1 6831 132 [HYPERMETHYLATION OF DAP-KINASE GENE CPG ISLAND IN MALIGNANT LYMPHOMA WITH B-CELL PHENOTYPE]. DEATH-ASSOCIATED PROTEIN-KINASE(DAP-KINASE) IS A PRO-APOPTOTIC SERINE/THREONINE KINASE WITH A DEATH DOMAIN, WHICH IS INVOLVED IN APOPTOSIS INDUCED BY INTERFERON-GAMMA, TUMOR NECROSIS FACTOR-ALPHA, AND FAS LIGAND. EPIGENETIC DOWN-REGULATION OF DAP-KINASE GENE EXPRESSION BY HYPERMETHYLATION OF ITS PROMOTER REGION WAS REPORTED IN CERTAIN KINDS OF MALIGNANCIES. PREVIOUS PATHO-EPIDEMIOLOGICAL STUDIES INDICATED THAT THYROID LYMPHOMA(TL) EVOLVES AMONG ACTIVE LYMPHOID CELLS IN CHRONIC LYMPHOCYTIC THYROIDITIS(CLTH). WITH THE USE OF METHYLATION SPECIFIC POLYMERASE CHAIN REACTION, METHYLATION STATUS OF DAP-KINASE CPG ISLAND WAS EXAMINED IN THYROID LESIONS OF 19 CASES WITH TL AND 9 WITH CLTH. FREQUENCY OF METHYLATION WAS HIGHER IN TL CASES(16 OF 19, 84.2%) THAN IN CLTH CASES(2 OF 9, 22.2%) (P < 0.01). DNA EXTRACTED FROM PERIPHERAL BLOOD LEUKOCYTES FROM TL AND CLTH CASES NEVER SHOWED METHYLATION, INDICATING THAT THE METHYLATION OCCURRED SOMATICALLY IN LESIONAL LYMPHOCYTES IN THE THYROID. WE ALSO EXAMINED THE METHYLATION STATUS OF DAP-KINASE GENE IN 16 CASES OF T-CELL MALIGNANCIES INCLUDING EIGHT ADULT T-CELL LEUKEMIA/LYMPHOMA AND 24 NK/T-CELL, 34 B-CELL, AND TWO IMMUNOPHENOTYPICALLY UNDETERMINED LYMPHOMAS. FREQUENCY OF METHYLATION WAS HIGHER IN B-CELL(27 OF 34, 79.4%) THAN IN T-CELL MALIGNANCIES(EIGHT OF 16, 50%) (P < 0.05). FIFTEEN OF 24(62.5%) NK/T-CELL LYMPHOMAS SHOWED DNA METHYLATION. HEMATOPOIETIC CELL LINES WITH A METHYLATED GENE WERE RESISTANT TO APOPTOSIS. TREATMENT OF THE CELLS WITH A DEMETHYLATING AGENT RESTORED APOPTOTIC CELL DEATH IN ONE B-CELL LYMPHOMA CELL LINE WITH DNA METHYLATION. OUR RESULTS SUGGESTED THAT SUPPRESSION OF DAP-KINASE EXPRESSION BY DNA METHYLATION MIGHT PLAY A ROLE IN THE DEVELOPMENT OF B-CELL MALIGNANCIES. 2001 2 5564 84 ROLE OF HYPERMETHYLATION OF DAP-KINASE CPG ISLAND IN THE DEVELOPMENT OF THYROID LYMPHOMA. DEATH-ASSOCIATED PROTEIN-KINASE (DAP-KINASE) IS A SERINE/THREONINE KINASE WITH A DEATH DOMAIN THAT IS INVOLVED IN APOPTOSIS INDUCED BY INTERFERON-GAMMA, TNF-ALPHA, AND FAS LIGAND. EPIGENETIC DOWN-REGULATION OF DAP-KINASE GENE EXPRESSION BY HYPERMETHYLATION OF ITS PROMOTER REGION WAS REPORTED IN B-CELL MALIGNANCIES. PREVIOUS PATHOEPIDEMIOLOGIC STUDIES INDICATED THAT THYROID LYMPHOMA (TL) EVOLVES AMONG ACTIVE LYMPHOID CELLS IN CHRONIC LYMPHOCYTIC THYROIDITIS (CLTH). WITH USE OF METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION, THE METHYLATION STATUS OF DAP-KINASE CPG ISLAND WAS EXAMINED IN THYROID LESIONS OF 19 CASES WITH TL AND 9 WITH CLTH. THE FREQUENCY OF METHYLATION WAS HIGHER IN TL CASES (16 OF 19, 84.2%) THAN IN CLTH CASES (2 OF 9, 22.2%) (P < 0.01). DNA EXTRACTED FROM PERIPHERAL BLOOD LEUKOCYTES FROM TL AND CLTH CASES NEVER SHOWED METHYLATION, INDICATING THAT THE METHYLATION OCCURRED SOMATICALLY IN THE LESIONAL LYMPHOCYTES IN THYROID. THESE FINDINGS SUGGESTED THAT METHYLATION OF THE DAP-KINASE PROMOTER REGION MIGHT BE INVOLVED IN THE DEVELOPMENT OF TL FROM CLTH. 2000 3 1662 28 DOWNREGULATION OF DEATH-ASSOCIATED PROTEIN KINASE 1 (DAPK1) IN CHRONIC LYMPHOCYTIC LEUKEMIA. THE HERITABILITY OF B CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS RELATIVELY HIGH; HOWEVER, NO PREDISPOSING MUTATION HAS BEEN CONVINCINGLY IDENTIFIED. WE SHOW THAT LOSS OR REDUCED EXPRESSION OF DEATH-ASSOCIATED PROTEIN KINASE 1 (DAPK1) UNDERLIES CASES OF HERITABLE PREDISPOSITION TO CLL AND THE MAJORITY OF SPORADIC CLL. EPIGENETIC SILENCING OF DAPK1 BY PROMOTER METHYLATION OCCURS IN ALMOST ALL SPORADIC CLL CASES. FURTHERMORE, WE DEFINED A DISEASE HAPLOTYPE, WHICH SEGREGATES WITH THE CLL PHENOTYPE IN A LARGE FAMILY. DAPK1 EXPRESSION OF THE CLL ALLELE IS DOWNREGULATED BY 75% IN GERMLINE CELLS DUE TO INCREASED HOXB7 BINDING. IN THE BLOOD CELLS FROM AFFECTED FAMILY MEMBERS, PROMOTER METHYLATION RESULTS IN ADDITIONAL LOSS OF DAPK1 EXPRESSION. THUS, REDUCED EXPRESSION OF DAPK1 CAN RESULT FROM GERMLINE PREDISPOSITION, AS WELL AS EPIGENETIC OR SOMATIC EVENTS CAUSING OR CONTRIBUTING TO THE CLL PHENOTYPE. 2007 4 1424 31 DIFFERENTIAL DNA METHYLATION OF GENE PROMOTERS IN SMALL B-CELL LYMPHOMAS. IMPROVED CARE OF PATIENTS WITH SMALL B-CELL LYMPHOMAS (SBCLS) IS LIKELY TO RESULT FROM THE ONGOING DISCOVERY OF MOLECULAR MARKERS THAT BETTER DEFINE THESE MALIGNANT NEOPLASMS. WE IDENTIFIED MULTIPLE GENE LOCI WHOSE DNA METHYLATION PATTERNS DIFFERED BETWEEN 3 TYPES OF SBCL: B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA, MANTLE CELL LYMPHOMA, AND GRADES I AND II FOLLICULAR LYMPHOMA. THIS ANALYSIS WAS PERFORMED USING AN OLIGONUCLEOTIDE MICROARRAY THAT ALLOWED DETERMINATION OF THE DNA METHYLATION STATUS OF 156 LOCI IN 38 GENES. COMBINED BISULFITE RESTRICTION ANALYSIS AND METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION WERE USED TO VALIDATE THE DIFFERENTIAL METHYLATION OF 6 OF THESE GENES. BY USING NON-HODGKIN LYMPHOMA CELL LINES AS MODELS, THESE GENES WERE EXAMINED FURTHER FOR METHYLATION AND GENE EXPRESSION RELATIONSHIPS. THIS STUDY ILLUSTRATES NONRANDOM EPIGENETIC ALTERATIONS IN SBCLS THAT SEEM TO PREFERENTIALLY INVOLVE LYMPHOMAS OF GERMINAL CENTER DERIVATION. 2005 5 3062 35 GENOME-WIDE DNA METHYLATION ANALYSIS REVEALS NOVEL EPIGENETIC CHANGES IN CHRONIC LYMPHOCYTIC LEUKEMIA. WE CONDUCTED A GENOME-WIDE DNA METHYLATION ANALYSIS IN CD19 (+) B-CELLS FROM CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) PATIENTS AND NORMAL CONTROL SAMPLES USING REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS). THE METHYLATION STATUS OF 1.8-2.3 MILLION CPGS IN THE CLL GENOME WAS DETERMINED; ABOUT 45% OF THESE CPGS WERE LOCATED IN MORE THAN 23,000 CPG ISLANDS (CGIS). WHILE GLOBAL CPG METHYLATION WAS SIMILAR BETWEEN CLL AND NORMAL B-CELLS, 1764 GENE PROMOTERS WERE IDENTIFIED AS BEING DIFFERENTIALLY METHYLATED IN AT LEAST ONE CLL SAMPLE WHEN COMPARED WITH NORMAL B-CELL SAMPLES. NINETEEN PERCENT OF THE DIFFERENTIALLY METHYLATED GENES WERE INVOLVED IN TRANSCRIPTIONAL REGULATION. ABERRANT HYPERMETHYLATION WAS FOUND IN ALL HOX GENE CLUSTERS AND A SIGNIFICANT NUMBER OF WNT SIGNALING PATHWAY GENES. HYPOMETHYLATION OCCURRED MORE FREQUENTLY IN THE GENE BODY INCLUDING INTRONS, EXONS, AND 3'-UTRS IN CLL. THE NFATC1 P2 PROMOTER AND FIRST INTRON WAS FOUND TO BE HYPOMETHYLATED AND CORRELATED WITH UPREGULATION OF BOTH NFATC1 RNA AND PROTEIN EXPRESSION LEVELS IN CLL SUGGESTING THAT AN EPIGENETIC MECHANISM IS INVOLVED IN THE CONSTITUTIVE ACTIVATION OF NFAT ACTIVITY IN CLL CELLS. THIS COMPREHENSIVE DNA METHYLATION ANALYSIS WILL FURTHER OUR UNDERSTANDING OF THE EPIGENETIC CONTRIBUTION TO CELLULAR DYSFUNCTION IN CLL. 2012 6 4548 39 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 7 5270 40 PROMOTER DNA METHYLATION FREQUENCY AND CLINICOPATHOLOGICAL ROLE OF MIR-129-2 GENE IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA. OBJECTIVES: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY THE ACCUMULATION OF APPARENTLY MATURE B-TYPE LYMPHOCYTES IN THE LYMPHOHEMATOPOIETIC ORGANS. METHYLATION IN PROMOTERS OF TUMOR SUPPRESSOR GENES IS ONE OF THE MECHANISMS THAT CAUSES BLOOD MALIGNANCY. IN THIS STUDY, WE EVALUATED THE PROMOTER DNA METHYLATION STATUS OF MIR-129-2 TUMOR SUPPRESSOR GENE AND ITS ASSOCIATION WITH CLINICAL AND LABORATORY PARAMETERS OF PATIENTS WITH CLL. METHODS: WE STUDIED THE PROMOTER DNA METHYLATION FREQUENCY OF THE MIR-129-2 GENE IN 50 PATIENTS WITH CLL AND 50 HEALTHY CONTROLS USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION METHODS. STATISTICAL ANALYSIS WAS PERFORMED USING SPSS-18 SOFTWARE, AND A P-VALUE < 0.050 WAS CONSIDERED STATISTICALLY SIGNIFICANT. RESULTS: THE FREQUENCY OF PROMOTER DNA METHYLATION OF THE MIR-129-2 GENE WAS SIGNIFICANTLY HIGHER IN THE CLL GROUP COMPARED WITH CONTROL GROUP (38.0% VS. 0.0%, P < 0.001; CHI(2) = 23.457). THE PROMOTER DNA METHYLATION FREQUENCY OF MIR-129-2 GENE WAS NOT SIGNIFICANTLY DIFFERENT BETWEEN THE TWO SEXES (P = 0.236). A SIGNIFICANT BUT WEAK CORRELATION WAS SEEN BETWEEN THE METHYLATED STATE OF THE MIR-129-2 GENE AND ORGANOMEGALY (P = 0.019, R = 0.330) AS WELL AS HEMOGLOBIN LEVELS (P = 0.020, R = -0.233). HOWEVER, BINARY LOGISTIC REGRESSION ANALYSIS INDICATED ORGANOMEGALY AS THE ONLY CLINICAL BIOMARKER WITH A STATISTICALLY SIGNIFICANT ASSOCIATION WITH THE HYPERMETHYLATED MIR-129-2 GENE STATE (P = 0.046). CONCLUSIONS: THE HIGH FREQUENCY OF PROMOTER DNA METHYLATION OF THE MIR-129-2 GENE IN THE CLL GROUP COMPARED TO THE CONTROL GROUP, AS WELL AS ITS SIGNIFICANT ASSOCIATION WITH ORGANOMEGALY, SUGGESTS THE IMPORTANCE OF THIS EPIGENETIC BIOMARKER IN THE PATHOGENESIS AND PROGNOSIS OF CLL DISEASE. 2020 8 3444 34 HYPERMETHYLATION OF E-CADHERIN IN LEUKEMIA. E-CADHERIN GENE IS OFTEN TERMED A "METASTASIS SUPPRESSOR" GENE BECAUSE THE E-CADHERIN PROTEIN CAN SUPPRESS TUMOR CELL INVASION AND METASTASIS. INACTIVATION OF THE E-CADHERIN GENE OCCURS IN UNDIFFERENTIATED SOLID TUMORS BY BOTH GENETIC AND EPIGENETIC MECHANISMS; HOWEVER, THE ROLE OF E-CADHERIN IN HEMATOLOGIC MALIGNANCIES IS ONLY NOW BEING RECOGNIZED. E-CADHERIN EXPRESSION IS ESSENTIAL FOR ERYTHROBLAST AND NORMOBLAST MATURATION, YET EXPRESSION IS REDUCED OR ABSENT IN LEUKEMIC BLAST CELLS. THIS STUDY EXAMINED THE MESSENGER RNA (MRNA) AND PROTEIN EXPRESSION OF THE E-CADHERIN GENE IN BONE MARROW AND BLOOD SAMPLES FROM NORMAL DONORS AND PATIENTS WITH LEUKEMIA. WE FOUND THAT ALL NORMAL DONOR SAMPLES EXPRESSED E-CADHERIN MRNA, WHEREAS BOTH SAMPLES OF ACUTE MYELOGENOUS LEUKEMIA AND CHRONIC LYMPHOCYTIC LEUKEMIA HAD A SIGNIFICANT REDUCTION OR ABSENCE OF EXPRESSION. HOWEVER, NORMAL BLAST COUNTERPARTS EXPRESSED ONLY A LOW LEVEL OF E-CADHERIN SURFACE PROTEIN. SODIUM BISULPHITE GENOMIC SEQUENCING WAS USED TO FULLY CHARACTERIZE THE METHYLATION PATTERNS OF THE CPG ISLAND ASSOCIATED WITH THE E-CADHERIN GENE PROMOTER IN THOSE SAMPLES WITH MATCHED DNA. ALL OF THE NORMAL CONTROL SAMPLES WERE ESSENTIALLY UNMETHYLATED; HOWEVER, 14 OF 18 (78%) OF THE LEUKEMIA SAMPLES HAD ABNORMAL HYPERMETHYLATION OF THE E-CADHERIN CPG ISLAND. IN FACT BOTH ALLELES OF THE E-CADHERIN GENE WERE OFTEN HYPERMETHYLATED. WE CONCLUDE THE E-CADHERIN GENE IS A COMMON TARGET FOR HYPERMETHYLATION IN HEMATOLOGIC MALIGNANCIES. 2000 9 2262 32 EPIGENETIC PROFILING IN CHRONIC LYMPHOCYTIC LEUKEMIA REVEALS NOVEL METHYLATION TARGETS. CPG ISLAND METHYLATION IS AN EPIGENETIC ALTERATION THAT CONTRIBUTES TO TUMORIGENESIS BY TRANSCRIPTIONAL INACTIVATION OF GENES. LITTLE IS KNOWN ABOUT THE OVERALL LEVELS OF CPG ISLAND METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). TO PROVIDE A BASELINE ESTIMATE OF GLOBAL ABERRANT METHYLATION AND IDENTIFY TARGET SEQUENCES FOR ADDITIONAL INVESTIGATION, WE PERFORMED RESTRICTION LANDMARK GENOMIC SCANNING ON 10 CLL SAMPLES. TWO METHYLATION-SENSITIVE LANDMARK ENZYMES WERE USED (NOTI AND ASCI), ALLOWING ASSESSMENT OF OVER 3000 CPG ISLANDS IN EACH SAMPLE. TUMOR-DERIVED RESTRICTION LANDMARK GENOMIC SCANNING PROFILES WERE COMPARED WITH PROFILES FROM CD19-SELECTED B CELLS FROM NORMAL VOLUNTEERS AND MATCHED NORMAL NEUTROPHILS FROM 4 CLL PATIENTS. WE FOUND 2.5-8.1% (MEAN 4.8%) OF THE CPG ISLANDS IN CLL SAMPLES WERE ABERRANTLY METHYLATED COMPARED WITH CONTROLS, AND THE METHYLATION EVENTS HAD A NONRANDOM DISTRIBUTION (P < 0.0001). FURTHERMORE, WE IDENTIFIED 193 ABERRANTLY METHYLATED SEQUENCES, OF WHICH 93% HAVE CPG ISLAND CHARACTERISTICS AND 90% HAVE HOMOLOGY TO GENES OR EXPRESSED SEQUENCES. ONE SUCH GENE, THE G PROTEIN-COUPLED METABOTROPIC GLUTAMATE RECEPTOR 7 (GRM7), POSSIBLY INHIBITS CYCLIC AMP SIGNALING IN THE INDUCTION OF APOPTOSIS. BISULFITE SEQUENCING OF GRM7 CONFIRMED EXTENSIVE CPG ISLAND METHYLATION, AND TREATMENT WITH 5-AZA-2'-DEOXYCYTIDINE (DECITABINE) RESULTED IN UP-REGULATED EXPRESSION OF SEVERAL GENES IN VITRO WITH CONCURRENT CELLULAR DEPLETION OF DNMT1 PROTEIN. OUR DUAL-ENZYME GLOBAL METHYLATION STUDY SHOWS THAT CLL IS CHARACTERIZED BY WIDESPREAD NONRANDOM CPG ISLAND METHYLATION SIMILAR TO OTHER TUMORS AND PROVIDES A PANEL OF NOVEL METHYLATION TARGETS THAT CAN BE USED IN LARGER STUDIES DESIGNED TO ASSESS IMPACT ON DISEASE PROGRESSION AND SURVIVAL. 2004 10 156 42 ABERRANT METHYLATION OF THE DEATH-ASSOCIATED PROTEIN KINASE 1 (DAPK1) CPG ISLAND IN CHRONIC MYELOID LEUKEMIA. THE DEATH-ASSOCIATED PROTEIN KINASE 1 (DAPK1) GENE IS A CANDIDATE TUMOR SUPPRESSOR (TSG) AND THE ABNORMAL METHYLATION OF DAPK1 GENE HAS BEEN FOUND IN MANY CARCINOMAS. THE EPIGENETIC CHANGES OF TSGS ARE NOW RECOGNIZED AS A MECHANISM CONTRIBUTING TO THE DEVELOPMENT OF CHRONIC MYELOID LEUKEMIA (CML). TO CLARIFY THE ROLE OF DAPK1 IN CML, WE EXAMINED THE METHYLATION STATUS OF DAPK1 IN 49 PATIENTS WITH CML USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. THE ABERRANT METHYLATION OF THE DAPK1 GENE WAS FOUND IN 25 OF 49 (51.0%) CML CASES, NOT IN ALL CONTROLS. NO CORRELATION WAS FOUND BETWEEN DAPK1 GENE METHYLATION AND THE AGE, HEMATOLOGIC PARAMETERS, CHROMOSOMAL ABNORMALITIES, THE TYPES AND LEVELS OF BCR/ABL TRANSCRIPTS OF CML PATIENTS. HOWEVER, CORRELATION COULD BE OBSERVED BETWEEN THE SEX AND THE STATUS OF DAPK1 METHYLATION IN CML PATIENTS (R = 0.374, P = 0.008). FURTHERMORE, THERE WAS A SIGNIFICANT CORRELATION BETWEEN DAPK1 METHYLATION AND THE STAGES OF CML (R = 0.354, P = 0.013). THE CML PATIENTS IN ACCELERATED PHASE (AP) AND BLAST CRISIS (BC) HAD HIGHER FREQUENCY OF DAPK1 METHYLATION THAN THOSE IN CHRONIC PHASE (CP) (75.0% VS. 34.5%) (CHI(2) = 7.776, P = 0.005). IN ONE PATIENT, THE STATUS OF DAPK1 METHYLATION BECAME POSITIVE ON THE TRANSITION FROM CP TO AP AND BC. THESE RESULTS SUGGESTED THAT DAPK1 PROMOTER METHYLATION MIGHT PLAY A SIGNIFICANT ROLE IN THE PROGRESSION OF CML. 2009 11 1211 38 CPG ISLAND METHYLATION AND EXPRESSION OF THE SECRETED FRIZZLED-RELATED PROTEIN GENE FAMILY IN CHRONIC LYMPHOCYTIC LEUKEMIA. B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY A CLONAL ACCUMULATION OF MATURE NEOPLASTIC B CELLS INDICATING DISRUPTION OF APOPTOSIS. RESTRICTION LANDMARK GENOME SCANNING WAS DONE TO IDENTIFY NOVEL TARGET GENES SILENCED BY CPG ISLAND METHYLATION IN CLL. SECRETED FRIZZLED-RELATED PROTEIN 4 (SFRP4), A NEGATIVE REGULATOR OF THE WNT SIGNALING PATHWAY, WAS FOUND TO BE FREQUENTLY METHYLATED IN CLL SAMPLES. WNT SIGNALING HAS BEEN SHOWN TO CONTROL NORMAL APOPTOTIC BEHAVIOR AND IS REQUIRED FOR NORMAL B-CELL DEVELOPMENT WHEREAS ABERRANT ACTIVATION OF THIS PATHWAY HAS BEEN OBSERVED IN CLL. WE SHOW ABERRANT DNA METHYLATION AND SILENCING OF SFRP4, AS WELL AS OF ADDITIONAL SFRP FAMILY MEMBERS, IN PRIMARY CLL SAMPLES. INDUCTION OF THEIR EXPRESSION IN A DOSE-DEPENDENT MANNER FOLLOWING TREATMENT WITH A DEMETHYLATING AGENT, 5-AZA-2'-DEOXYCYTIDINE, WAS SHOWN. OF THE FIVE SFRP FAMILY MEMBERS STUDIED IN DETAIL, SFRP1 WAS HYPERMETHYLATED AND DOWN-REGULATED IN ALL CLL PATIENT SAMPLES STUDIED, SUGGESTING THAT THIS EPIGENETIC EVENT IS A CRITICAL STEP DURING LEUKEMOGENESIS. OUR RESULTS SUGGEST THAT SILENCING OF SFRPS BY CPG ISLAND METHYLATION IS ONE POSSIBLE MECHANISM CONTRIBUTING TO ABERRANT ACTIVATION OF WNT SIGNALING PATHWAY IN CLL. 2006 12 2090 26 EPIGENETIC DYSREGULATION OF THE WNT SIGNALLING PATHWAY IN CHRONIC LYMPHOCYTIC LEUKAEMIA. BACKGROUND: WNT SIGNALLING HAS RECENTLY BEEN IMPLICATED IN THE PATHOGENESIS OF CANCER. METHODS: THIS STUDY INVESTIGATED THE ACTIVITY OF WNT SIGNALLING IN PERIPHERAL BLOOD CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) LYMPHOCYTES, AND THE METHYLATION STATUS OF SEVEN SOLUBLE WNT ANTAGONIST GENES, INCLUDING WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 AND SFRP5, BY USING METHYLATION-SPECIFIC PCR IN THE PERIPHERAL BLOOD CLL LYMPHOCYTES AND BONE MARROW SAMPLES OF PATIENTS WITH CLL AT DIAGNOSIS. RESULTS: IN THE PERIPHERAL BLOOD CLL LYMPHOCYTES, CONSTITUTIVE ACTIVATION OF WNT SIGNALLING WAS DETECTED, ASSOCIATED WITH HYPERMETHYLATION OF THE SOLUBLE WNT INHIBITOR GENES. IN THE DIAGNOSTIC CLL MARROW SAMPLES, METHYLATION OF THE SEVEN GENES WAS DETECTED IN UP TO 36.4% OF SAMPLES. MOREOVER, 23 (52.3%) PATIENTS HAD METHYLATION OF AT LEAST ONE OF THE SEVEN GENES, OF WHOM 14 (60.8%) HAD METHYLATION OF TWO OR MORE WNT INHIBITOR GENES. APART FROM AN ASSOCIATION OF ADVANCED AGE WITH DKK3 METHYLATION, THERE WAS NO ASSOCIATION OF GENE HYPERMETHYLATION WITH EITHER CLINICAL CHARACTERISTICS (INCLUDING AGE, GENDER, LYMPHOCYTE COUNT AT DIAGNOSIS, RAI STAGE AND POOR-RISK KARYOTYPE) OR SURVIVAL. CONCLUSION: WNT SIGNALLING IS CONSTITUTIVELY ACTIVATED IN CLL B LYMPHOCYTES IN ASSOCIATION WITH METHYLATION OF MULTIPLE SOLUBLE WNT ANTAGONIST GENES. METHYLATION OF THESE SOLUBLE WNT ANTAGONIST GENES, OCCASIONALLY MULTIPLE GENES, IN PRIMARY CLL MARROW SAMPLES SUGGESTS AN IMPORTANT ROLE IN CLL PATHOGENESIS. MOREOVER, THIS STUDY UNDERSCORED THE IMPORTANCE OF STUDYING METHYLATION OF A PANEL OF, BUT NOT INDIVIDUAL, GENES REGULATING A CELLULAR PATHWAY. 2008 13 4243 39 METHYLATION STATUS OF CEBPA GENE PROMOTER IN CHRONIC MYELOID LEUKEMIA. CCAAT/ENHANCER BINDING PROTEIN ALPHA IS ONE OF THE CRUCIAL TRANSCRIPTION FACTORS FOR MYELOID CELL DEVELOPMENT THAT HAS BEEN FOUND TO BE INVOLVED IN HEMATOPOIETIC DIFFERENTIATION AND LEUKEMIOGENESIS. RECENTLY, EPIGENETIC REGULATION OF CEBPA EXPRESSION THROUGH DNA METHYLATION HAS BEEN DEMONSTRATED IN LEUKEMIA. THE AIM OF THIS STUDY WAS TO INVESTIGATE THE METHYLATION STATUS OF CEBPA GENE IN CHRONIC MYELOID LEUKEMIA (CML) PATIENTS. THE METHYLATION STATUS OF CEBPA PROMOTER WAS STUDIED IN 100 PATIENTS WITH CML AND 98 NORMAL HEALTHY INDIVIDUALS FROM HYDERABAD, INDIA, USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. THE ABERRANT METHYLATION OF CEBPA GENE PROMOTER WAS FOUND IN 32 OF THE 100 CML CASES. A HIGHLY SIGNIFICANT ASSOCIATION WAS FOUND BETWEEN THE FREQUENCY OF CEBPA GENE PROMOTER HYPERMETHYLATION AND THE CML STAGES (P = 0.017), BUT ASSOCIATION WITH RESPECT TO AGE AND GENDER OF THE PATIENT WAS NOT FOUND. THE RESULTS SUGGEST THAT ABERRANT METHYLATION IN THE CPG ISLAND OF THE PROMOTER REGION OF THIS GENE MIGHT BE A COMMON EVENT IN CML, AND SYSTEMIC EXPRESSION STUDIES WILL BE NEEDED TO UNFOLD THE ROLE OF CEBPA PROMOTER METHYLATION IN THE DEVELOPMENT, PROGRESSION, AND PROGNOSIS OF CML. 2014 14 5275 49 PROMOTER METHYLATION OF THE BONE MORPHOGENETIC PROTEIN-6 GENE IN ASSOCIATION WITH ADULT T-CELL LEUKEMIA. BONE MORPHOGENETIC PROTEINS (BMP), BELONGING TO THE TRANSFORMING GROWTH FACTOR-BETA SUPERFAMILY, ARE MULTIFUNCTIONAL REGULATORS OF CELL PROLIFERATION, DIFFERENTIATION AND APOPTOSIS IN VARIOUS TYPES OF MALIGNANT CELLS. IN THIS STUDY, WE INVESTIGATED BMP-6 PROMOTER METHYLATION IN PATIENTS WITH VARIOUS TYPES OF LEUKEMIAS. THE BMP-6 METHYLATION WAS FOUND PREFERENTIALLY IN ADULT T-CELL LEUKEMIA (ATL) (49 OF 60, 82%) COMPARED WITH OTHER TYPES OF LEUKEMIAS STUDIED INCLUDING ACUTE MYELOID LEUKEMIA (3 OF 67, 5%), ACUTE LYMPHOBLASTIC LEUKEMIA (6 OF 38, 16%) AND CHRONIC LYMPHOCYTIC LEUKEMIA (1 OF 21, 5%). AMONG SUBTYPES OF ATL, THE BMP-6 GENE WAS MORE FREQUENTLY METHYLATED IN AGGRESSIVE ATL FORMS OF ACUTE (96%) AND LYMPHOMA (94%) TYPES THAN LESS MALIGNANT CHRONIC ATL (44%) AND SMOLDERING ATL (20%). WE ALSO ANALYZED THE METHYLATION STATUS OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM HEALTHY DONORS AND NONMALIGNANT LYMPH NODES WITH REACTIVE LYMPHADENOPATHY, NONE OF WHICH SHOWED DETECTABLE BMP-6 METHYLATION IN THIS STUDY. THE BMP-6 METHYALTION WAS CORRELATED WITH DECREASED MRNA TRANSCRIPT AND PROTEIN EXPRESSION. EXPRESSION OF BMP-6 WAS RESTORED BY THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE, SUGGESTING THAT METHYLATION WAS ASSOCIATED WITH THE TRANSCRIPTIONAL SILENCING. SERIAL ANALYSIS DEMONSTRATED AN INCREASING METHYLATION OF CPG SITES IN THE BMP-6 PROMOTER AND THE RESULTANT SUPPRESSION OF BMP-6 EXPRESSION AS ATL PROGRESSED. THESE FINDINGS SUGGESTED THAT BMP-6 PROMOTER METHYLATION IS LIKELY TO BE A COMMON EPIGENETIC EVENT AT LATER STAGES OF ATL AND THAT THE METHYLATION PROFILES MAY BE USEFUL FOR THE STAGING OF ATL AS WELL AS FOR EVALUATION OF THE INDIVIDUAL RISK OF DEVELOPING THE DISEASE. 2008 15 3588 34 IMPACT OF TP53 GENE PROMOTER METHYLATION ON CHRONIC LYMPHOCYTIC LEUKEMIA PATHOGENESIS AND PROGRESSION. BACKGROUND: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A MALIGNANT LYMPHOID DISORDER THAT RESULTS FROM THE OVERGROWTH OF MATURE-LOOKING LYMPHOID CELLS IN THE BLOOD AND LYMPHATIC TISSUE. VARIOUS CLINICAL PRESENTATIONS HAVE BEEN ATTRIBUTED TO THE DISEASE AS A RESULT OF THE DIFFERENT UNDERLYING GENETIC AND EPIGENETIC ALTERATIONS. THE CURRENT STUDY HAS BEEN INITIATED TO STUDY THE ROLE OF AN EPIGENETIC ALTERATION AFFECTING THE PROMOTER OF THE TP53GENE ON CLL PATHOGENESIS AND PROGRESSION. METHODS: THE CURRENT STUDY INVOLVED 54 NEWLY DIAGNOSED PATIENTS PRESENTING WITH CLL AS WELL AS 30 NORMAL INDIVIDUALS AS CONTROLS. AFTER OBTAINING VERBAL CONSENT, DATA COLLECTION WAS DONE AND THE BLOOD COLLECTED FROM ALL ENROLLED INDIVIDUALS FOR HEMATOLOGICAL INVESTIGATIONS AS WELL AS FOR MOLECULAR CATEGORIZATION OF TP53 METHYLATION STATUS. METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MS-PCR) TECHNIQUE WAS USED TO DEFINE THE METHYLATION STATUS OF THE TP53 GENE PROMOTER THAT ENCOMPASSES DNA EXTRACTION, BISULFITE CONVERSION, CONVENTIONAL PCR AMPLIFICATION, RUNNING ON AGAROSE GEL AND DOCUMENTATION. FINALLY, STATISTICAL ANALYSIS WAS DONE TO ASSESS ANY CORRELATION OF THE TP53 EPIGENETIC ALTERATION TO THE DISEASE ETIOLOGY AND THE PROGRESSION. RESULTS: IN THE CURRENT STUDY, ALL CONTROLS AND 42 OF 54 PATIENTS SHOW UNMETHYLATED TP53 GENE PROMOTER; ON THE OTHER HAND, THE METHYLATED PROMOTER WAS DETECTED AMONG 12 PATIENTS WITH A P-VALUE OF 0.001. TP53 GENE PROMOTER METHYLATION SIGNIFICANTLY LINKED TO REDUCED PLATELET COUNT (P-VALUE OF 0.047) AND ADVANCED STAGE AT PRESENTATION (P-VALUE OF 0.076). NO SIGNIFICANT DIFFERENCES WERE SEEN AMONG BOTH METHYLATED AND UNMETHYLATED TP53 PROMOTERS IN RELATION TO THE AGE OF THE AFFECTED INDIVIDUALS, TOTAL WHITE BLOOD CELL COUNTS AND HEMOGLOBIN LEVEL OF THE AFFECTED INDIVIDUALS. CONCLUSION: THE CURRENT STUDY REVEALED A SIGNIFICANT CORRELATION OF TP53 GENE PROMOTER METHYLATION TO CHRONIC LYMPHOCYTIC LEUKEMIA PATHOGENESIS AND LOWER PLATELET COUNTS. 2019 16 206 37 ACTIVATION OF NOTCH AND MYC SIGNALING VIA B-CELL-RESTRICTED DEPLETION OF DNMT3A GENERATES A CONSISTENT MURINE MODEL OF CHRONIC LYMPHOCYTIC LEUKEMIA. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY DISORDERED DNA METHYLATION, SUGGESTING THESE EPIGENETIC CHANGES MIGHT PLAY A CRITICAL ROLE IN DISEASE ONSET AND PROGRESSION. THE METHYLTRANSFERASE DNMT3A IS A KEY REGULATOR OF DNA METHYLATION. ALTHOUGH DNMT3A SOMATIC MUTATIONS IN CLL ARE RARE, WE FOUND THAT LOW DNMT3A EXPRESSION IS ASSOCIATED WITH MORE AGGRESSIVE DISEASE. A CONDITIONAL KNOCKOUT MOUSE MODEL SHOWED THAT HOMOZYGOUS DEPLETION OF DNMT3A FROM B CELLS RESULTS IN THE DEVELOPMENT OF CLL WITH 100% PENETRANCE AT A MEDIAN AGE OF ONSET OF 5.3 MONTHS, AND HETEROZYGOUS DNMT3A DEPLETION YIELDS A DISEASE PENETRANCE OF 89% WITH A MEDIAN ONSET AT 18.5 MONTHS, CONFIRMING ITS ROLE AS A HAPLOINSUFFICIENT TUMOR SUPPRESSOR. B1A CELLS WERE CONFIRMED AS THE CELL OF ORIGIN OF DISEASE IN THIS MODEL, AND DNMT3A DEPLETION RESULTED IN FOCAL HYPOMETHYLATION AND ACTIVATION OF NOTCH AND MYC SIGNALING. AMPLIFICATION OF CHROMOSOME 15 CONTAINING THE MYC GENE WAS DETECTED IN ALL CLL MICE TESTED, AND INFILTRATION OF HIGH-MYC-EXPRESSING CLL CELLS IN THE SPLEEN WAS OBSERVED. NOTABLY, HYPERACTIVATION OF NOTCH AND MYC SIGNALING WAS EXCLUSIVELY OBSERVED IN THE DNMT3A CLL MICE, BUT NOT IN THREE OTHER CLL MOUSE MODELS TESTED (SF3B1-ATM, IKZF3, AND MDR), AND DNMT3A-DEPLETED CLL WERE SENSITIVE TO PHARMACOLOGIC INHIBITION OF NOTCH SIGNALING IN VITRO AND IN VIVO. CONSISTENT WITH THESE FINDINGS, HUMAN CLL SAMPLES WITH LOWER DNMT3A EXPRESSION WERE MORE SENSITIVE TO NOTCH INHIBITION THAN THOSE WITH HIGHER DNMT3A EXPRESSION. ALTOGETHER, THESE RESULTS SUGGEST THAT DNMT3A DEPLETION INDUCES CLL THAT IS HIGHLY DEPENDENT ON ACTIVATION OF NOTCH AND MYC SIGNALING. SIGNIFICANCE: LOSS OF DNMT3A EXPRESSION IS A DRIVING EVENT IN CLL AND IS ASSOCIATED WITH AGGRESSIVE DISEASE, ACTIVATION OF NOTCH AND MYC SIGNALING, AND ENHANCED SENSITIVITY TO NOTCH INHIBITION. 2021 17 2133 32 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 18 2847 25 FREQUENT P15 PROMOTER METHYLATION IN TUMOR AND PERIPHERAL BLOOD FROM HEPATOCELLULAR CARCINOMA PATIENTS. WE PROSPECTIVELY ANALYZED P15 METHYLATION PATTERNS IN 25 SURGICALLY RESECTED TUMORS AND 130 PLASMA, SERUM, AND BUFFY COAT SAMPLES FROM HEPATOCELLULAR CARCINOMA (HCC) PATIENTS, CONTROLS WITH CHRONIC HEPATITIS/CIRRHOSIS, AND HEALTHY SUBJECTS. USING METHYLATION-SPECIFIC PCR, WE DEMONSTRATED FOR THE FIRST TIME P15 PROMOTER METHYLATION IN 64% OF TUMORS AND 25% (4 OF 16) OF PATIENTS' PLASMA AND SERUM SAMPLES. CONCURRENT P15 AND P16 METHYLATION WAS SHOWN IN 48% OF TUMORS, AND P15/P16 METHYLATION WAS DETECTED IN THE PLASMA/SERUM OF 92% (11 OF 12) OF PATIENTS. OF NOTE, 75% OF 12 PATIENTS WITH CONCURRENT TUMOR METHYLATION DEVELOPED CLINICAL METASTASIS/RECURRENCE (P = 0.027). IN BUFFY COAT SAMPLES, P15 METHYLATION WAS DETECTED IN ALL EIGHT PATIENTS WITH TUMOR P15 METHYLATION, SUGGESTING THE PRESENCE OF CIRCULATING TUMOR CELLS. NONE OF THE CONTROL SAMPLES WERE METHYLATION POSITIVE. OUR DATA UNDERSCORE THE IMPORTANT ROLE(S) OF P15 AND P16 METHYLATION IN HEPATOCARCINOGENESIS AND TUMOR PROGRESSION. AMONG 92% (23 OF 25) OF PATIENTS WITH TUMOR P15/P16 METHYLATION, CIRCULATING TUMOR DNA AND HCC CELLS WERE DETECTED IN THE PERIPHERAL BLOOD OF 87% (20 OF 23) OF PATIENTS. THE COMBINATION OF THESE EPIGENETIC MARKERS MAY PROVE VALUABLE FOR NONINVASIVE HCC DIAGNOSIS AND DISEASE MONITORING. 2000 19 3461 38 HYPOMETHYLATION-MEDIATED H19 OVEREXPRESSION INCREASES THE RISK OF DISEASE EVOLUTION THROUGH THE ASSOCIATION WITH BCR-ABL TRANSCRIPT IN CHRONIC MYELOID LEUKEMIA. PREVIOUS STUDY HAS REVEALED THAT H19 EXPRESSION IS REQUIRED FOR EFFICIENT TUMOR GROWTH INDUCED BY BCR-ABL IN CHRONIC MYELOID LEUKEMIA (CML). HEREIN, WE FURTHER DETERMINED H19 EXPRESSION AND ITS CLINICAL IMPLICATION IN PATIENTS WITH CML. H19 EXPRESSION AND METHYLATION WERE DETECTED BY REAL-TIME QUANTITATIVE PCR AND REAL-TIME QUANTITATIVE METHYLATION-SPECIFIC PCR, AND THEN CLINICAL IMPLICATION OF H19 EXPRESSION WAS FURTHER ANALYZED. H19 EXPRESSION WAS SIGNIFICANTLY UP-REGULATED IN CML PATIENTS (P < 0.001). H19 EXPRESSION WITH AN AREA UNDER RECEIVER OPERATING CHARACTERISTIC CURVE VALUE OF 0.824 MIGHT SERVE AS A PROMISING BIOMARKER IN DISTINGUISHING CML PATIENTS FROM CONTROLS. THE PATIENTS WITH HIGH H19 EXPRESSION HAD A TENDENCY OF HIGHER WHITE BLOOD CELLS AND BCR-ABL TRANSCRIPT THAN THOSE WITH LOW H19 EXPRESSION. H19 OVEREXPRESSION OCCURRED WITH THE HIGHER FREQUENCY IN BLAST CRISIS STAGE (11/11, 100%), LOWER IN ACCELERATED PHASE (3/5, 60%), AND CHRONIC PHASE (42/62, 66%) STAGES. MOREOVER, PAIRED PATIENTS DURING DISEASE PROGRESSION WITH INCREASED BCR-ABL TRANSCRIPT ALSO SHOWED A SIGNIFICANT UPREGULATION OF H19 EXPRESSION. MEANWHILE, H19 EXPRESSION WAS DECREASED IN FOLLOW-UP PATIENTS WHO ACHIEVED COMPLETE MOLECULAR REMISSION AFTER TYROSINE KINASE INHIBITORS-BASED THERAPY. EPIGENETIC STUDIES SHOWED THAT H19 DIFFERENTIALLY METHYLATED REGION/IMPRINTING CONTROL REGION (DMR/ICR) WAS HYPOMETHYLATED AND ASSOCIATED WITH H19 EXPRESSION IN CML PATIENTS. MOREOVER, DEMETHYLATION OF H19 DMR/ICR REACTIVATED H19 EXPRESSION IN K562 CELLS. COLLECTIVELY, H19 OVEREXPRESSION, A FREQUENT EVENT IN CML, WAS ASSOCIATED WITH HIGHER BCR-ABL TRANSCRIPT INVOLVING IN DISEASE PROGRESSION. MOREOVER, H19 DMR/ICR HYPOMETHYLATION IN CML MAY BE ONE OF THE MECHANISMS MEDIATING H19 OVEREXPRESSION. 2018 20 59 35 A GENOME-WIDE SCREEN IDENTIFIES FREQUENTLY METHYLATED GENES IN HAEMATOLOGICAL AND EPITHELIAL CANCERS. BACKGROUND: GENETIC AS WELL AS EPIGENETIC ALTERATIONS ARE A HALLMARK OF BOTH EPITHELIAL AND HAEMATOLOGICAL MALIGNANCIES. HIGH THROUGHPUT SCREENS ARE REQUIRED TO IDENTIFY EPIGENETIC MARKERS THAT CAN BE USEFUL FOR DIAGNOSTIC AND PROGNOSTIC PURPOSES ACROSS MALIGNANCIES. RESULTS: HERE WE REPORT FOR THE FIRST TIME THE USE OF THE MIRA ASSAY (METHYLATED CPG ISLAND RECOVERY ASSAY) IN COMBINATION WITH GENOME-WIDE CPG ISLAND ARRAYS TO IDENTIFY EPIGENETIC MOLECULAR MARKERS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) ON A GENOME-WIDE SCALE. WE IDENTIFIED 30 GENES DEMONSTRATING METHYLATION FREQUENCIES OF > OR =25% IN CHILDHOOD ALL, NINE GENES SHOWED SIGNIFICANTLY DIFFERENT METHYLATION FREQUENCIES IN B VS T-ALL. FOR MAJORITY OF THE GENES EXPRESSION COULD BE RESTORED IN METHYLATED LEUKEMIA LINES AFTER TREATMENT WITH 5-AZADC. FORTY-FOUR PERCENT OF THE GENES REPRESENT TARGETS OF THE POLYCOMB COMPLEX. IN CHRONIC MYELOID LEUKEMIA (CML) TWO OF THE GENES, (TFAP2A AND EBF2), DEMONSTRATED INCREASED METHYLATION IN BLAST CRISIS COMPARED TO CHRONIC PHASE (P < 0.05). FURTHERMORE HYPERMETHYLATION OF AN AUTOPHAGY RELATED GENE ATG16L2 WAS ASSOCIATED WITH POORER PROGNOSIS IN TERMS OF MOLECULAR RESPONSE TO IMATINIB TREATMENT. LASTLY WE DEMONSTRATED THAT TEN OF THESE GENES WERE ALSO FREQUENTLY METHYLATED IN COMMON EPITHELIAL CANCERS. CONCLUSION: IN SUMMARY WE HAVE IDENTIFIED A LARGE NUMBER OF GENES SHOWING FREQUENT METHYLATION IN CHILDHOOD ALL, METHYLATION STATUS OF TWO OF THESE GENES IS ASSOCIATED WITH ADVANCED DISEASE IN CML AND METHYLATION STATUS OF ANOTHER GENE IS ASSOCIATED WITH PROGNOSIS. IN ADDITION A SUBSET OF THESE GENES MAY ACT AS EPIGENETIC MARKERS ACROSS HEMATOLOGICAL MALIGNANCIES AS WELL AS COMMON EPITHELIAL CANCERS. 2010