1 2426 134 EPIGENETIC SILENCING OF LONG NON-CODING RNA BM742401 IN MULTIPLE MYELOMA: IMPACT ON PROGNOSIS AND MYELOMA DISSEMINATION. BACKGROUND: LONG NON-CODING RNA (LNCRNA) BM742401 IS A TUMOR SUPPRESSOR IN GASTRIC CANCER AND CHRONIC LYMPHOCYTIC LEUKEMIA. AS THE PROMOTER AND CODING REGION OF BM742401 ARE FULLY EMBEDDED IN A CPG ISLAND, WE HYPOTHESIZED THAT BM742401 IS A TUMOR SUPPRESSOR LNCRNA EPIGENETICALLY SILENCED BY PROMOTER DNA METHYLATION IN MULTIPLE MYELOMA. METHODS: METHYLATION-SPECIFIC PCR AND QUANTITATIVE BISULFITE PYROSEQUENCING WERE PERFORMED TO DETECT THE METHYLATION OF BM742401 IN NORMAL PLASMA CELLS, MYELOMA CELL LINES AND PRIMARY MYELOMA SAMPLES. THE EXPRESSION OF BM742401 WAS MEASURED BY QRT-PCR. THE FUNCTION OF BM742401 IN MULTIPLE MYELOMA CELLS WAS ANALYZED BY LENTIVIRUS TRANSDUCTION FOLLOWED BY MIGRATION ASSAY. RESULTS: BM742401 METHYLATION WAS DETECTED IN 10 (66.7%) MYELOMA CELL LINES BUT NOT NORMAL PLASMA CELLS, AND INVERSELY CORRELATED WITH EXPRESSION OF BM742401. IN PRIMARY SAMPLES, BM742401 METHYLATION WAS DETECTED IN 3 (12.5%) MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE, 9 (15.8%) MYELOMA AT DIAGNOSIS AND 8 (17.0%) MYELOMA AT RELAPSE/PROGRESSION. MOREOVER, BM742401 METHYLATION AT DIAGNOSIS WAS ASSOCIATED WITH INFERIOR OVERALL SURVIVAL (MEDIAN OS: 25 VS. 39 MONTHS; P = 0.0496). IN MYELOMA CELL LINE JJN-3, STABLE OVEREXPRESSION OF BM742401 BY LENTIVIRUS TRANSDUCTION RESULTED IN REDUCED CELL MIGRATION (P = 0.0001) BUT NOT IMPACTING CELL DEATH OR PROLIFERATION. CONCLUSIONS: THIS IS THE FIRST REPORT OF TUMOR-SPECIFIC METHYLATION-MEDIATED SILENCING OF BM742401 IN MYELOMA, WHICH IS LIKELY AN EARLY EVENT IN MYELOMAGENESIS WITH ADVERSE IMPACT ON OVERALL SURVIVAL. MOREOVER, BM742401 IS A TUMOR SUPPRESSOR LNCRNA BY INHIBITING MYELOMA CELL MIGRATION, HENCE IMPLICATED IN MYELOMA PLASMA CELL HOMING, METASTASIS AND DISEASE PROGRESSION. 2020 2 2133 34 EPIGENETIC INACTIVATION OF THE MIR-34A IN HEMATOLOGICAL MALIGNANCIES. MIR-34A IS A TRANSCRIPTIONAL TARGET OF P53 AND IMPLICATED IN CARCINOGENESIS. WE STUDIED THE ROLE OF MIR-34A METHYLATION IN A PANEL OF HEMATOLOGICAL MALIGNANCIES INCLUDING ACUTE LEUKEMIA [ACUTE MYELOID LEUKEMIA (AML) AND ACUTE LYMPHOBLASTIC LEUKEMIA (ALL)], CHRONIC LEUKEMIA [CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AND CHRONIC MYELOID LEUKEMIA (CML)], MULTIPLE MYELOMA (MM) AND NON-HODGKIN'S LYMPHOMA (NHL). THE METHYLATION STATUS OF MIR-34A PROMOTER WAS STUDIED IN 12 CELL LINES AND 188 DIAGNOSTIC SAMPLES BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. MIR-34A PROMOTER WAS UNMETHYLATED IN NORMAL CONTROLS BUT METHYLATED IN 75% LYMPHOMA AND 37% MYELOMA CELL LINES. HYPOMETHYLATING TREATMENT LED TO RE-EXPRESSION OF PRI-MIR-34A TRANSCRIPT IN LYMPHOMA CELLS WITH HOMOZYGOUS MIR-34A METHYLATION. IN PRIMARY SAMPLES AT DIAGNOSIS, MIR-34A METHYLATION WAS DETECTED IN 4% CLL, 5.5% MM SAMPLES AND 18.8% OF NHL AT DIAGNOSIS BUT NONE OF ALL, AML AND CML (P = 0.011). IN MM PATIENTS WITH PAIRED SAMPLES, MIR-34A METHYLATION STATUS REMAINED UNCHANGED AT PROGRESSION. AMONGST LYMPHOID MALIGNANCIES, MIR-34A WAS PREFERENTIALLY METHYLATED IN NHL (P = 0.018), IN PARTICULAR NATURAL KILLER (NK)/T-CELL LYMPHOMA. IN CONCLUSION, AMONGST HEMATOLOGICAL MALIGNANCIES, MIR-34A METHYLATION IS PREFERENTIALLY HYPERMETHYLATED IN NHL, IN PARTICULAR NK/T-CELL LYMPHOMA, IN A TUMOR-SPECIFIC MANNER, THEREFORE THE ROLE OF MIR-34A IN LYMPHOMAGENESIS WARRANTS FURTHER STUDY. 2010 3 2132 41 EPIGENETIC INACTIVATION OF THE MIR-124-1 IN HAEMATOLOGICAL MALIGNANCIES. MIR-124-1 IS A TUMOUR SUPPRESSOR MICRORNA (MIR). EPIGENETIC DEREGULATION OF MIRS IS IMPLICATED IN CARCINOGENESIS. PROMOTER DNA METHYLATION AND HISTONE MODIFICATION OF MIR-124-1 WAS STUDIED IN 5 NORMAL MARROW CONTROLS, 4 LYMPHOMA, 8 MULTIPLE MYELOMA (MM) CELL LINES, 230 DIAGNOSTIC PRIMARY SAMPLES OF ACUTE MYELOID LEUKAEMIA (AML), ACUTE LYMPHOBLASTIC LEUKAEMIA (ALL), CHRONIC MYELOID LEUKAEMIA (CML), CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL), MM, AND NON-HODGKIN'S LYMPHOMA (NHL), AND 53 MM SAMPLES AT STABLE DISEASE OR RELAPSE. PROMOTER OF MIR-124-1 WAS UNMETHYLATED IN NORMAL CONTROLS BUT HOMOZYGOUSLY METHYLATED IN 4 OF 4 LYMPHOMA AND 4 OF 8 MYELOMA CELL LINES. TREATMENT OF 5-AZA-2'-DEOXYCYTIDINE LED TO MIR-124-1 DEMETHYLATION AND RE-EXPRESSION OF MATURE MIR-124, WHICH ALSO ASSOCIATED WITH EMERGENCE OF EUCHROMATIC TRIMETHYL H3K4 AND CONSEQUENT DOWNREGULATION OF CDK6 IN MYELOMA CELLS HARBORING HOMOZYGOUS MIR-124-1 METHYLATION. IN PRIMARY SAMPLES AT DIAGNOSIS, MIR-124-1 METHYLATION WAS ABSENT IN CML BUT DETECTED IN 2% EACH OF MM AT DIAGNOSIS AND RELAPSE/PROGRESSION, 5% ALL, 15% AML, 14% CLL AND 58.1% OF NHL (P<0.001). AMONGST LYMPHOID MALIGNANCIES, MIR-124-1 WAS PREFERENTIALLY METHYLATED IN NHL THAN MM, CLL OR ALL. IN PRIMARY LYMPHOMA SAMPLES, MIR-124-1 WAS PREFERENTIALLY HYPERMETHYLATED IN B- OR NK/T-CELL LYMPHOMAS AND ASSOCIATED WITH REDUCED MIR-124 EXPRESSION. IN CONCLUSION, MIR-124-1 WAS HYPERMETHYLATED IN A TUMOUR-SPECIFIC MANNER, WITH A HETEROCHROMATIC HISTONE CONFIGURATION. HYPOMETHYLATION LED TO PARTIAL RESTORATION OF EUCHROMATIC HISTONE CODE AND MIR RE-EXPRESSION. INFREQUENT MIR-124-1 METHYLATION DETECTED IN DIAGNOSTIC AND RELAPSE MM SAMPLES SHOWED AN UNIMPORTANT ROLE IN MM PATHOGENESIS, DESPITE FREQUENT METHYLATION FOUND IN CELL LINES. AMONGST HAEMATOLOGICAL CANCERS, MIR-124-1 WAS MORE FREQUENTLY HYPERMETHYLATED IN NHL, AND HENCE WARRANTS FURTHER STUDY. 2011 4 2131 41 EPIGENETIC INACTIVATION OF THE HSA-MIR-203 IN HAEMATOLOGICAL MALIGNANCIES. MIR-203 IS A TUMOUR SUPPRESSOR MICRORNA (MIRNA). WE STUDIED THE METHYLATION OF HSA-MIR-203 IN 150 SAMPLES INCLUDING ACUTE MYELOID LEUKAEMIA (AML), ACUTE LYMPHOBLASTIC LEUKAEMIA (ALL), CHRONIC MYELOID LEUKAEMIA (CML), CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) AND NON-HODGKIN'S LYMPHOMA (NHL) BY METHYLATION-SPECIFIC PCR, AND MIRNA EXPRESSION BY STEM-LOOP RT-QPCR. HSA-MIR-203 PROMOTER WAS UNMETHYLATED IN NORMAL CONTROLS BUT HOMOZYGOUSLY METHYLATED IN TWO AML AND FOUR LYMPHOMA CELL LINES, IN WHICH 5-AZA-2'-DEOXYCYTIDINE TREATMENT LED TO PROMOTER DEMETHYLATION AND MIR-203 RE-EXPRESSION. RESTORATION OF MIR-203 EXPRESSION IN LYMPHOMA CELLS INHIBITED CELLULAR PROLIFERATION AND INCREASED CELL DEATH, SUGGESTING AN INHERENT TUMOUR SUPPRESSOR ACTIVITY. IN PRIMARY SAMPLES, HSA-MIR-203 METHYLATION WAS ABSENT IN CML BUT DETECTED IN 5.0% ALL, 10.0% AML, 42.0% CLL AND 38.8% OF NHL (INCLUDING SIX [60.0%] NATURAL KILLER-CELL, NINE [40.9%] B-CELL AND FOUR [23.5%] T CELL NHL). MOREOVER, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH HYPERMETHYLATION OF HSA-MIR-34A, -124A AND -196B IN NHL BUT NOT CLL. IN CLL, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH A HIGHER PRESENTING HB LEVEL (P = 0.033). THE PROJECTED 10 YEAR OVERALL SURVIVAL OF THE CLL PATIENTS WAS 58.2%, WHICH WAS IMPACTED BY RAI STAGE AND HIGH-RISK KARYOTYPES BUT NOT HSA-MIR-203 METHYLATION. HSA-MIR-203 WAS MORE FREQUENTLY METHYLATED IN LYMPHOID THAN MYELOID MALIGNANCIES (P = 0.002). IN CONCLUSION, MIR-203, A TUMOUR SUPPRESSOR GENE, WAS HYPERMETHYLATED IN A TUMOUR-SPECIFIC MANNER WITH GENE SILENCING. HSA-MIR-203 WAS MORE FREQUENTLY HYPERMETHYLATED IN LYMPHOID THAN MYELOID MALIGNANCIES. IN NHL, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH CONCOMITANT METHYLATION OF OTHER TUMOUR SUPPRESSOR MIRNAS. THE FREQUENT HSA-MIR-203 METHYLATION IN LYMPHOID MALIGNANCIES SUGGESTED A PATHOGENETIC ROLE OF HSA-MIR-203 METHYLATION. 2011 5 2440 56 EPIGENETIC SILENCING OF TUMOR SUPPRESSOR LONG NON-CODING RNA BM742401 IN CHRONIC LYMPHOCYTIC LEUKEMIA. BM742401 IS A TUMOR SUPPRESSOR LNCRNA DOWNREGULATED IN GASTRIC CANCER. AS THE PROMOTER REGION AND THE ENTIRE TRANSCRIPT ARE EMBEDDED IN A CPG ISLAND, WE POSTULATED THAT BM742401 IS A TUMOR SUPPRESSOR LNCRNA INACTIVATED BY DNA METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THE PROMOTER OF BM742401 WAS UNMETHYLATED IN NORMAL CONTROLS INCLUDING THREE EACH OF NORMAL BONE MARROW, PERIPHERAL BLOOD BUFFY COATS, AND CD19-SORTED PERIPHERAL B-CELLS, BUT METHYLATED IN FOUR (57.1%) CLL CELL LINES. METHYLATION OF BM742401 CORRELATED INVERSELY WITH EXPRESSION. IN THE COMPLETELY METHYLATED WAC3CD5+ CLL CELLS, 5-AZA-2'-DEOXYCYTIDINE TREATMENT LED TO PROMOTER DEMETHYLATION AND RE-EXPRESSION OF BM742401 TRANSCRIPT. FUNCTIONALLY, STABLE OVEREXPRESSION OF BM742401 RESULTED IN INHIBITION OF CELLULAR PROLIFERATION AND ENHANCED APOPTOSIS THROUGH CASPASE-9-DEPENDENT INTRINSIC BUT NOT CASPASE-8-DEPENDENT EXTRINSIC APOPTOSIS PATHWAY, SUGGESTING A TUMOR SUPPRESSOR ROLE OF BM742401 IN CLL. IN PRIMARY CLL SAMPLES, METHYLATION OF BM742401 WAS DETECTED IN 43/98 (43.9%) OF PATIENTS. MOREOVER, AMONG CLL PATIENTS WITH STANDARD-RISK CYTOGENETIC ABERRATIONS, METHYLATION OF BM742401 CORRELATED WITH ADVANCED RAI STAGE (>/= STAGE 2)(P = 0.002). FURTHERMORE, BM742401 METHYLATION WAS ASSOCIATED WITH MIR-129-2 METHYLATION (P = 0.05). BM742401 IS A TUMOR SUPPRESSOR LNCRNA FREQUENTLY METHYLATED IN CLL. THE MECHANISM OF BM742401 AS A TUMOR SUPPRESSOR WARRANTS FURTHER STUDIES. 2016 6 5056 25 PHASE I TRIAL OF LOW DOSE DECITABINE TARGETING DNA HYPERMETHYLATION IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKAEMIA AND NON-HODGKIN LYMPHOMA: DOSE-LIMITING MYELOSUPPRESSION WITHOUT EVIDENCE OF DNA HYPOMETHYLATION. TARGETING ABERRANT DNA HYPERMETHYLATION IN CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) AND NON-HODGKIN LYMPHOMA (NHL) WITH DECITABINE MAY REVERSE EPIGENETIC SILENCING IN B-CELL MALIGNANCIES. TWENTY PATIENTS WERE ENROLLED IN TWO PHASE I TRIALS TO DETERMINE THE MINIMUM EFFECTIVE PHARMACOLOGICAL DOSE OF DECITABINE IN PATIENTS WITH RELAPSED/REFRACTORY CLL (N = 16) AND NHL (N = 4). PATIENTS RECEIVED 1-3 CYCLES OF DECITABINE. DOSE-LIMITING TOXICITY (DLT) WAS OBSERVED IN 2 OF 4 CLL AND 2 OF 2 NHL PATIENTS RECEIVING DECITABINE AT 15 MG/M(2) PER D DAYS 1-10, CONSISTING OF GRADE 3-4 THROMBOCYTOPENIA AND HYPERBILIRUBINAEMIA. SIX PATIENTS WITH CLL RECEIVED DECITABINE AT 10 MG/M(2) PER D DAYS 1-10 WITHOUT DLT; HOWEVER, RE-EXPRESSION OF METHYLATED GENES OR CHANGES IN GLOBAL DNA METHYLATION WERE NOT OBSERVED. THEREFORE, A 5-DAY DECITABINE SCHEDULE WAS EXAMINED. WITH 15 MG/M(2) PER D DECITABINE DAYS 1-5, DLT OCCURRED IN 2 OF 6 CLL AND 2 OF 2 NHL PATIENTS, CONSISTING OF GRADE 3-4 NEUTROPENIA, THROMBOCYTOPENIA, AND FEBRILE NEUTROPENIA. EIGHT PATIENTS HAD STABLE DISEASE. IN 17 PATIENTS, THERE WERE NO SIGNIFICANT CHANGES IN GENOME-WIDE METHYLATION OR IN TARGET GENE RE-EXPRESSION. IN CONCLUSION, DOSE-LIMITING MYELOSUPPRESSION AND INFECTIOUS COMPLICATIONS PREVENTED DOSE ESCALATION OF DECITABINE TO LEVELS ASSOCIATED WITH CHANGES IN GLOBAL METHYLATION OR GENE RE-EXPRESSION IN CLL AND NHL. 2010 7 4548 41 MUTATION ANALYSIS OF THE FAS AND TNFR APOPTOTIC CASCADE GENES IN HEMATOLOGICAL MALIGNANCIES. OBJECTIVE: THE EXISTENCE OF PROPERLY FUNCTIONING APOPTOTIC PATHWAYS IS OF UTMOST IMPORTANCE IN THE MAINTENANCE OF A NORMAL CELL COUNT. SEVERAL GROUPS HAVE SEARCHED FOR MUTATIONS IN THE FAS RECEPTOR, A WELL-CHARACTERIZED APOPTOTIC PROTEIN CARRYING A DEATH DOMAIN, AND REPORTED THE EXISTENCE OF RARE MUTATIONS IN MULTIPLE MYELOMA, T-ACUTE LYMPHOBLASTIC LEUKEMIA (T-ALL), AND ADULT T-CELL LEUKEMIA. OUR AIM WAS TO EXPAND THESE SEARCHES BY LOOKING FOR MUTATIONS IN THE DEATH DOMAINS OF FAS, FADD, TNFR, TRADD, AND RIP, IN THE PROMOTER REGION OF FAS, AND IN THE PROTEASE DOMAIN OF CASPASE 10, IN A LARGER VARIETY OF HEMATOLOGICAL MALIGNANCIES, SOME OF WHICH EXPRESS AN APOPTOSIS-RESISTANT PHENOTYPE. METHODS: WE EXTRACTED RNA AND DNA SAMPLES FROM 92 HEMATOLOGICAL MALIGNANCIES: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL; 31 CASES), CHRONIC MYELOGENOUS LEUKEMIA (CML; 28 CASES), ESSENTIAL THROMBOCYTHEMIA (ET; 8 CASES), ACUTE LYMPHOCYTIC LEUKEMIA (ALL; 6 CASES), ACUTE MYELOBLASTIC LEUKEMIA (AML; 6 CASES), HAIRY-CELL LEUKEMIA (HCL; 3 CASES), BURKITT'S LYMPHOMA (3 CASES), POLYCYTHEMIA VERA (PV; 3 CASES), MYELOFIBROSIS (2 CASES), AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML; 2 CASES) AND PERFORMED PCR-SSCP AND SEQUENCE ANALYSIS ON THESE SAMPLES. RESULTS: FIVE POLYMORPHIC PATTERNS WERE FOUND: THREE IN THE DEATH DOMAIN OF THE FAS GENE IN CML PATIENTS, ONE IN THE PROMOTER OF THIS GENE IN A CLL PATIENT, AND THE FIFTH IN THE DEATH DOMAIN OF THE TRADD GENE IN A CML PATIENT. NO MUTATIONS, ALTERING AMINO ACIDS, WERE FOUND IN THESE GENES IN ANY OF THE AFOREMENTIONED MALIGNANCIES. CONCLUSIONS: THESE OBSERVATIONS IMPLY THAT MUTATIONS IN THE DEATH DOMAINS OF FAS, FADD, TNFR, TRADD, AND RIP AND IN THE PROTEASE DOMAIN OF CASPASE 10 ARE NOT A MAJOR CAUSE FOR FAILURE OF APOPTOSIS IN HEMATOLOGICAL MALIGNANCIES, MAINLY CML AND CLL. REGULATORY AND EPIGENETIC ABNORMALITIES IN THESE APOPTOTIC CASCADE MEMBERS AND ABERRATIONS IN OTHER COMPONENTS OF ALL DEATH MACHINERY SHOULD BE LOOKED FOR. 2001 8 5462 27 RESEARCH PROGRESS ON EPIGENETICS OF SMALL B-CELL LYMPHOMA. SMALL B-CELL LYMPHOMA IS THE CLASSIFICATION OF B-CELL CHRONIC LYMPHOPROLIFERATIVE DISORDERS THAT INCLUDE CHRONIC LYMPHOCYTIC LEUKAEMIA/SMALL LYMPHOCYTIC LYMPHOMA, FOLLICULAR LYMPHOMA, MANTLE CELL LYMPHOMA, MARGINAL ZONE LYMPHOMA, LYMPHOPLASMACYTIC LYMPHOMA/WALDENSTROM MACROGLOBULINEMIA. THE CLINICAL PRESENTATION IS SOMEWHAT HETEROGENEOUS, AND ITS OCCURRENCE AND DEVELOPMENT MECHANISMS ARE NOT YET PRECISE AND MAY INVOLVE EPIGENETIC CHANGES. EPIGENETIC ALTERATIONS MAINLY INCLUDE DNA METHYLATION, HISTONE MODIFICATION, AND NON-CODING RNA, WHICH ARE ESSENTIAL FOR GENETIC DETECTION, EARLY DIAGNOSIS, AND ASSESSMENT OF TREATMENT RESISTANCE IN SMALL B-CELL LYMPHOMA. AS CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA HAS ALREADY BEEN REPORTED IN THE LITERATURE, THIS ARTICLE FOCUSES ON SMALL B-CELL LYMPHOMAS SUCH AS FOLLICULAR LYMPHOMA, MANTLE CELL LYMPHOMA, MARGINAL ZONE LYMPHOMA, AND WALDENSTROM MACROGLOBULINEMIA. IT DISCUSSES RECENT DEVELOPMENTS IN EPIGENETIC RESEARCH TO DIAGNOSE AND TREAT THIS GROUP OF LYMPHOMAS. THIS REVIEW PROVIDES NEW IDEAS FOR THE TREATMENT AND PROGNOSIS ASSESSMENT OF SMALL B-CELL LYMPHOMA BY EXPLORING THE CONNECTION BETWEEN SMALL B-CELL LYMPHOMA AND EPIGENETICS. 2022 9 5911 23 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 10 5055 34 PHASE 2 TRIAL OF THE HISTONE DEACETYLASE INHIBITOR ROMIDEPSIN FOR THE TREATMENT OF REFRACTORY MULTIPLE MYELOMA. BACKGROUND: EPIGENETIC DYSREGULATION IS A HALLMARK OF CANCER, INCLUDING MULTIPLE MYELOMA. INHIBITORS OF HISTONE DEACETYLASES (HDACS) INDUCE DNA HYPERACETYLATION BY INHIBITING REMOVAL OF ACETYL GROUPS FROM AMINO TAILS ON HISTONE PROTEINS, THEREBY UNCOILING CONDENSED CHROMATIN FAVORING TRANSCRIPTION OF SILENCED GENES, INCLUDING TUMOR SUPPRESSOR GENES. ROMIDEPSIN IS AN HDAC INHIBITOR THAT EXHIBITS ANTIPROLIFERATIVE AND APOPTOTIC EFFECTS AGAINST MULTIPLE MYELOMA CELL LINES. METHODS: A PHASE 2 TRIAL WAS PERFORMED OF ROMIDEPSIN IN PATIENTS WITH MULTIPLE MYELOMA WHO WERE REFRACTORY TO STANDARD THERAPY. TREATMENT WAS COMPRISED OF ROMIDEPSIN (13 MG/M(2)) GIVEN AS A 4-HOUR INTRAVENOUS INFUSION ON DAYS 1, 8, AND 15 EVERY 28 DAYS). THIRTEEN PATIENTS RECEIVED A MEDIAN OF 2 CYCLES OF THERAPY (RANGE, 1-7 CYCLES). RESULTS: ALTHOUGH NO PATIENTS HAD AN OBJECTIVE RESPONSE, 4 OF 12 PATIENTS WITH SECRETORY MYELOMA EXHIBITED EVIDENCE OF M-PROTEIN STABILIZATION, AND SEVERAL OTHER PATIENTS EXPERIENCED IMPROVEMENT IN BONE PAIN AND RESOLUTION OF HYPERCALCEMIA. CONCLUSIONS: THE RESULTS OF THE CURRENT STUDY DEMONSTRATE THAT ROMIDEPSIN, AS A SINGLE AGENT, IS UNLIKELY TO BE ASSOCIATED WITH A RESPONSE RATE OF >/=30% IN PATIENTS WITH REFRACTORY MYELOMA, ALTHOUGH THERE WAS SOME CLINICAL EVIDENCE SUGGESTING A BIOLOGICAL EFFECT ASSOCIATED WITH THERAPY. 2011 11 2971 24 GENETIC AND EPIGENETIC SILENCING OF MICRORNA-203 ENHANCES ABL1 AND BCR-ABL1 ONCOGENE EXPRESSION. THE MAMMALIAN GENOME CONTAINS SEVERAL HUNDRED MICRORNAS THAT REGULATE GENE EXPRESSION THROUGH MODULATION OF TARGET MRNAS. HERE, WE REPORT A FRAGILE CHROMOSOMAL REGION LOST IN SPECIFIC HEMATOPOIETIC MALIGNANCIES. THIS 7 MB REGION ENCODES ABOUT 12% OF ALL GENOMIC MICRORNAS, INCLUDING MIR-203. THIS MICRORNA IS ADDITIONALLY HYPERMETHYLATED IN SEVERAL HEMATOPOIETIC TUMORS, INCLUDING CHRONIC MYELOGENOUS LEUKEMIAS AND SOME ACUTE LYMPHOBLASTIC LEUKEMIAS. A PUTATIVE MIR-203 TARGET, ABL1, IS SPECIFICALLY ACTIVATED IN THESE HEMATOPOIETIC MALIGNANCIES IN SOME CASES AS A BCR-ABL1 FUSION PROTEIN (PHILADELPHIA CHROMOSOME). RE-EXPRESSION OF MIR-203 REDUCES ABL1 AND BCR-ABL1 FUSION PROTEIN LEVELS AND INHIBITS TUMOR CELL PROLIFERATION IN AN ABL1-DEPENDENT MANNER. THUS, MIR-203 FUNCTIONS AS A TUMOR SUPPRESSOR, AND RE-EXPRESSION OF THIS MICRORNA MIGHT HAVE THERAPEUTIC BENEFITS IN SPECIFIC HEMATOPOIETIC MALIGNANCIES. 2008 12 5278 37 PROMOTER METHYLATION-MEDIATED INACTIVATION OF PCDH10 IN ACUTE LYMPHOBLASTIC LEUKEMIA CONTRIBUTES TO CHEMOTHERAPY RESISTANCE. PCDH10 HAS BEEN IMPLICATED AS A TUMOR SUPPRESSOR, SINCE EPIGENETIC ALTERATIONS OF THIS GENE HAVE BEEN NOTED IN MULTIPLE TUMOR TYPES. HOWEVER, TO DATE, STUDIES REGARDING ITS ROLE IN ACUTE AND CHRONIC LEUKEMIAS ARE LACKING. HERE, WE HAVE INVESTIGATED THE PRESENCE OF PROMOTER HYPERMETHYLATION OF TWO CPG ISLANDS OF THE PCDH10 GENE BY METHYLATION-SPECIFIC PCR IN 215 CASES OF VARIOUS SUBSETS OF MYELOID- AND LYMPHOID-LINEAGE LEUKEMIAS. WE FOUND THAT PCDH10 PROMOTER HYPERMETHYLATION WAS FREQUENT IN BOTH B-CELL (81.9%) AND T-CELL (80%) ACUTE LYMPHOBLASTIC LEUKEMIA (ALL), WHILE IT WAS PRESENT IN LOW FREQUENCY IN MOST SUBTYPES OF MYELOID LEUKEMIAS (25.9%) AND RARE IN CHRONIC MYELOID LEUKEMIA (2.2%). PCDH10 EXPRESSION WAS DOWNREGULATED VIA PROMOTER HYPERMETHYLATION IN PRIMARY ALL SAMPLES (N = 4) AND LEUKEMIA CELL LINES (N = 11). THE TRANSCRIPTIONAL REPRESSION CAUSED BY PCDH10 METHYLATION COULD BE RESTORED BY PHARMACOLOGIC INHIBITION OF DNA METHYLTRANSFERASES. ALL CELL LINES HARBORING METHYLATION-MEDIATED INACTIVATION OF PCDH10 WERE LESS SENSITIVE TO COMMONLY USED LEUKEMIA-SPECIFIC DRUGS SUGGESTING THAT PCDH10 METHYLATION MIGHT SERVE AS A BIOMARKER OF CHEMOTHERAPY RESPONSE. OUR RESULTS DEMONSTRATE THAT PCDH10 IS A TARGET OF EPIGENETIC SILENCING IN ALL, A PHENOMENON THAT MAY IMPACT LYMPHOID-LINEAGE LEUKEMOGENESIS, SERVE AS AN INDICATOR OF DRUG RESISTANCE AND MAY ALSO HAVE POTENTIAL IMPLICATIONS FOR TARGETED EPIGENETIC THERAPY. 2011 13 2277 27 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 14 6383 26 THE ROLE OF PHF6 IN HEMATOPOIESIS AND HEMATOLOGIC MALIGNANCIES. EPIGENETIC REGULATION OF GENE EXPRESSION REPRESENTS AN IMPORTANT MECHANISM IN THE MAINTENANCE OF STEM CELL FUNCTION. ALTERATIONS IN EPIGENETIC REGULATION CONTRIBUTE TO THE PATHOGENESIS OF HEMATOLOGICAL MALIGNANCIES. PLANT HOMEODOMAIN FINGER PROTEIN 6 (PHF6) IS A MEMBER OF THE PLANT HOMEODOMAIN (PHD)-LIKE ZINC FINGER FAMILY OF PROTEINS THAT IS INVOLVED IN TRANSCRIPTIONAL REGULATION THROUGH THE MODIFICATION OF THE CHROMATIN STATE. GERMLINE MUTATION OF PHF6 IS THE CAUSATIVE GENETIC ALTERATION OF THE X-LINKED MENTAL RETARDATION BORJESON-FORSSMAN-LEHMANN SYNDROME (BFLS). SOMATIC MUTATIONS IN PHF6 ARE IDENTIFIED IN HUMAN LEUKEMIA, SUCH AS ADULT T-CELL ACUTE LYMPHOBLASTIC LEUKEMIA (T-ALL, ~ 38%), PEDIATRIC T-ALL (~ 16%), ACUTE MYELOID LEUKEMIA (AML, ~ 3%), CHRONIC MYELOID LEUKEMIA (CML, ~ 2.5%), MIXED PHENOTYPE ACUTE LEUKEMIA (MPAL, ~ 20%), AND HIGH-GRADE B-CELL LYMPHOMA (HGBCL, ~ 3%). MORE RECENT STUDIES IMPLY AN ONCOGENIC EFFECT OF PHF6 IN B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA (B-ALL) AND SOLID TUMORS. THESE DATA DEMONSTRATE THAT PHF6 COULD ACT AS A DOUBLE-EDGED SWORD, EITHER A TUMOR SUPPRESSOR OR AN ONCOGENE, IN A LINEAGE-DEPENDENT MANNER. HOWEVER, THE UNDERLYING MECHANISMS OF PHF6 IN NORMAL HEMATOPOIESIS AND LEUKEMOGENESIS REMAIN LARGELY UNKNOWN. IN THIS REVIEW, WE SUMMARIZE CURRENT KNOWLEDGE OF PHF6, EMPHASIZING THE ROLE OF PHF6 IN HEMATOLOGICAL MALIGNANCIES. EPIGENETIC REGULATION OF PHF6 IN B-ALL. PHF6 MAINTAINS A CHROMATIN STRUCTURE THAT IS PERMISSIVE TO B-CELL IDENTITY GENES, BUT NOT T-CELL-SPECIFIC GENES (LEFT). LOSS OF PHF6 LEADS TO ABERRANT EXPRESSION OF B-CELL- AND T-CELL-SPECIFIC GENES RESULTING FROM LINEAGE PROMISCUITY AND BINDING OF T-CELL TRANSCRIPTION FACTORS (RIGHT). 2023 15 2126 54 EPIGENETIC INACTIVATION OF MIR-34B/C IN ADDITION TO MIR-34A AND DAPK1 IN CHRONIC LYMPHOCYTIC LEUKEMIA. BACKGROUND: TP53 MUTATION/DELETION IS UNCOMMON IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). WE POSTULATED THAT COMPONENTS OF TP53-CENTERED TUMOR SUPPRESSOR NETWORK, MIR-34B/C, IN ADDITION TO DAPK1 AND MIR-34A MIGHT BE INACTIVATED BY DNA HYPERMETHYLATION. MOREOVER, WE TESTED IF MIR-34B/C METHYLATION MIGHT CORRELATE WITH MIR-203 OR MIR-124-1 METHYLATION IN CLL. METHODS: MIR-34B/C, MIR-34A AND DAPK1 METHYLATION WAS STUDIED IN 11 NORMAL CONTROLS, 7 CLL CELL LINES, AND 78 DIAGNOSTIC CLL SAMPLES BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. MEC-1 CELLS WERE TREATED WITH 5-AZA-2'-DEOXYCYTIDINE FOR REVERSAL OF METHYLATION-ASSOCIATED MIRNA SILENCING. TUMOR SUPPRESSOR PROPERTIES OF MIR-34B WERE DEMONSTRATED BY OVER-EXPRESSION OF PRECURSOR MIR-34B IN MEC-1 CELLS. RESULTS: MIR-34B/C PROMOTER WAS UNMETHYLATED IN NORMAL CONTROLS, BUT COMPLETELY METHYLATED IN 4 CLL CELL LINES. MIR-34B/C EXPRESSION WAS INVERSELY CORRELATED WITH MIR-34B/C METHYLATION. DIFFERENT MSP STATUSES OF MIR-34B/C, INCLUDING COMPLETE METHYLATION AND COMPLETE UNMETHYLATION, WERE VERIFIED BY QUANTITATIVE BISULFITE PYROSEQUENCING. 5-AZA-2'-DEOXYCYTIDINE TREATMENT RESULTED IN PROMOTER DEMETHYLATION AND MIR-34B RE-EXPRESSION IN MEC1 CELLS. MOREOVER, OVER-EXPRESSION OF MIR-34B RESULTED IN INHIBITION OF CELLULAR PROLIFERATION AND INCREASED CELL DEATH. IN PRIMARY CLL SAMPLES, MIR-34A, MIR-34B/C AND DAPK1 METHYLATION WAS DETECTED IN 2.6%, 17.9% AND 34.6% OF PATIENTS AT DIAGNOSIS RESPECTIVELY. FURTHERMORE, 39.7%, 3.8% AND 2.6% PATIENTS HAD METHYLATION OF ONE, TWO OR ALL THREE GENES RESPECTIVELY. OVERALL, 46.2% PATIENTS HAD METHYLATION OF AT LEAST ONE OF THESE THREE GENES. BESIDES, MIR-34B/C METHYLATION WAS ASSOCIATED WITH METHYLATION OF MIR-34A (P = 0.03) AND MIR-203 (P = 0.012) IN CLL. CONCLUSIONS: TAKEN TOGETHER, MIR-34B/C IS A TUMOR SUPPRESSOR MIRNA FREQUENTLY METHYLATED, AND HENCE SILENCED IN CLL. TOGETHER WITH DAPK1 METHYLATION, MIR-34B/C METHYLATION IS IMPLICATED IN THE DISRUPTION OF THE TP53-CENTERED TUMOR SUPPRESSOR NETWORK. MOREOVER, THE ASSOCIATION OF MIRNA METHYLATION WARRANTS FURTHER STUDY. 2014 16 4557 16 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 17 5274 18 PROMOTER METHYLATION OF P16 AND EDNRB GENE IN LEUKEMIA PATIENTS IN TAIWAN. BOTH EPIGENETIC AND GENETIC ALTERNATIONS ARE INVOLVED IN CANCER FORMATION. IN THIS STUDY, WE HAVE IDENTIFIED THE METHYLATION FREQUENCY OF P16 AND ENDOTHELIN RECEPTOR TYPE B (EDNRB) OF 26 LEUKEMIA PATIENTS AND 8 RANDOMLY SELECTED NORMAL BLOOD DONORS IN TAIWAN. PROMOTER METHYLATION OF P16 WAS DETECTED IN 85% OF ACUTE LYMPHOCYTIC LEUKEMIA (ALL), 83% IN ACUTE MYELOID LEUKEMIA (AML) WHEREAS NO METHYLATION WAS DETECTED IN CHRONIC MYELOID LEUKEMIA (CML) IN BLAST CRISIS. HYPERMETHYLATION OF EDNRB WAS OBSERVED IN 92% OF ALL, 75% AML AND 100% IN CML IN BLAST CRISIS. NO ABERRANT METHYLATION OF P16 AND EDNRB WAS FOUND IN 8 NORMAL BLOOD DONORS. TAKEN TOGETHER, ABERRANT METHYLATION OF P16 AND EDNRB WAS HIGHLY PREVALENT IN LEUKEMIA PATIENTS IN TAIWAN. 2008 18 205 26 ACTIVATION OF HLA-G EXPRESSION BY 5-AZA-2 - DEOXYCYTIDINE IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM LEUKEMIA PATIENTS. HUMAN LEUKOCYTE ANTIGEN - G (HLA-G) IS A NON-CLASSICAL HLA CLASS I ANTIGEN WITH RESTRICTED DISTRIBUTION IN NORMAL TISSUES. ECTOPIC HLA-G EXPRESSION OBSERVED AT SOME PATHOLOGICAL CIRCUMSTANCES AS MALIGNANT TRANSFORMATION MIGHT BE TRIGGERED BY EPIGENETIC MODIFICATIONS SUCH AS DNA DEMETHYLATION. RECENTLY IT WAS DEMONSTRATED THAT DNA METHYLTRANSFERASE INHIBITOR 5-AZA-2 - DEOXYCYTIDINE (ADC) INDUCES/ENHANCES HLA-G TRANSCRIPTION IN MANY LEUKEMIA CELL LINES OF DIFFERENT ORIGIN. HERE WE INVESTIGATED THE EFFECT OF ADC ON HLA-G EXPRESSION IN MALIGNANT HEMATOPOETIC CELLS ISOLATED FROM PATIENTS WITH ACUTE MYELOID LEUKEMIA (AML) AND CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL). WE DETECTED HLA-G EXPRESSION IN UNTREATED CELLS FROM SOME PATIENTS. NEVERTHELESS TREATMENT WITH 5-AZA-2 - DEOXYCYTIDINE ENHANCED HLA-G TRANSCRIPTION AND CONCOMITANTLY HLA-G PROTEIN SYNTHESIS IN SOME LEUKEMIA CELLS. 2009 19 2760 27 EXPRESSION OF PD-L1, PD-L2, PD-1 AND CTLA4 IN MYELODYSPLASTIC SYNDROMES IS ENHANCED BY TREATMENT WITH HYPOMETHYLATING AGENTS. BLOCKADE OF IMMUNE CHECKPOINTS IS EMERGING AS A NEW FORM OF ANTICANCER THERAPY. WE STUDIED THE EXPRESSION OF PROGRAMMED DEATH LIGAND 1 (PD-L1), PD-L2, PROGRAMMED DEATH 1 (PD-1) AND CYTOTOXIC T LYMPHOCYTE-ASSOCIATED ANTIGEN 4 (CTLA4) MRNA IN CD34+ CELLS FROM MYELODYSPLASTIC SYNDROME (MDS), CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AND ACUTE MYELOID LEUKEMIA (AML) PATIENTS (N=124). ABERRANT UPREGULATION (?2-FOLD) WAS OBSERVED IN 34, 14, 15 AND 8% OF THE PATIENTS. INCREASED EXPRESSION OF THESE FOUR GENES WAS ALSO OBSERVED IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMNCS) (N=61). THE RELATIVE EXPRESSION OF PD-L1 FROM PBMNC WAS SIGNIFICANTLY HIGHER IN MDS (P=0.018) AND CMML (P=0.0128) COMPARED WITH AML. BY IMMUNOHISTOCHEMICAL ANALYSIS, PD-L1 PROTEIN EXPRESSION WAS OBSERVED IN MDS CD34+ CELLS, WHEREAS STROMA/NON-BLAST CELLULAR COMPARTMENT WAS POSITIVE FOR PD-1. IN A COHORT OF PATIENTS TREATED WITH EPIGENETIC THERAPY, PD-L1, PD-L2, PD-1 AND CTLA4 EXPRESSION WAS UPREGULATED. PATIENTS RESISTANT TO THERAPY HAD RELATIVE HIGHER INCREMENTS IN GENE EXPRESSION COMPARED WITH PATIENTS WHO ACHIEVED RESPONSE. TREATMENT OF LEUKEMIA CELLS WITH DECITABINE RESULTED IN A DOSE-DEPENDENT UPREGULATION OF ABOVE GENES. EXPOSURE TO DECITABINE RESULTED IN PARTIAL DEMETHYLATION OF PD-1 IN LEUKEMIA CELL LINES AND HUMAN SAMPLES. THIS STUDY SUGGESTS THAT PD-1 SIGNALING MAY BE INVOLVED IN MDS PATHOGENESIS AND RESISTANCE MECHANISMS TO HYPOMETHYLATING AGENTS. BLOCKADE OF THIS PATHWAY CAN BE A POTENTIAL THERAPY IN MDS AND AML. 2014 20 6529 34 TRANSCRIPTIONAL DOWN-REGULATION OF THE WNT ANTAGONIST SFRP1 IN HAEMATOPOIETIC CELLS OF PATIENTS WITH DIFFERENT RISK TYPES OF MDS. SECRETED FRIZZLED RELATED PROTEIN 1 (SFRP1) IS AN EXTRACELLULAR ANTAGONIST OF THE WNT SIGNALLING PATHWAY THAT PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SOLID TUMOURS AND HAEMATOPOIETIC MALIGNANCIES. SFRP1 HAS BEEN OBSERVED TO BE TRANSCRIPTIONALLY DOWN-REGULATED DUE TO HYPERMETHYLATION IN ACUTE AND CHRONIC LEUKAEMIA, BUT SO FAR NOT IN MYELODYSPLASTIC SYNDROME (MDS). MOREOVER, IT HAS BEEN SHOWN THAT THE EPIGENETIC INACTIVATION OF SFRP1 CORRELATES WITH AN OVEREXPRESSION OF THE WNT RECEPTOR FRIZZLED 3 (FZD3) IN ACUTE LEUKAEMIA. USING REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION (RT-PCR) WE EXAMINED MRNA EXPRESSION OF SFRP1 AND FZD3 IN BONE MARROW CELLS DERIVED FROM 121 PATIENTS WITH DIFFERENT RISK TYPES OF MDS, ACUTE MYELOID LEUKAEMIA (AML) AND ACUTE LYMPHOBLASTIC LEUKAEMIA (ALL). WE EMPLOYED PYROSEQUENCING TO QUANTIFY PROMOTER DNA METHYLATION IN MDS AND ACUTE LEUKAEMIA. WE DETECTED SIGNIFICANT LOWER MRNA TRANSCRIPTION OF SFRP1 IN MDS COMPARED TO HEALTHY INDIVIDUALS. HOWEVER, DNA SEQUENCE MUTATIONS OR FREQUENT ELEVATED DNA METHYLATION LEVELS OF THE SFRP1 PROMOTER COULD NOT BE OBSERVED IN MDS BUT IN AML AND ALL AS PREVIOUSLY REPORTED. THE EXPRESSION LEVELS OF FZD3 WERE UP-REGULATED IN BOTH ACUTE LEUKAEMIA AND MDS. OUR DATA SHOW A SIGNIFICANT TRANSCRIPTIONAL DOWN-REGULATION OF SFRP1 AS A COMMON EVENT IN AML, ALL AND - AS DEMONSTRATED FOR THE FIRST TIME - IN MDS. AN INACTIVATION OF SFRP1 AND THE TRANSCRIPTIONAL UP-REGULATION OF FZD3 SEEM TO BE ASSOCIATED WITH AN ACTIVATION OF THE WNT SIGNALLING PATHWAY IN THESE HAEMATOPOIETIC DISEASES. 2010