLY EXPLAINED BY THEIR SIMILAR BUT NOT, HOWEVER, IDENTICAL MUTATION SPECTRUM. 2013 17 32 47 A CASE OF TYROSINE KINASE INHIBITOR-RESISTANT CHRONIC MYELOID LEUKEMIA, CHRONIC PHASE WITH ASXL1 MUTATION. HEMATOLOGICAL MALIGNANCIES, INCLUDING CHRONIC MYELOID LEUKEMIA (CML), EXHIBIT ASXL1 MUTATIONS; HOWEVER, THE FUNCTION AND MOLECULAR MECHANISM OF THESE MUTATIONS REMAIN UNCLEAR. ASXL1 WAS ORIGINALLY IDENTIFIED AS TUMOR SUPPRESSOR GENE, IN WHICH LOSS OF FUNCTION CAUSES MYELODYSPLASTIC SYNDROME (MDS). ASXL1 MUTATIONS ARE COMMON AND ASSOCIATED WITH DISEASE PROGRESSION IN MYELOID MALIGNANCIES INCLUDING MDS, ACUTE MYELOID LEUKEMIA, AND SIMILARLY IN CML. IN MDS, ASXL1 MUTATIONS HAVE BEEN ASSOCIATED WITH POOR PROGNOSIS; HOWEVER, THE IMPACT OF ASXL1 MUTATIONS IN CML HAS NOT BEEN WELL DESCRIBED. A 31-YEAR-OLD MALE WAS DIAGNOSED AS CML-CHRONIC PHASE (CP). LABORATORY FINDINGS SHOWED A WHITE BLOOD CELL COUNT OF 187,200/MICROL, WITH ASYMPTOMATIC SPLENOMEGALY. BLAST COUNT WAS 5.0% IN PERIPHERAL BLOOD AND 7.3% IN BONE MARROW. THERE WAS NO ADDITIONAL CHROMOSOMAL ABNORMALITY EXCEPT FOR T(9;22)(Q34;Q11.2) BY CHROMOSOMAL ANALYSIS. AT ONSET, THE SOKAL SCORE WAS 1.4, INDICATING HIGH RISK. THE PATIENT RECEIVED TYROSINE KINASE INHIBITOR (TKI) THERAPY, COMPRISING NILOTINIB APPROXIMATELY 600 MG/DAY, BOSUTINIB APPROXIMATELY 600 MG/DAY, PONATINIB APPROXIMATELY 45 MG/DAY, AND DASATINIB APPROXIMATELY 100 MG/DAY. NEVERTHELESS, AFTER 1.5 YEARS OF CONTINUOUS TKI THERAPY, THE BEST OUTCOME WAS A HEMATOLOGICAL RESPONSE. ALTHOUGH ADDITIONAL CHROMOSOMAL ABERRATIONS AND ABL1 KINASE MUTATIONS WERE ANALYZED REPEATEDLY BEFORE AND DURING TKI THERAPY, KNOWN GENETIC ABNORMALITIES WERE NOT DETECTED. THEREAFTER, THE PATIENT UNDERWENT BONE MARROW TRANSPLANTATION FROM AN HLA 7/8 MATCHED UNRELATED DONOR (HLA-CW 1 LOCUS MISMATCH, GRAFT-VERSUS-HOST DIRECTION). THE PATIENT ACHIEVED NEUTROPHIL ENGRAFTMENT, 18 DAYS AFTER TRANSPLANTATION, LEADING TO COMPLETE REMISSION WITH AN UNDETECTABLE LEVEL OF BCR-ABL1 MRNA. THE PATIENT, HOWEVER, DIED FROM GRAFT-VERSUS-HOST DISEASE AND THROMBOTIC MICROANGIOPATHY AFTER 121 DAYS. GENE SEQUENCE ANALYSIS OF HIS CML CELL BEFORE STEM CELL TRANSPLANTATION REVEALED ASXL1 MUTATIONS. PHYSIOLOGICALLY, ASXL1 CONTRIBUTES TO EPIGENETIC REGULATION. IN THE CML-CP PATIENT IN THIS CASE REPORT, ASXL1 MUTATION CONFERRED RESISTANCE TO TKI THROUGH OBSCURE RESISTANCE MECHANISMS. EVEN THOUGH A MOLECULAR MECHANISM FOR TKI RESISTANCE IN ASXL1 MUTATION IN CML HAS REMAINED OBSCURE, EPIGENETIC MODULATION IS A PLAUSIBLE MODE OF CML DISEASE PROGRESSION. THE CLINICAL IMPACT INCLUDING PROGNOSIS OF ASXL1 FOR CML IS UNDERSCORED. AND THE TREATMENT STRATEGY OF CML WITH ASXL1 MUTATION HAS NOT BEEN ESTABLISHED. A DISCUSSION OF THIS CASE WAS EXPECTED TO FACILITATE TREATMENT OPTIONS. 2020 18 5911 29 TARGETED NEXT-GENERATION SEQUENCING IN MYELODYSPLASTIC SYNDROME AND CHRONIC MYELOMONOCYTIC LEUKEMIA AIDS DIAGNOSIS IN CHALLENGING CASES AND IDENTIFIES FREQUENT SPLICEOSOME MUTATIONS IN TRANSFORMED ACUTE MYELOID LEUKEMIA. OBJECTIVES: OPTIMAL INTEGRATION OF NEXT-GENERATION SEQUENCING (NGS) INTO CLINICAL PRACTICE IN HEMATOLOGIC MALIGNANCIES REMAINS UNCLEAR. WE EVALUATE THE UTILITY OF NGS IN MYELOID MALIGNANCIES. METHODS: A 42-GENE PANEL WAS USED TO SEQUENCE 109 CASES OF MYELODYSPLASTIC SYNDROME (MDS, N = 38), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML, N = 14), MYELOPROLIFERATIVE NEOPLASM (MPN, N = 24), AND MDS AND/OR MPN TRANSFORMED TO ACUTE MYELOID LEUKEMIA (AML, N = 33). RESULTS: AT LEAST ONE PATHOGENIC MUTATION WAS IDENTIFIED IN 74% OF CASES OF MDS, 100% OF CMMLS, AND 96% OF MPNS. IN CONTRAST, ONLY 47% OF CASES OF MDS (18/38) AND 7% (1/14) OF CMMLS EXHIBITED ABNORMAL CYTOGENETICS. IN DIAGNOSTICALLY DIFFICULT CASES OF MDS OR CMML WITH NORMAL CYTOGENETICS, NGS IDENTIFIED A PATHOGENIC MUTATION AND WAS CRITICAL IN ESTABLISHING THE CORRECT DIAGNOSIS. SPLICEOSOMAL GENES AND EPIGENETIC MODIFIERS WERE FREQUENTLY MUTATED. SPLICEOSOME MUTATIONS WERE ALSO FREQUENTLY DETECTED IN AML ARISING FROM MDS, CMML, OR MPN (39%) COMPARED WITH THE REPORTED RATE IN DE NOVO AML (7%-14%). CONCLUSIONS: IN DIFFICULT CASES OF MDS OR MPN, NGS FACILITATES DIAGNOSIS BY DETECTION OF GENE MUTATIONS TO CONFIRM CLONALITY, AND AMLS EVOLVING FROM MDS OR MPN CARRY FREQUENT MUTATIONS IN SPLICEOSOMAL GENES. 2016 19 3872 49 JUVENILE MYELOMONOCYTIC LEUKEMIA-A COMPREHENSIVE REVIEW AND RECENT ADVANCES IN MANAGEMENT. JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) IS A RARE PEDIATRIC MYELODYSPLASTIC/MYELOPROLIFERATIVE NEOPLASM OVERLAP DISEASE. JMML IS ASSOCIATED WITH MUTATIONS IN THE RAS PATHWAY GENES RESULTING IN THE MYELOID PROGENITORS BEING SENSITIVE TO GRANULOCYTE MONOCYTE COLONY-STIMULATING FACTOR (GM-CSF). KARYOTYPE ABNORMALITIES AND ADDITIONAL EPIGENETIC ALTERATIONS CAN ALSO BE FOUND IN JMML. NEUROFIBROMATOSIS AND NOONAN'S SYNDROME HAVE A PREDISPOSITION FOR JMML. IN A FEW PATIENTS, THE RAS GENES (NRAS, KRAS, AND PTPN11) ARE MUTATED AT THE GERMLINE AND THIS USUALLY RESULTS IN A TRANSIENT MYELOPROLIFERATIVE DISORDER WITH A GOOD PROGNOSIS. JMML WITH SOMATIC RAS MUTATION BEHAVES AGGRESSIVELY. JMML PRESENTS WITH CYTOPENIAS AND LEUKEMIC INFILTRATION INTO ORGANS. THE LABORATORY FINDINGS INCLUDE HYPERLEUKOCYTOSIS, MONOCYTOSIS, INCREASED HEMOGLOBIN-F LEVELS, AND CIRCULATING MYELOID PRECURSORS. THE BLAST CELLS IN THE PERIPHERAL BLOOD/BONE-MARROW ASPIRATE ARE LESS THAN 20% AND THE ABSENCE OF THE BCR-ABL TRANSLOCATION HELPS TO DIFFERENTIATE FROM CHRONIC MYELOID LEUKEMIA. JMML SHOULD BE DIFFERENTIATED FROM IMMUNODEFICIENCIES, VIRAL INFECTIONS, INTRAUTERINE INFECTIONS, HEMOPHAGOLYMPHOHISTIOCYTOSIS, OTHER MYELOPROLIFERATIVE DISORDERS, AND LEUKEMIAS. CHEMOTHERAPY IS EMPLOYED AS A BRIDGE TO HSCT, EXCEPT IN FEW WITH LESS AGGRESSIVE DISEASE, IN WHICH CHEMOTHERAPY ALONE CAN RESULT IN LONG TERM REMISSION. AZACITIDINE HAS SHOWN PROMISE AS A SINGLE AGENT TO STABILIZE THE DISEASE. THE PROGNOSIS OF JMML IS POOR WITH ABOUT 50% OF PATIENTS SURVIVING AFTER AN ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT). ALLOGENEIC HSCT IS THE ONLY KNOWN CURE FOR JMML TO DATE. MYELOABLATIVE CONDITIONING IS MOST COMMONLY USED WITH GRAFT VERSUS HOST DISEASE (GVHD) PROPHYLAXIS TAILORED TO THE AGGRESSIVENESS OF THE DISEASE. RELAPSES ARE COMMON EVEN AFTER HSCT AND A SECOND HSCT CAN SALVAGE A THIRD OF THESE PATIENTS. NOVEL OPTIONS IN THE TREATMENT OF JMML E.G., HYPOMETHYLATING AGENTS, MEK INHIBITORS, JAK INHIBITORS, TYROSINE KINASE INHIBITORS, ETC. ARE BEING EXPLORED. 2021 20 4565 32 MYELOID MALIGNANCIES: MUTATIONS, MODELS AND MANAGEMENT. MYELOID MALIGNANT DISEASES COMPRISE CHRONIC (INCLUDING MYELODYSPLASTIC SYNDROMES, MYELOPROLIFERATIVE NEOPLASMS AND CHRONIC MYELOMONOCYTIC LEUKEMIA) AND ACUTE (ACUTE MYELOID LEUKEMIA) STAGES. THEY ARE CLONAL DISEASES ARISING IN HEMATOPOIETIC STEM OR PROGENITOR CELLS. MUTATIONS RESPONSIBLE FOR THESE DISEASES OCCUR IN SEVERAL GENES WHOSE ENCODED PROTEINS BELONG PRINCIPALLY TO FIVE CLASSES: SIGNALING PATHWAYS PROTEINS (E.G. CBL, FLT3, JAK2, RAS), TRANSCRIPTION FACTORS (E.G. CEBPA, ETV6, RUNX1), EPIGENETIC REGULATORS (E.G. ASXL1, DNMT3A, EZH2, IDH1, IDH2, SUZ12, TET2, UTX), TUMOR SUPPRESSORS (E.G. TP53), AND COMPONENTS OF THE SPLICEOSOME (E.G. SF3B1, SRSF2). LARGE-SCALE SEQUENCING EFFORTS WILL SOON LEAD TO THE ESTABLISHMENT OF A COMPREHENSIVE REPERTOIRE OF THESE MUTATIONS, ALLOWING FOR A BETTER DEFINITION AND CLASSIFICATION OF MYELOID MALIGNANCIES, THE IDENTIFICATION OF NEW PROGNOSTIC MARKERS AND THERAPEUTIC TARGETS, AND THE DEVELOPMENT OF NOVEL THERAPIES. GIVEN THE IMPORTANCE OF EPIGENETIC DEREGULATION IN MYELOID DISEASES, THE USE OF DRUGS TARGETING EPIGENETIC REGULATORS APPEARS AS A MOST PROMISING THERAPEUTIC APPROACH. 2012