1 1132 128 COMPREHENSIVE DNA METHYLATION ANALYSIS USING A METHYL-CPG-BINDING DOMAIN CAPTURE-BASED METHOD IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS. THE ROLE OF LONG NONCODING RNAS (LNCRNAS) IN CANCER IS COMING TO THE FOREFRONT DUE TO GROWING INTEREST IN UNDERSTANDING THEIR MECHANISTIC FUNCTIONS DURING CANCER DEVELOPMENT AND PROGRESSION. DESPITE THIS, THE GLOBAL EPIGENETIC REGULATION OF LNCRNAS AND REPETITIVE SEQUENCES IN CANCER HAS NOT BEEN WELL INVESTIGATED, PARTICULARLY IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). THIS STUDY FOCUSES ON A UNIQUE APPROACH: THE IMMUNOPRECIPITATION-BASED CAPTURE OF DOUBLE-STRANDED, METHYLATED DNA FRAGMENTS USING METHYL-BINDING DOMAIN (MBD) PROTEINS, FOLLOWED BY NEXT-GENERATION SEQUENCING (MBD-SEQ). CLL PATIENT SAMPLES BELONGING TO TWO PROGNOSTIC SUBGROUPS (5 IGVH MUTATED SAMPLES + 5 IGVH UNMUTATED SAMPLES) WERE USED IN THIS STUDY. ANALYSIS REVEALED 5,800 HYPERMETHYLATED AND 12,570 HYPOMETHYLATED CLL-SPECIFIC DIFFERENTIALLY METHYLATED GENES (CLLDMGS) COMPARED TO NORMAL HEALTHY CONTROLS. IMPORTANTLY, THESE RESULTS IDENTIFIED SEVERAL CLL-SPECIFIC, DIFFERENTIALLY METHYLATED LNCRNAS, REPETITIVE ELEMENTS, AND PROTEIN-CODING GENES WITH POTENTIAL PROGNOSTIC VALUE. THIS WORK OUTLINES A DETAILED PROTOCOL FOR AN MBD-SEQ AND BIOINFORMATICS PIPELINE DEVELOPED FOR THE COMPREHENSIVE ANALYSIS OF GLOBAL METHYLATION PROFILES IN HIGHLY CPG-RICH REGIONS USING CLL PATIENT SAMPLES. FINALLY, A PROTEIN-CODING GENE AND AN LNCRNA WERE VALIDATED USING PYROSEQUENCING, WHICH IS A HIGHLY QUANTITATIVE METHOD TO ANALYZE CPG METHYLATION LEVELS TO FURTHER CORROBORATE THE FINDINGS FROM THE MBD-SEQ PROTOCOL. 2017 2 1433 47 DIFFERENTIAL GENOME-WIDE ARRAY-BASED METHYLATION PROFILES IN PROGNOSTIC SUBSETS OF CHRONIC LYMPHOCYTIC LEUKEMIA. GLOBAL HYPOMETHYLATION AND REGIONAL HYPERMETHYLATION ARE WELL-KNOWN EPIGENETIC FEATURES OF CANCER; HOWEVER, IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), STUDIES ON GENOME-WIDE EPIGENETIC MODIFICATIONS ARE LIMITED. HERE, WE ANALYZED THE GLOBAL METHYLATION PROFILES IN CLL, BY APPLYING HIGH-RESOLUTION METHYLATION MICROARRAYS (27,578 CPG SITES) TO 23 CLL SAMPLES, BELONGING TO THE IMMUNOGLOBULIN HEAVY-CHAIN VARIABLE (IGHV) MUTATED (FAVORABLE) AND IGHV UNMUTATED/IGHV3-21 (POOR-PROGNOSTIC) SUBSETS. OVERALL, RESULTS DEMONSTRATED SIGNIFICANT DIFFERENCES IN METHYLATION PATTERNS BETWEEN THESE SUBGROUPS. SPECIFICALLY, IN IGHV UNMUTATED CLL, WE IDENTIFIED METHYLATION OF 7 KNOWN OR CANDIDATE TUMOR SUPPRESSOR GENES (EG, VHL, ABI3, AND IGSF4) AS WELL AS 8 UNMETHYLATED GENES INVOLVED IN CELL PROLIFERATION AND TUMOR PROGRESSION (EG, ADORA3 AND PRF1 ENHANCING THE NUCLEAR FACTOR-KAPPAB AND MITOGEN-ACTIVATED PROTEIN KINASE PATHWAYS, RESPECTIVELY). IN CONTRAST, THESE LATTER GENES WERE SILENCED BY METHYLATION IN IGHV MUTATED PATIENTS. THE ARRAY DATA WERE VALIDATED FOR SELECTED GENES USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION, QUANTITATIVE REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION, AND BISULFITE SEQUENCING. FINALLY, THE SIGNIFICANCE OF DNA METHYLATION IN REGULATING GENE PROMOTERS WAS SHOWN BY REINDUCING 4 METHYLATED TUMOR SUPPRESSOR GENES (EG, VHL AND ABI3) IN IGHV UNMUTATED SAMPLES USING THE METHYL-INHIBITOR 5-AZA-2'-DEOXYCYTIDINE. TAKEN TOGETHER, OUR DATA FOR THE FIRST TIME REVEAL DIFFERENCES IN GLOBAL METHYLATION PROFILES BETWEEN PROGNOSTIC SUBSETS OF CLL, WHICH MAY UNFOLD EPIGENETIC SILENCING MECHANISMS INVOLVED IN CLL PATHOGENESIS. 2010 3 2639 32 EPIGENOMIC ANALYSIS DETECTS WIDESPREAD GENE-BODY DNA HYPOMETHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA. WE HAVE EXTENSIVELY CHARACTERIZED THE DNA METHYLOMES OF 139 PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) WITH MUTATED OR UNMUTATED IGHV AND OF SEVERAL MATURE B-CELL SUBPOPULATIONS THROUGH THE USE OF WHOLE-GENOME BISULFITE SEQUENCING AND HIGH-DENSITY MICROARRAYS. THE TWO MOLECULAR SUBTYPES OF CLL HAVE DIFFERING DNA METHYLOMES THAT SEEM TO REPRESENT EPIGENETIC IMPRINTS FROM DISTINCT NORMAL B-CELL SUBPOPULATIONS. DNA HYPOMETHYLATION IN THE GENE BODY, TARGETING MOSTLY ENHANCER SITES, WAS THE MOST FREQUENT DIFFERENCE BETWEEN NAIVE AND MEMORY B CELLS AND BETWEEN THE TWO MOLECULAR SUBTYPES OF CLL AND NORMAL B CELLS. ALTHOUGH DNA METHYLATION AND GENE EXPRESSION WERE POORLY CORRELATED, WE IDENTIFIED GENE-BODY CPG DINUCLEOTIDES WHOSE METHYLATION WAS POSITIVELY OR NEGATIVELY ASSOCIATED WITH EXPRESSION. WE HAVE ALSO RECOGNIZED A DNA METHYLATION SIGNATURE THAT DISTINGUISHES NEW CLINICO-BIOLOGICAL SUBTYPES OF CLL. WE PROPOSE AN EPIGENOMIC SCENARIO IN WHICH DIFFERENTIAL METHYLATION IN THE GENE BODY MAY HAVE FUNCTIONAL AND CLINICAL IMPLICATIONS IN LEUKEMOGENESIS. 2012 4 1620 33 DNA METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL SILENCING IN MALIGNANT GLIOMA: A COMBINED WHOLE-GENOME MICROARRAY AND PROMOTER ARRAY ANALYSIS. EPIGENETIC INACTIVATION OF TUMOR SUPPRESSOR GENES IS A COMMON FEATURE IN HUMAN CANCER. PROMOTER HYPERMETHYLATION AND HISTONE DEACETYLATION ARE REVERSIBLE EPIGENETIC MECHANISMS ASSOCIATED WITH TRANSCRIPTIONAL REGULATION. DNA METHYLTRANSFERASES (DNMT1 AND DNMT3B) REGULATE AND MAINTAIN PROMOTER METHYLATION AND ARE OVEREXPRESSED IN HUMAN CANCER. WE PERFORMED WHOLE-GENOME MICROARRAY ANALYSIS TO IDENTIFY GENES WITH ALTERED EXPRESSION AFTER RNAI-INDUCED SUPPRESSION OF DNMT IN A GLIOBLASTOMA MULTIFORME (GBM) CELL LINE. WE THEN IDENTIFIED GENES WITH BOTH DECREASED EXPRESSION AND EVIDENCE OF PROMOTER CPG ISLAND HYPERMETHYLATION IN GBM TISSUE SAMPLES USING A COMBINED WHOLE-GENOME MICROARRAY TRANSCRIPTOME ANALYSIS IN CONJUNCTION WITH A PROMOTER ARRAY ANALYSIS AFTER DNA IMMUNOPRECIPITATION WITH ANTI-5-METHYLCYTIDINE. DNMT1 AND 3B KNOCKDOWN RESULTED IN THE RESTORED EXPRESSION OF 308 GENES THAT ALSO CONTAINED PROMOTER REGION HYPERMETHYLATION. OF THESE, 43 WERE ALSO FOUND TO BE DOWNREGULATED IN GBM TISSUE SAMPLES. THREE DOWNREGULATED GENES WITH HYPERMETHYLATED PROMOTERS AND RESTORED EXPRESSION IN RESPONSE TO ACUTE DNMT SUPPRESSION WERE ASSAYED FOR METHYLATION CHANGES USING BISULFITE SEQUENCE ANALYSIS OF THE PROMOTER REGION AFTER CHRONIC DNMT SUPPRESSION. RESTORATION OF GENE EXPRESSION WAS NOT ASSOCIATED WITH CHANGES IN PROMOTER REGION METHYLATION, BUT RATHER WITH CHANGES IN HISTONE METHYLATION AND CHROMATIN CONFORMATION. TWO OF THE IDENTIFIED GENES EXHIBITED GROWTH SUPPRESSIVE ACTIVITY IN IN VITRO ASSAYS. COMBINING TARGETED GENETIC MANIPULATIONS WITH COMPREHENSIVE GENOMIC AND EXPRESSION ANALYSES PROVIDES A POTENTIALLY POWERFUL NEW APPROACH FOR IDENTIFYING EPIGENETICALLY REGULATED GENES IN GBM. 2009 5 3138 68 GLOBAL DNA METHYLATION PROFILING REVEALS NEW INSIGHTS INTO EPIGENETICALLY DEREGULATED PROTEIN CODING AND LONG NONCODING RNAS IN CLL. BACKGROUND: METHYL-CPG-BINDING DOMAIN PROTEIN ENRICHED GENOME-WIDE SEQUENCING (MBD-SEQ) IS A ROBUST AND POWERFUL METHOD FOR ANALYZING METHYLATED CPG-RICH REGIONS WITH COMPLETE GENOME-WIDE COVERAGE. IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), THE ROLE OF CPG METHYLATED REGIONS ASSOCIATED WITH TRANSCRIBED LONG NONCODING RNAS (LNCRNA) AND REPETITIVE GENOMIC ELEMENTS ARE POORLY UNDERSTOOD. BASED ON MBD-SEQ, WE CHARACTERIZED THE GLOBAL METHYLATION PROFILE OF HIGH CPG-RICH REGIONS IN DIFFERENT CLL PROGNOSTIC SUBGROUPS BASED ON IGHV MUTATIONAL STATUS. RESULTS: OUR STUDY IDENTIFIED 5800 HYPERMETHYLATED AND 12,570 HYPOMETHYLATED CLL-SPECIFIC DIFFERENTIALLY METHYLATED GENES (CLLDMGS) COMPARED TO NORMAL CONTROLS. FROM CLLDMGS, 40 % OF HYPERMETHYLATED AND 60 % OF HYPOMETHYLATED GENES WERE MAPPED TO NONCODING RNAS. IN ADDITION, WE FOUND THAT THE MAJOR REPETITIVE ELEMENTS SUCH AS SHORT INTERSPERSED ELEMENTS (SINE) AND LONG INTERSPERSED ELEMENTS (LINE) HAVE A HIGH PERCENTAGE OF CLLDMRS (DIFFERENTIALLY METHYLATED REGIONS) IN IGHV SUBGROUPS COMPARED TO NORMAL CONTROLS. FINALLY, TWO NOVEL LNCRNAS (HYPERMETHYLATED CRNDE AND HYPOMETHYLATED AC012065.7) WERE VALIDATED IN AN INDEPENDENT CLL SAMPLE COHORT (48 SAMPLES) COMPARED WITH 6 NORMAL SORTED B CELL SAMPLES USING QUANTITATIVE PYROSEQUENCING ANALYSIS. THE METHYLATION LEVELS SHOWED AN INVERSE CORRELATION TO GENE EXPRESSION LEVELS ANALYZED BY REAL-TIME QUANTITATIVE PCR. NOTABLY, SURVIVAL ANALYSIS REVEALED THAT HYPERMETHYLATION OF CRNDE AND HYPOMETHYLATION OF AC012065.7 CORRELATED WITH AN INFERIOR OUTCOME. CONCLUSIONS: THUS, OUR COMPREHENSIVE METHYLATION ANALYSIS BY MBD-SEQ PROVIDED NOVEL HYPER AND HYPOMETHYLATED LONG NONCODING RNAS, REPETITIVE ELEMENTS, ALONG WITH PROTEIN CODING GENES AS POTENTIAL EPIGENETIC-BASED CLL-SIGNATURE GENES INVOLVED IN DISEASE PATHOGENESIS AND PROGNOSIS. 2016 6 2771 40 EXTENSIVE PROMOTER DNA HYPERMETHYLATION AND HYPOMETHYLATION IS ASSOCIATED WITH ABERRANT MICRORNA EXPRESSION IN CHRONIC LYMPHOCYTIC LEUKEMIA. DYSREGULATED MICRORNA (MIRNA) EXPRESSION CONTRIBUTES TO THE PATHOGENESIS OF HEMATOPOIETIC MALIGNANCIES, INCLUDING CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). HOWEVER, AN UNDERSTANDING OF THE MECHANISMS THAT CAUSE ABERRANT MIRNA TRANSCRIPTIONAL CONTROL IS LACKING. IN THIS STUDY, WE COMPREHENSIVELY INVESTIGATED THE ROLE AND EXTENT OF MIRNA EPIGENETIC REGULATION IN CLL. GENOME-WIDE PROFILING CONDUCTED ON 24 CLL AND 10 HEALTHY B CELL SAMPLES REVEALED GLOBAL DNA METHYLATION PATTERNS UPSTREAM OF MIRNA SEQUENCES THAT DISTINGUISHED MALIGNANT FROM HEALTHY CELLS AND IDENTIFIED PUTATIVE MIRNA PROMOTERS. INTEGRATION OF DNA METHYLATION AND MIRNA PROMOTER DATA LED TO THE IDENTIFICATION OF 128 RECURRENT MIRNA TARGETS FOR ABERRANT PROMOTER DNA METHYLATION. DNA HYPOMETHYLATION ACCOUNTED FOR MORE THAN 60% OF ALL ABERRANT PROMOTER-ASSOCIATED DNA METHYLATION IN CLL, AND PROMOTER DNA HYPOMETHYLATION WAS RESTRICTED TO WELL-DEFINED REGIONS. INDIVIDUAL HYPER- AND HYPOMETHYLATED PROMOTERS ALLOWED DISCRIMINATION OF CLL SAMPLES FROM HEALTHY CONTROLS. PROMOTER DNA METHYLATION PATTERNS WERE CONFIRMED IN AN INDEPENDENT PATIENT COHORT, WITH 11 MIRNAS CONSISTENTLY SHOWING AN INVERSE CORRELATION BETWEEN DNA METHYLATION STATUS AND EXPRESSION LEVEL. TOGETHER, OUR FINDINGS CHARACTERIZE THE ROLE OF EPIGENETIC CHANGES IN THE REGULATION OF MIRNA TRANSCRIPTION AND CREATE A REPOSITORY OF DISEASE-SPECIFIC PROMOTER REGIONS THAT MAY PROVIDE ADDITIONAL INSIGHTS INTO THE PATHOGENESIS OF CLL. 2012 7 6613 39 ULTRADEEP BISULFITE SEQUENCING ANALYSIS OF DNA METHYLATION PATTERNS IN MULTIPLE GENE PROMOTERS BY 454 SEQUENCING. WE DEVELOPED A NOVEL APPROACH FOR CONDUCTING MULTISAMPLE, MULTIGENE, ULTRADEEP BISULFITE SEQUENCING ANALYSIS OF DNA METHYLATION PATTERNS IN CLINICAL SAMPLES. A MASSIVELY PARALLEL SEQUENCING-BY-SYNTHESIS METHOD (454 SEQUENCING) WAS USED TO DIRECTLY SEQUENCE >100 BISULFITE PCR PRODUCTS IN A SINGLE SEQUENCING RUN WITHOUT SUBCLONING. WE SHOWED THE UTILITY, ROBUSTNESS, AND SUPERIORITY OF THIS APPROACH BY ANALYZING METHYLATION IN 25 GENE-RELATED CPG RICH REGIONS FROM >40 CASES OF PRIMARY CELLS, INCLUDING NORMAL PERIPHERAL BLOOD LYMPHOCYTES, ACUTE LYMPHOBLASTIC LEUKEMIA (ALL), CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), FOLLICULAR LYMPHOMA (FL), AND MANTLE CELL LYMPHOMA (MCL). A TOTAL OF 294,631 SEQUENCES WAS GENERATED WITH AN AVERAGE READ LENGTH OF 131 BP. ON AVERAGE, >1,600 INDIVIDUAL SEQUENCES WERE GENERATED FOR EACH PCR AMPLICON FAR BEYOND THE FEW CLONES (<20) TYPICALLY ANALYZED BY TRADITIONAL BISULFITE SEQUENCING. COMPREHENSIVE ANALYSIS OF CPG METHYLATION PATTERNS AT A SINGLE DNA MOLECULE LEVEL USING CLUSTERING ALGORITHMS REVEALED DIFFERENTIAL METHYLATION PATTERNS BETWEEN DISEASES. A SIGNIFICANT INCREASE IN METHYLATION WAS DETECTED IN ALL AND FL SAMPLES COMPARED WITH CLL AND MCL. FURTHERMORE, A PROGRESSIVE SPREADING OF METHYLATION WAS DETECTED FROM THE PERIPHERY TOWARD THE CENTER OF SELECT CPG ISLANDS IN THE ALL AND FL SAMPLES. THE ULTRADEEP SEQUENCING ALSO ALLOWED SIMULTANEOUS ANALYSIS OF GENETIC AND EPIGENETIC DATA AND REVEALED AN ASSOCIATION BETWEEN A SINGLE NUCLEOTIDE POLYMORPHISM AND THE METHYLATION PRESENT IN THE LRP1B PROMOTER. THIS NEW GENERATION OF METHYLOME SEQUENCING WILL PROVIDE DIGITAL PROFILES OF ABERRANT DNA METHYLATION FOR INDIVIDUAL HUMAN CANCERS AND OFFERS A ROBUST METHOD FOR THE EPIGENETIC CLASSIFICATION OF TUMOR SUBTYPES. 2007 8 3062 41 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 9 18 39 5-AZACYTIDINE MODULATES CPG METHYLATION LEVELS OF EZH2 AND NOTCH1 IN MYELODYSPLASTIC SYNDROMES. PURPOSE: MOLECULAR MECHANISMS OF RESPONSE TO HYPOMETHYLATING AGENTS IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES (MDS) AND CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) STILL REMAIN LARGELY UNKNOWN. THEREFORE, THE EFFECTS OF 5-AZACYTIDINE (AZA) ON CLONAL ARCHITECTURE AND DNA METHYLATION WERE INVESTIGATED IN THIS STUDY. METHODS: USING NEXT-GENERATION SEQUENCING (NGS), 30 MYELOID LEUKEMIA-ASSOCIATED GENES WERE ANALYZED IN 15 MDS/CMML PATIENTS WITH EXCELLENT RESPONSE TO AZA. EFFECTS ON METHYLATION LEVELS WERE ANALYZED BY QUANTITATIVE METHYLATION ANALYSIS USING PYROSEQUENCING FOR THE GLOBAL METHYLATION MARKER LINE-1 IN PATIENTS AND MYELOID CELL LINES. VARIOUS MYELOID CELL LINES AND A HEALTHY COHORT WERE SCREENED FOR METHYLATION LEVELS IN 23 GENES. SELECTED TARGETS WERE VERIFIED ON THE MDS/CMML COHORT. RESULTS: THE STUDY PRESENTED HERE SHOWED A STABLE VARIANT ALLELE FREQUENCY AND STABLE GLOBAL METHYLATION LEVELS IN RESPONDING PATIENTS. A SIGNIFICANT DEMETHYLATION OF EZH2 AND NOTCH1 WAS REVEALED IN PATIENTS WITH AZA RESPONSE. CONCLUSIONS: A RESPONSE TO AZA IS NOT ASSOCIATED WITH ERADICATION OF MALIGNANT CLONES, BUT RATHER WITH A STABILIZATION OF THE CLONAL ARCHITECTURE. WE SUGGEST CHANGES IN CPG METHYLATION LEVELS OF EZH2 AND NOTCH1 AS POTENTIAL TARGETS OF EPIGENETIC RESPONSE TO AZA TREATMENT WHICH MAY ALSO SERVE AS USEFUL BIOMARKERS AFTER CLINICAL EVALUATION. 2019 10 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 11 157 32 ABERRANT METHYLATION OF TUMOUR SUPPRESSOR GENE ADAM12 IN CHRONIC LYMPOCYTIC LEUKEMIA PATIENTS: APPLICATION OF METHYLATION SPECIFIC-PCR TECHNIQUE. OBJECTIVE: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A COMMON LEUKEMIA AMONG CAUCASIANS BUT RARE IN ASIANS POPULATION. WE POSTULATED THAT ABERRANT METHYLATION EITHER HYPERMETHYLATION OR PARTIAL METHYLATION MIGHT BE ONE OF THE SILENCING MECHANISMS THAT INACTIVATES THE TUMOUR SUPPRESSOR GENES IN CLL. THIS STUDY AIMED TO COMPARE THE METHYLATION STATUS OF TUMOUR SUPPRESSOR GENE, ADAM12, AMONG CLL PATIENTS AND NORMAL INDIVIDUALS. WE ALSO EVALUATED THE ASSOCIATION BETWEEN METHYLATION OF ADAM12 AND CLINICAL AND DEMOGRAPHIC CHARACTERISTICS OF THE PARTICIPANTS. METHODS: A TOTAL OF 25 CLL PATIENTS AND 25 NORMAL INDIVIDUALS WERE RECRUITED IN THIS STUDY. THE METHYLATION STATUS OF ADAM12 WAS DETERMINED USING METHYLATION-SPECIFIC PCR (MSP); WHEREAS, DNA SEQUENCING METHOD WAS APPLIED FOR VALIDATION OF THE MSP RESULTS. RESULTS: AMONG CLL PATIENTS, 12 (48%) WERE PARTIALLY METHYLATED AND 13 (52%) WERE UNMETHYLATED. MEANWHILE, 5 (20%) AND 20 (80.6%) OF HEALTHY INDIVIDUALS WERE PARTIALLY METHYLATED AND UNMETHYLATED, RESPECTIVELY. THERE WAS A STATISTICALLY SIGNIFICANT ASSOCIATION BETWEEN THE STATUS OF METHYLATION AT ADAM12 AND THE PRESENCE OF CLL (P=0.037). CONCLUSION: THE ABERRANT METHYLATION OF ADAM12 FOUND IN THIS STUDY USING MSP ASSAY MAY PROVIDE NEW EXPOSURE TO CLL THAT MAY IMPROVE THE GAPS INVOLVED IN GENETIC EPIGENETIC STUDY IN CLL. 2021 12 3444 30 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 13 3132 50 GLOBAL DISTRIBUTION OF DNA HYDROXYMETHYLATION AND DNA METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA. BACKGROUND: CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) HAS BEEN A GOOD MODEL SYSTEM TO UNDERSTAND THE FUNCTIONAL ROLE OF 5-METHYLCYTOSINE (5-MC) IN CANCER PROGRESSION. MORE RECENTLY, AN OXIDIZED FORM OF 5-MC, 5-HYDROXYMETHYLCYTOSINE (5-HMC) HAS GAINED LOT OF ATTENTION AS A REGULATORY EPIGENETIC MODIFICATION WITH PROGNOSTIC AND DIAGNOSTIC IMPLICATIONS FOR SEVERAL CANCERS. HOWEVER, THERE IS NO GLOBAL STUDY EXPLORING THE ROLE OF 5-HYDROXYMETHYLCYTOSINE (5-HMC) LEVELS IN CLL. HEREIN, USING MASS SPECTROMETRY AND HMEDIP-SEQUENCING, WE ANALYSED THE DYNAMICS OF 5-HMC DURING B CELL MATURATION AND CLL PATHOGENESIS. RESULTS: WE SHOW THAT NAIVE B-CELLS HAD HIGHER LEVELS OF 5-HMC AND 5-MC COMPARED TO NON-CLASS SWITCHED AND CLASS-SWITCHED MEMORY B-CELLS. WE FOUND A SIGNIFICANT DECREASE IN GLOBAL 5-MC LEVELS IN CLL PATIENTS (N = 15) COMPARED TO NAIVE AND MEMORY B CELLS, WITH NO CHANGES DETECTED BETWEEN THE CLL PROGNOSTIC GROUPS. ON THE OTHER HAND, GLOBAL 5-HMC LEVELS OF CLL PATIENTS WERE SIMILAR TO MEMORY B CELLS AND REDUCED COMPARED TO NAIVE B CELLS. INTERESTINGLY, 5-HMC LEVELS WERE INCREASED AT REGULATORY REGIONS SUCH AS GENE-BODY, CPG ISLAND SHORES AND SHELVES AND 5-HMC DISTRIBUTION OVER THE GENE-BODY POSITIVELY CORRELATED WITH DEGREE OF TRANSCRIPTIONAL ACTIVITY. IMPORTANTLY, CLL SAMPLES SHOWED ABERRANT 5-HMC AND 5-MC PATTERN OVER GENE-BODY COMPARED TO WELL-DEFINED PATTERNS IN NORMAL B-CELLS. INTEGRATED ANALYSIS OF 5-HMC AND RNA-SEQUENCING FROM CLL DATASETS IDENTIFIED THREE NOVEL ONCOGENIC DRIVERS THAT COULD HAVE POTENTIAL ROLES IN CLL DEVELOPMENT AND PROGRESSION. CONCLUSIONS: THUS, OUR STUDY SUGGESTS THAT THE GLOBAL LOSS OF 5-HMC, ACCOMPANIED BY ITS SIGNIFICANT INCREASE AT THE GENE REGULATORY REGIONS, CONSTITUTE A NOVEL HALLMARK OF CLL PATHOGENESIS. OUR COMBINED ANALYSIS OF 5-MC AND 5-HMC SEQUENCING PROVIDED INSIGHTS INTO THE POTENTIAL ROLE OF 5-HMC IN MODULATING GENE EXPRESSION CHANGES DURING CLL PATHOGENESIS. 2019 14 1968 31 EPIGENETIC ALTERATION OF THE SOCS1 GENE IN CHRONIC MYELOID LEUKAEMIA. THE EXPRESSION OF THE SUPPRESSOR OF CYTOKINE SIGNALLING-1 (SOCS1) PROTEIN IS INDUCED IN RESPONSE TO STIMULATION BY SEVERAL CYTOKINES. THE INDUCED SOCS1 INHIBITS THE SIGNALLING PATHWAY THROUGH THE ASSOCIATION WITH A VARIETY OF TYROSINE KINASE PROTEINS. IN THIS STUDY, THE MUTATION ANALYSES, CPG ISLAND METHYLATION STATUS, AND THE EXPRESSION OF THE SOCS1 GENE IN 112 CHRONIC MYELOID LEUKAEMIA (CML) SAMPLES, FIVE LEUKAEMIA CELL LINES, AND 30 NORMAL CONTROLS WERE ANALYSED. NO GENETIC MUTATIONS OF SOCS1 GENE WERE NOTED IN THE CML SAMPLES. THE SOCS1 GENE WAS HYPERMETHYLATED IN 67% AND 46% OF THE BLASTIC AND CHRONIC PHASE CML SAMPLES RESPECTIVELY (P < 0.0001). HOWEVER, THERE WAS NO METHYLATION OF THE SOCS1 GENE IN NORMAL CONTROLS OR CML IN MOLECULAR REMISSION. THE METHYLATION STATUS OF THE SOCS1 GENE IS CONSISTENT WITH THE RESULTS OF THE REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION AND IMMUNOCYTOCHEMISTRY STAINING. OUR RESULTS DEMONSTRATE THAT THE SOCS1 GENE SILENCING IS CAUSED BY THE METHYLATION OF CPG ISLANDS IN CML AND IS REVERSED TO AN UNMETHYLATED STATUS IN MOLECULAR REMISSION. AS SOCS1 HAS UNIVERSAL ACTIVITY TO NEGATIVELY REGULATE SEVERAL CYTOKINE SIGNALLING PATHWAYS, THE LOSS OF THE NEGATIVE REGULATION OF CYTOKINE SIGNALLING BY THE SOCS1 MAY PLAY A ROLE IN THE PATHOGENESIS OF CML PROGRESSION. 2003 15 1211 35 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 16 1577 32 DNA METHYLATION PROFILE IN CHRONIC MYELOMONOCYTIC LEUKEMIA ASSOCIATES WITH DISTINCT CLINICAL, BIOLOGICAL AND GENETIC FEATURES. CHROMOSOMAL ABNORMALITIES ARE DETECTED IN 20-30% OF PATIENTS WITH CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AND CORRELATE WITH PROGNOSIS. ON THE MUTATION LEVEL, DISRUPTIVE ALTERATIONS ARE PARTICULARLY FREQUENT IN CHROMATIN REGULATORY GENES. HOWEVER, LITTLE IS KNOWN ABOUT THE CONSEQUENTIAL ALTERATIONS IN THE EPIGENETIC MARKING OF THE GENOME. HERE, WE REPORT THE ANALYSIS OF GENOMIC DNA METHYLATION PATTERNS OF 64 CMML PATIENTS AND 10 HEALTHY CONTROLS, USING A DNA METHYLATION MICROARRAY FOCUSED ON PROMOTER REGIONS. DIFFERENTIAL METHYLATION ANALYSIS BETWEEN PATIENTS AND CONTROLS ALLOWED US TO IDENTIFY ABNORMALITIES IN DNA METHYLATION, INCLUDING HYPERMETHYLATION OF SPECIFIC GENES AND LARGE GENOME REGIONS WITH ABERRANT DNA METHYLATION. UNSUPERVISED HIERARCHICAL CLUSTER ANALYSIS IDENTIFIED TWO MAIN CLUSTERS THAT ASSOCIATED WITH THE CLINICAL, BIOLOGICAL, AND GENETIC FEATURES OF PATIENTS. GROUP 1 WAS ENRICHED IN PATIENTS WITH ADVERSE CLINICAL AND BIOLOGICAL CHARACTERISTICS AND POORER OVERALL AND PROGRESSION-FREE SURVIVAL. IN ADDITION, SIGNIFICANT DIFFERENCES IN DNA METHYLATION WERE OBSERVED BETWEEN PATIENTS WITH LOW RISK AND INTERMEDIATE/HIGH RISK KARYOTYPES AND BETWEEN TET2 MUTANT AND WILD TYPE PATIENTS. TAKEN TOGETHER, OUR RESULTS DEMONSTRATE THAT ALTERED DNA METHYLATION PATTERNS REFLECT THE CMML DISEASE STATE AND ALLOW TO IDENTIFY PATIENT GROUPS WITH DISTINCT CLINICAL FEATURES. 2018 17 812 45 CHANGES IN DNA METHYLATION PROFILES OF MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME PATIENTS REFLECT SYSTEMIC DYSFUNCTIONS. BACKGROUND: MYALGIC ENCEPHALOMYELITIS/CHRONIC FATIGUE SYNDROME (ME/CFS) IS A LIFELONG DEBILITATING DISEASE WITH A COMPLEX PATHOLOGY NOT YET CLEARLY DEFINED. SUSCEPTIBILITY TO ME/CFS INVOLVES GENETIC PREDISPOSITION AND EXPOSURE TO ENVIRONMENTAL FACTORS, SUGGESTING AN EPIGENETIC ASSOCIATION. EPIGENETIC STUDIES WITH OTHER ME/CFS COHORTS HAVE USED ARRAY-BASED TECHNOLOGY TO IDENTIFY DIFFERENTIALLY METHYLATED INDIVIDUAL SITES. CHANGES IN RNA QUANTITIES AND PROTEIN ABUNDANCE HAVE BEEN DOCUMENTED IN OUR PREVIOUS INVESTIGATIONS WITH THE SAME ME/CFS COHORT USED FOR THIS STUDY. RESULTS: DNA FROM A WELL-CHARACTERISED NEW ZEALAND COHORT OF 10 ME/CFS PATIENTS AND 10 AGE-/SEX-MATCHED HEALTHY CONTROLS WAS ISOLATED FROM PERIPHERAL BLOOD MONONUCLEAR (PBMC) CELLS, AND USED TO GENERATE REDUCED GENOME-SCALE DNA METHYLATION MAPS USING REDUCED REPRESENTATION BISULPHITE SEQUENCING (RRBS). THE SEQUENCING DATA WERE ANALYSED UTILISING THE DMAP ANALYSIS PIPELINE TO IDENTIFY DIFFERENTIALLY METHYLATED FRAGMENTS, AND THE METHYLKIT PIPELINE WAS USED TO QUANTIFY METHYLATION DIFFERENCES AT INDIVIDUAL CPG SITES. DMAP IDENTIFIED 76 DIFFERENTIALLY METHYLATED FRAGMENTS AND METHYLKIT IDENTIFIED 394 DIFFERENTIALLY METHYLATED CYTOSINES THAT INCLUDED BOTH HYPER- AND HYPO-METHYLATION. FOUR CLUSTERS WERE IDENTIFIED WHERE DIFFERENTIALLY METHYLATED DNA FRAGMENTS OVERLAPPED WITH OR WERE WITHIN CLOSE PROXIMITY TO MULTIPLE DIFFERENTIALLY METHYLATED INDIVIDUAL CYTOSINES. THESE CLUSTERS IDENTIFIED REGULATORY REGIONS FOR 17 PROTEIN ENCODING GENES RELATED TO METABOLIC AND IMMUNE ACTIVITY. ANALYSIS OF DIFFERENTIALLY METHYLATED GENE BODIES (EXONS/INTRONS) IDENTIFIED 122 UNIQUE GENES. COMPARISON WITH OTHER STUDIES ON PBMCS FROM ME/CFS PATIENTS AND CONTROLS WITH ARRAY TECHNOLOGY SHOWED 59% OF THE GENES IDENTIFIED IN THIS STUDY WERE ALSO FOUND IN ONE OR MORE OF THESE STUDIES. FUNCTIONAL PATHWAY ENRICHMENT ANALYSIS IDENTIFIED 30 ASSOCIATED PATHWAYS. THESE INCLUDED IMMUNE, METABOLIC AND NEUROLOGICAL-RELATED FUNCTIONS DIFFERENTIALLY REGULATED IN ME/CFS PATIENTS COMPARED TO THE MATCHED HEALTHY CONTROLS. CONCLUSIONS: MAJOR DIFFERENCES WERE IDENTIFIED IN THE DNA METHYLATION PATTERNS OF ME/CFS PATIENTS THAT CLEARLY DISTINGUISHED THEM FROM THE HEALTHY CONTROLS. OVER HALF FOUND IN GENE BODIES WITH RRBS IN THIS STUDY HAD BEEN IDENTIFIED IN OTHER ME/CFS STUDIES USING THE SAME CELLS BUT WITH ARRAY TECHNOLOGY. WITHIN THE ENRICHED FUNCTIONAL IMMUNE, METABOLIC AND NEUROLOGICAL PATHWAYS, A NUMBER OF ENRICHED NEUROTRANSMITTER AND NEUROPEPTIDE REACTOME PATHWAYS HIGHLIGHTED A DISTURBED NEUROLOGICAL PATHOPHYSIOLOGY WITHIN THE PATIENT GROUP. 2020 18 349 39 ALTERED DNA METHYLATION PROFILES IN SF3B1 MUTATED CLL PATIENTS. MUTATIONS IN SPLICING FACTOR GENES HAVE A SEVERE IMPACT ON THE SURVIVAL OF CANCER PATIENTS. SPLICING FACTOR 3B SUBUNIT 1 (SF3B1) IS ONE OF THE MOST FREQUENTLY MUTATED GENES IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL); PATIENTS CARRYING THESE MUTATIONS HAVE A POOR PROGNOSIS. SINCE THE SPLICING MACHINERY AND THE EPIGENOME ARE CLOSELY INTERCONNECTED, WE INVESTIGATED WHETHER THESE ALTERATIONS MAY AFFECT THE EPIGENOMES OF CLL PATIENTS. WHILE AN OVERALL HYPOMETHYLATION DURING CLL CARCINOGENESIS HAS BEEN OBSERVED, THE INTERPLAY BETWEEN THE EPIGENETIC STAGE OF THE ORIGINATING B CELLS AND SF3B1 MUTATIONS, AND THE SUBSEQUENT EFFECT OF THE MUTATIONS ON METHYLATION ALTERATIONS IN CLL, HAVE NOT BEEN INVESTIGATED. WE PROFILED THE GENOME-WIDE DNA METHYLATION PATTERNS OF 27 CLL PATIENTS WITH AND WITHOUT SF3B1 MUTATIONS AND IDENTIFIED LOCAL DECREASES IN METHYLATION LEVELS IN SF3B1(MUT) CLL PATIENTS AT 67 GENOMIC REGIONS, MOSTLY IN PROXIMITY TO TELOMERIC REGIONS. THESE DIFFERENTIALLY METHYLATED REGIONS (DMRS) WERE ENRICHED IN GENE BODIES OF CANCER-RELATED SIGNALING GENES, E.G., NOTCH1, HTRA3, AND BCL9L. IN OUR STUDY, SF3B1 MUTATIONS EXCLUSIVELY EMERGED IN TWO OUT OF THREE EPIGENETIC STAGES OF THE ORIGINATING B CELLS. HOWEVER, NOT ALL THE DMRS COULD BE ASSOCIATED WITH THE METHYLATION PROGRAMMING OF B CELLS DURING DEVELOPMENT, SUGGESTING THAT MUTATIONS IN SF3B1 CAUSE ADDITIONAL EPIGENETIC ABERRATIONS DURING CARCINOGENESIS. 2021 19 1581 27 DNA METHYLATION PROFILES IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS TREATED WITH CHEMOIMMUNOTHERAPY. BACKGROUND: IN ORDER TO GAIN INSIGHT INTO THE CONTRIBUTION OF DNA METHYLATION TO DISEASE PROGRESSION OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), USING 450K ILLUMINA ARRAYS, WE DETERMINED THE DNA METHYLATION PROFILES IN PAIRED PRE-TREATMENT/RELAPSE SAMPLES FROM 34 CLL PATIENTS TREATED WITH CHEMOIMMUNOTHERAPY, MOSTLY (N = 31) WITH THE FLUDARABINE-CYCLOPHOSPHAMIDE-RITUXIMAB (FCR) REGIMEN. RESULTS: THE EXTENT OF IDENTIFIED CHANGES IN CLL CELLS VERSUS MEMORY B CELLS FROM HEALTHY DONORS WAS TERMED "EPIGENETIC BURDEN" (EB) WHEREAS THE NUMBER OF CHANGES BETWEEN THE PRE-TREATMENT VERSUS THE RELAPSE SAMPLE WAS TERMED "RELAPSE CHANGES" (RC). SIGNIFICANT (P < 0.05) ASSOCIATIONS WERE IDENTIFIED BETWEEN (I) HIGH EB AND SHORT TIME-TO-FIRST-TREATMENT (TTFT); AND, (II) FEW RCS AND SHORT TIME-TO-RELAPSE. BOTH THE EB AND THE RC CLUSTERED IN SPECIFIC GENOMIC REGIONS AND CHROMATIN STATES, INCLUDING REGULATORY REGIONS CONTAINING BINDING SITES OF TRANSCRIPTION FACTORS IMPLICATED IN B CELL AND CLL BIOLOGY. CONCLUSIONS: OVERALL, WE SHOW THAT DNA METHYLATION IN CLL FOLLOWS DIFFERENT DYNAMICS IN RESPONSE TO CHEMOIMMUNOTHERAPY. THESE EPIGENETIC ALTERATIONS WERE LINKED WITH SPECIFIC CLINICAL AND BIOLOGICAL FEATURES. 2019 20 2436 29 EPIGENETIC SILENCING OF SOCS3 IDENTIFIES A SUBSET OF PROSTATE CANCER WITH AN AGGRESSIVE BEHAVIOR. BACKGROUND: CHRONIC INFLAMMATION AND SUBSEQUENT TISSUTAL ALTERATIONS MAY PLAY A KEY ROLE IN PROSTATE CARCINOGENESIS. IN THIS WAY, MOLECULAR ALTERATIONS OF THE SUPPRESSOR OF CYTOKINE SIGNALING 3 (SOCS3), ONE OF THE MOST IMPORTANT INHIBITORY MOLECULE OF INFLAMMATORY SIGNAL TRANSDUCTION CIRCUITRIES, COULD CONTRIBUTE TO EXPLAIN THE PLEIOTROPIC ROLE OF INTERLEUKIN-6 (IL-6) IN THIS TYPE OF CANCER. METHODS: WE ANALYZED THE METHYLATION STATUS AND MRNA EXPRESSION OF SOCS3 IN 20 BENIGN PROSTATE HYPERPLASIAS (BPH) AND IN 51 PROSTATE CANCER SPECIMENS. WE ANALYZED THE SOCS3 METHYLATION STATUS USING METHYLATION-SPECIFIC PCR. HYPERMETHYLATION WAS CONFIRMED BY SEQUENCING AFTER SUBCLONING. EPIGENETIC SILENCING OF THIS GENE WAS ALSO DEMONSTRATED BY REAL-TIME PCR AND BY IMMUNOHISTOCHEMISTRY. RESULTS AND CORRELATION WITH CLINICAL DATA WERE STATISTICALLY ANALYZED. RESULTS: WE FOUND THAT THE PROMOTER OF SOCS3 WAS METHYLATED IN 39.2% OF PROSTATE CANCER. ON THE CONTRARY, ALL BPH AND NORMAL CONTROLS HAD AN UNMETHYLATED PATTERN. REAL-TIME ANALYSIS SHOWED THAT IN METHYLATED CASES SOCS3 MRNA EXPRESSION WAS REDUCED BY THREE AND FOUR FOLDS AS COMPARED TO BPH AND UNMETHYLATED CASES, RESPECTIVELY. INTERESTINGLY, SOCS3 MRNA LEVEL WAS HIGHER IN UNMETHYLATED PROSTATE CANCER THAN IN BPH. THE IMMUNOHISTOCHEMICAL STAINING ANALYSIS FOR SOCS 3 CONFIRMED MRNA RESULTS. MOREOVER, METHYLATION OF SOCS3 PROMOTER SIGNIFICANTLY ASSOCIATED WITH INTERMEDIATE-HIGH GRADE GLEASON SCORE (P = 0.0007) AND WITH AN UNFAVORABLE CLINICAL OUTCOME (P = 0.0019). CONCLUSIONS: OUR DATA SUGGEST THAT SOCS3 HYPERMETHYLATION MAY BE INVOLVED IN THE PATHOGENESIS OF PROSTATE CANCER AND COULD IDENTIFY A TUMOR SUBSET WITH AN AGGRESSIVE BEHAVIOR. 2011