1 1138 101 COMPUTATIONAL METHODS FOR DETECTION OF DIFFERENTIALLY METHYLATED REGIONS USING KERNEL DISTANCE AND SCAN STATISTICS. MOTIVATION: RESEARCHERS IN GENOMICS ARE INCREASINGLY INTERESTED IN EPIGENETIC FACTORS SUCH AS DNA METHYLATION BECAUSE THEY PLAY AN IMPORTANT ROLE IN REGULATING GENE EXPRESSION WITHOUT CHANGES IN THE SEQUENCE OF DNA. ABNORMAL DNA METHYLATION IS ASSOCIATED WITH MANY HUMAN DISEASES. RESULTS: WE PROPOSE TWO DIFFERENT APPROACHES TO TEST FOR DIFFERENTIALLY METHYLATED REGIONS (DMRS) ASSOCIATED WITH COMPLEX TRAITS, WHILE ACCOUNTING FOR CORRELATIONS AMONG CPG SITES IN THE DMRS. THE FIRST APPROACH IS A NONPARAMETRIC METHOD USING A KERNEL DISTANCE STATISTIC AND THE SECOND ONE IS A LIKELIHOOD-BASED METHOD USING A BINOMIAL SPATIAL SCAN STATISTIC. THE KERNEL DISTANCE METHOD USES THE KERNEL FUNCTION, WHILE THE BINOMIAL SCAN STATISTIC APPROACH USES A MIXED-EFFECTS MODEL TO INCORPORATE CORRELATIONS AMONG CPG SITES. EXTENSIVE SIMULATIONS SHOW THAT BOTH APPROACHES HAVE EXCELLENT CONTROL OF TYPE I ERROR, AND BOTH HAVE REASONABLE STATISTICAL POWER. THE BINOMIAL SCAN STATISTIC APPROACH APPEARS TO HAVE HIGHER POWER, WHILE THE KERNEL DISTANCE METHOD IS COMPUTATIONALLY FASTER. THE PROPOSED METHODS ARE DEMONSTRATED USING DATA FROM A CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) STUDY. 2019 2 1485 37 DMRFUSION: A DIFFERENTIALLY METHYLATED REGION DETECTION TOOL BASED ON THE RANKED FUSION METHOD. DNA METHYLATION IS AN IMPORTANT EPIGENETIC MODIFICATION INVOLVED IN MANY BIOLOGICAL PROCESSES AND DISEASES. COMPUTATIONAL ANALYSIS OF DIFFERENTIALLY METHYLATED REGIONS (DMRS) COULD EXPLORE THE UNDERLYING REASONS OF METHYLATION. DMRFUSION IS PRESENTED AS A USEFUL TOOL FOR COMPREHENSIVE DNA METHYLATION ANALYSIS OF DMRS ON METHYLATION SEQUENCING DATA. THIS TOOL IS DESIGNED BASE ON THE INTEGRATION OF SEVERAL RANKING METHODS; INFORMATION GAIN, BETWEEN VERSUS WITHIN CLASS SCATTER RATIO, FISHER RATIO, Z-SCORE AND WELCH'S T-TEST. IN THIS STUDY, DMRFUSION ON REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS) DATA IN CHRONIC LYMPHOCYTIC LEUKEMIA CANCER DISPLAYED 30 NOMINATED REGIONS AND CPG SITES WITH A MAXIMUM METHYLATION DIFFERENCE DETECTED IN THE HYPERMETHYLATION DMRS. WE REALIZED THAT DMRFUSION IS ABLE TO PROCESS METHYLATION SEQUENCING DATA IN AN EFFICIENT AND ACCURATE MANNER AND TO PROVIDE ANNOTATION AND VISUALIZATION FOR DMRS WITH HIGH FOLD DIFFERENCE SCORE (P-VALUE AND FDR<0.05 AND TYPE I ERROR: 0.04). 2018 3 3125 23 GHSR DNA HYPERMETHYLATION IS A COMMON EPIGENETIC ALTERATION OF HIGH DIAGNOSTIC VALUE IN A BROAD SPECTRUM OF CANCERS. IDENTIFICATION OF A SINGLE MOLECULAR TRAIT THAT IS DETERMINANT OF COMMON MALIGNANCIES MAY SERVE AS A POWERFUL DIAGNOSTIC SUPPLEMENT TO CANCER TYPE-SPECIFIC MARKERS. HERE, WE REPORT A DNA METHYLATION MARK THAT IS CHARACTERISTIC OF SEVEN STUDIED MALIGNANCIES, NAMELY CANCERS OF LUNG, BREAST, PROSTATE, PANCREAS, COLORECTUM, GLIOBLASTOMA AND B CELL CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) (N = 137). THIS MARK WAS DEFINED BY SUBSTANTIAL HYPERMETHYLATION AT THE PROMOTER AND FIRST EXON OF GROWTH HORMONE SECRETAGOUGE RECEPTOR (GHSR) THROUGH BISULFITE PYROSEQUENCING. THE DEGREE OF ABERRANT METHYLATION WAS CAPABLE OF ACCURATE DISCRIMINATION BETWEEN CANCER AND CONTROL SAMPLES. THE HIGHEST SENSITIVITY AND SPECIFICITY OF CANCER DETECTION WAS ACHIEVED FOR CANCERS OF PANCREAS, LUNG, BREAST AND CLL YIELDING THE AREA UNDER THE CURVE (AUC) VALUES OF 1.0000, 0.9952, 0.9800 AND 0.9400, RESPECTIVELY. NARROWING TO A SINGLE CPG SITE WITHIN THE GENE'S PROMOTER OR FOUR CONSECUTIVE CPG UNITS OF THE HIGHEST METHYLATION LEVELS WITHIN THE FIRST EXON IMPROVED THE DETECTION POWER. GHSR HYPERMETHYLATION WAS DETECTED ALREADY AT THE EARLY STAGE TUMORS. THE ACCURATE PERFORMANCE OF THIS MARKER WAS FURTHER REPLICATED IN AN INDEPENDENT SET OF PANCREATIC CANCER AND CONTROL SAMPLES (N = 78). THESE FINDINGS SUPPORT THE CANDIDATURE OF GHSR METHYLATION AS A HIGHLY ACCURATE PAN-CANCER MARKER. 2015 4 2967 33 GENETIC AND EPIGENETIC REGULATION OF CATECHOL-O-METHYLTRANSFERASE IN RELATION TO INFLAMMATION IN CHRONIC FATIGUE SYNDROME AND FIBROMYALGIA. BACKGROUND: CATECHOL-O-METHYLTRANSFERASE (COMT) HAS BEEN SHOWN TO INFLUENCE CLINICAL PAIN, DESCENDING MODULATION, AND EXERCISE-INDUCED SYMPTOM WORSENING. COMT REGULATES NOCICEPTIVE PROCESSING AND INFLAMMATION, KEY PATHOPHYSIOLOGICAL FEATURES OF CHRONIC FATIGUE SYNDROME AND FIBROMYALGIA (CFS/FM). WE AIMED TO DETERMINE THE INTERACTIONS BETWEEN GENETIC AND EPIGENETIC MECHANISMS REGULATING COMT AND ITS INFLUENCE ON INFLAMMATORY MARKERS AND SYMPTOMS IN PATIENTS WITH CFS/FM. METHODS: A CASE-CONTROL STUDY WITH REPEATED-MEASURES DESIGN WAS USED TO REDUCE THE CHANCE OF FALSE POSITIVE AND INCREASE THE POWER OF OUR FINDINGS. FIFTY-FOUR PARTICIPANTS (28 PATIENTS WITH CFS/FM AND 26 CONTROLS) WERE ASSESSED TWICE WITHIN 4 DAYS. THE ASSESSMENT INCLUDED CLINICAL QUESTIONNAIRES, NEUROPHYSIOLOGICAL ASSESSMENT (PAIN THRESHOLDS, TEMPORAL SUMMATION, AND CONDITIONED PAIN MODULATION), AND BLOOD WITHDRAWAL IN ORDER TO ASSESS RS4818, RS4633, AND RS4680 COMT POLYMORPHISMS AND PERFORM HAPLOTYPE ESTIMATION, DNA METHYLATION IN THE COMT GENE (BOTH MB-COMT AND S-COMT PROMOTERS), AND CYTOKINE EXPRESSION (TNF-ALPHA, IFN-GAMMA, IL-6, AND TGF-BETA). RESULTS: COMT HAPLOTYPES WERE ASSOCIATED WITH DNA METHYLATION IN THE S-COMT PROMOTER, TGF-BETA EXPRESSION, AND SYMPTOMS. HOWEVER, THIS WAS NOT SPECIFIC FOR ONE CONDITION. SIGNIFICANT BETWEEN-GROUP DIFFERENCES WERE FOUND FOR INCREASED DNA METHYLATION IN THE MB-COMT PROMOTER AND DECREASED IFN-GAMMA EXPRESSION IN PATIENTS. DISCUSSION: OUR RESULTS ARE CONSISTENT WITH BASIC AND CLINICAL RESEARCH, PROVIDING INTERESTING INSIGHTS INTO GENETIC-EPIGENETIC REGULATORY MECHANISMS. MB-COMT DNA METHYLATION MIGHT BE AN INDEPENDENT FACTOR CONTRIBUTING TO THE PATHOPHYSIOLOGY OF CFS/FM. FURTHER RESEARCH ON DNA METHYLATION IN COMPLEX CONDITIONS SUCH AS CFS/FM IS WARRANTED. WE RECOMMEND FUTURE RESEARCH TO EMPLOY A REPEATED-MEASURE DESIGN TO CONTROL FOR BIOMARKERS VARIABILITY AND WITHIN-SUBJECT CHANGES. 2022 5 4736 32 NOVEL EPIGENETIC BIOMARKERS MEDIATING BISPHENOL A EXPOSURE AND METABOLIC PHENOTYPES IN FEMALE MICE. THERE IS COMPELLING EVIDENCE THAT EPIGENETIC MODIFICATIONS LINK DEVELOPMENTAL ENVIRONMENTAL INSULTS TO ADULT DISEASE SUSCEPTIBILITY. ANIMAL STUDIES HAVE ASSOCIATED PERINATAL BISPHENOL A (BPA) EXPOSURE TO ALTERED DNA METHYLATION, BUT THESE STUDIES ARE OFTEN LIMITED TO CANDIDATE GENE AND GLOBAL NON-LOCI-SPECIFIC APPROACHES. BY USING AN EPIGENOME-WIDE DISCOVERY PLATFORM, WE ELUCIDATED EPIGENETIC ALTERATIONS IN LIVER TISSUE FROM ADULT MICE OFFSPRING (10 MONTHS) FOLLOWING PERINATAL BPA EXPOSURE AT HUMAN PHYSIOLOGICALLY RELEVANT DOSES (50-NG, 50-MUG, AND 50-MG BPA/KG DIET). BIOLOGICAL PATHWAY ANALYSIS IDENTIFIED AN ENRICHMENT OF SIGNIFICANT DIFFERENTIALLY METHYLATED REGIONS IN METABOLIC PATHWAYS AMONG FEMALES. FURTHERMORE, THROUGH THE USE OF TOP ENRICHED BIOLOGICAL PATHWAYS, 4 CANDIDATE GENES WERE CHOSEN TO ASSESS DNA METHYLATION AS A MEDIATING FACTOR LINKING THE ASSOCIATION OF PERINATAL BPA EXPOSURE TO METABOLIC PHENOTYPES PREVIOUSLY OBSERVED IN FEMALE OFFSPRING. DNA METHYLATION STATUS AT JANUS KINASE-2 (JAK-2), RETINOID X RECEPTOR (RXR), REGULATORY FACTOR X-ASSOCIATED PROTEIN (RFXAP), AND TRANSMEMBRANE PROTEIN 238 (TMEM238) WAS USED WITHIN A MEDIATIONAL REGRESSION ANALYSIS. DNA METHYLATION IN ALL FOUR OF THE CANDIDATE GENES WAS IDENTIFIED AS A MEDIATOR IN THE MECHANISTIC PATHWAY OF DEVELOPMENTAL BPA EXPOSURE AND FEMALE-SPECIFIC ENERGY EXPENDITURE, BODY WEIGHT, AND BODY FAT PHENOTYPES. DATA GENERATED FROM THIS STUDY ARE CRUCIAL FOR DECIPHERING THE MECHANISTIC ROLE OF EPIGENETICS IN THE PATHOGENESIS OF CHRONIC DISEASE AND THE DEVELOPMENT OF EPIGENETIC-BASED PREVENTION AND THERAPEUTIC STRATEGIES FOR COMPLEX HUMAN DISEASE. 2017 6 6190 32 THE IMPACT OF METHYLATION QUANTITATIVE TRAIT LOCI (MQTLS) ON ACTIVE SMOKING-RELATED DNA METHYLATION CHANGES. BACKGROUND: METHYLATION QUANTITATIVE TRAIT LOCI (MQTLS) ARE THE GENETIC VARIANTS THAT MAY AFFECT THE DNA METHYLATION PATTERNS OF CPG SITES. HOWEVER, THEIR ROLES IN INFLUENCING THE DISTURBANCES OF SMOKING-RELATED EPIGENETIC CHANGES HAVE NOT BEEN WELL ESTABLISHED. THIS STUDY WAS CONDUCTED TO ADDRESS WHETHER MQTLS EXIST IN THE VICINITY OF SMOKING-RELATED CPG SITES (+/- 50 KB) AND TO EXAMINE THEIR ASSOCIATIONS WITH SMOKING EXPOSURE AND ALL-CAUSE MORTALITY IN OLDER ADULTS. RESULTS: WE OBTAINED DNA METHYLATION PROFILES IN WHOLE BLOOD SAMPLES BY ILLUMINA INFINIUM HUMAN METHYLATION 450 BEADCHIP ARRAY OF TWO INDEPENDENT SUBSAMPLES OF THE ESTHER STUDY (DISCOVERY SET, N = 581; VALIDATION SET, N = 368) AND THEIR CORRESPONDING GENOTYPING DATA USING THE ILLUMINA INFINIUM ONCOARRAY BEADCHIP. AFTER CORRECTION FOR MULTIPLE TESTING (FDR), WE SUCCESSFULLY IDENTIFIED THAT 70 OUT OF 151 PREVIOUSLY REPORTED SMOKING-RELATED CPG SITES WERE SIGNIFICANTLY ASSOCIATED WITH 192 SNPS WITHIN THE 50 KB SEARCH WINDOW OF EACH LOCUS. THE 192 MQTLS SIGNIFICANTLY INFLUENCED THE ACTIVE SMOKING-RELATED DNA METHYLATION CHANGES, WITH PERCENTAGE CHANGES RANGING FROM 0.01 TO 18.96%, ESPECIALLY FOR THE WEAKLY/MODERATELY SMOKING-RELATED CPG SITES. HOWEVER, THESE IDENTIFIED MQTLS WERE NOT DIRECTLY ASSOCIATED WITH ACTIVE SMOKING EXPOSURE OR ALL-CAUSE MORTALITY. CONCLUSIONS: OUR FINDINGS CLEARLY DEMONSTRATED THAT IF NOT DEALT WITH PROPERLY, THE MQTLS MIGHT IMPAIR THE POWER OF EPIGENETIC-BASED MODELS OF SMOKING EXPOSURE TO A CERTAIN EXTENT. IN ADDITION, SUCH GENETIC VARIANTS COULD BE THE KEY FACTOR TO DISTINGUISH BETWEEN THE HERITABLE AND SMOKING-INDUCED IMPACT ON EPIGENOME DISPARITIES. THESE MQTLS ARE OF SPECIAL IMPORTANCE WHEN DNA METHYLATION MARKERS MEASURED BY ILLUMINA INFINIUM ASSAY ARE USED FOR ANY COMPARATIVE POPULATION STUDIES RELATED TO SMOKING-RELATED CANCERS AND CHRONIC DISEASES. 2017 7 1607 28 DNA METHYLATION, COLON CANCER AND MEDITERRANEAN DIET: RESULTS FROM THE EPIC-ITALY COHORT. THE BIOLOGICAL MECHANISMS THROUGH WHICH ADHERENCE TO MEDITERRANEAN DIET (MD) PROTECTS AGAINST COLON CANCER (CC) ARE POORLY UNDERSTOOD. EVIDENCE SUGGESTS THAT CHRONIC INFLAMMATION MAY BE IMPLICATED IN THE PATHWAY. BOTH DIET AND CC ARE RELATED TO EPIGENETIC REGULATION. WE PERFORMED A NESTED CASE-CONTROL STUDY ON 161 PAIRS FROM THE ITALIAN COMPONENT OF THE EUROPEAN PROSPECTIVE INVESTIGATION INTO CANCER AND NUTRITION (EPIC) COHORT, IN WHICH WE LOOKED FOR THE METHYLATION SIGNALS IN DNA EXTRACTED FROM LEUCOCYTES ASSOCIATED WITH BOTH CC AND MD IN 995 CPGS LOCATED IN 48 INFLAMMATION GENES. THE DNA METHYLATION SIGNALS DETECTED IN THIS ANALYSIS WERE VALIDATED IN A SUBGROUP OF 47 CASE-CONTROL PAIRS AND FURTHER REPLICATED (WHERE VALIDATED) IN 95 NEW PAIRS BY MEANS OF PYROSEQUENCING. AMONG THE CPG SITES SELECTED A-PRIORI IN INFLAMMATION-RELATED GENES, SEVEN CPG SITES WERE FOUND TO BE ASSOCIATED WITH CC STATUS AND WITH MD, IN LINE WITH ITS PROTECTIVE EFFECT. ONLY TWO CPG SITES (CG17968347-SERPINE1 AND CG20674490-RUNX3) WERE VALIDATED USING BISULPHITE PYROSEQUENCING AND, AFTER REPLICATION, WE FOUND THAT DNA METHYLATION OF CG20674490-RUNX3 MAY BE A POTENTIAL MOLECULAR MEDIATOR EXPLAINING THE PROTECTIVE EFFECT OF MD ON CC ONSET. THE USE OF A 'MEET-IN-THE-MIDDLE' APPROACH TO IDENTIFY THE OVERLAP BETWEEN EXPOSURE AND PREDICTIVE MARKERS OF DISEASE IS INNOVATIVE IN STUDIES ON THE RELATIONSHIP BETWEEN DIET AND CANCER, IN WHICH EXPOSURE ASSESSMENT IS DIFFICULT AND THE MECHANISMS THROUGH WHICH THE NUTRIENTS EXERT THEIR PROTECTIVE EFFECT IS LARGELY UNKNOWN. 2019 8 686 18 BRAIN-SPECIFIC GENES CONTRIBUTE TO CHRONIC BUT NOT TO ACUTE BACK PAIN. INTRODUCTION: BACK PAIN IS THE LEADING CAUSE OF DISABILITY WORLDWIDE. ALTHOUGH MOST BACK PAIN CASES ARE ACUTE, 20% OF ACUTE PAIN PATIENTS EXPERIENCE CHRONIC BACK PAIN SYMPTOMS. IT IS UNCLEAR WHETHER ACUTE PAIN AND CHRONIC PAIN HAVE SIMILAR OR DISTINCT UNDERLYING GENETIC MECHANISMS. OBJECTIVES: TO CHARACTERIZE THE MOLECULAR AND CELLULAR PATHWAYS CONTRIBUTING TO ACUTE AND CHRONIC PAIN STATES. METHODS: CROSS-SECTIONAL OBSERVATIONAL GENOME-WIDE ASSOCIATION STUDY. RESULTS: A TOTAL OF 375,158 INDIVIDUALS FROM THE UK BIOBANK COHORT WERE INCLUDED IN THE DISCOVERY OF GENOME-WIDE ASSOCIATION STUDY. OF THOSE, 70,633 (19%) AND 32,209 (9%) INDIVIDUALS MET THE DEFINITION OF CHRONIC AND ACUTE BACK PAIN, RESPECTIVELY. A TOTAL OF 355 SINGLE NUCLEOTIDE POLYMORPHISM GROUPED INTO 13 LOCI REACHED THE GENOME-WIDE SIGNIFICANCE THRESHOLD (5X10(-8)) FOR CHRONIC BACK PAIN, BUT NONE FOR ACUTE. OF THESE, 7 LOCI WERE REPLICATED IN THE NORD-TRONDELAG HEALTH STUDY (HUNT) COHORT (19,760 CHRONIC LOW BACK PAIN CASES AND 28,674 PAIN-FREE CONTROLS). SINGLE NUCLEOTIDE POLYMORPHISM HERITABILITY WAS 4.6% (P=1.4X10(-78)) FOR CHRONIC BACK PAIN AND 0.81% (P=1.4X10-8) FOR ACUTE BACK PAIN. SIMILAR DIFFERENCES IN HERITABILITY ESTIMATES BETWEEN ACUTE AND CHRONIC BACK PAIN WERE FOUND IN THE HUNT COHORT: 3.4% (P=0.0011) AND 0.6% (P=0.851), RESPECTIVELY. PATHWAY ANALYSES, TISSUE-SPECIFIC HERITABILITY ENRICHMENT ANALYSES, AND EPIGENETIC CHARACTERIZATION SUGGEST A SUBSTANTIAL GENETIC CONTRIBUTION TO CHRONIC BUT NOT ACUTE BACK PAIN FROM THE LOCI PREDOMINANTLY EXPRESSED IN THE CENTRAL NERVOUS SYSTEM. CONCLUSION: CHRONIC BACK PAIN IS SUBSTANTIALLY MORE HERITABLE THAN ACUTE BACK PAIN. THIS HERITABILITY IS MOSTLY ATTRIBUTED TO GENES EXPRESSED IN THE BRAIN. 2022 9 4750 26 NOVEL REGIONAL AGE-ASSOCIATED DNA METHYLATION CHANGES WITHIN HUMAN COMMON DISEASE-ASSOCIATED LOCI. BACKGROUND: ADVANCING AGE PROGRESSIVELY IMPACTS ON RISK AND SEVERITY OF CHRONIC DISEASE. IT ALSO MODIFIES THE EPIGENOME, WITH CHANGES IN DNA METHYLATION, DUE TO BOTH RANDOM DRIFT AND VARIATION WITHIN SPECIFIC FUNCTIONAL LOCI. RESULTS: IN A DISCOVERY SET OF 2238 PERIPHERAL-BLOOD GENOME-WIDE DNA METHYLOMES AGED 19-82 YEARS, WE IDENTIFY 71 AGE-ASSOCIATED DIFFERENTIALLY METHYLATED REGIONS WITHIN THE LINKAGE DISEQUILIBRIUM BLOCKS OF THE SINGLE NUCLEOTIDE POLYMORPHISMS FROM THE NIH GENOME-WIDE ASSOCIATION STUDY CATALOGUE. THIS INCLUDED 52 NOVEL REGIONS, 29 WITHIN LOCI NOT COVERED BY 450 K OR 27 K ILLUMINA ARRAY, AND WITH ENRICHMENT FOR DNASE-I HYPERSENSITIVITY SITES ACROSS THE FULL RANGE OF TISSUES. THESE AGE-ASSOCIATED DIFFERENTIALLY METHYLATED REGIONS ALSO SHOW MARKED ENRICHMENT FOR ENHANCERS AND POISED PROMOTERS ACROSS MULTIPLE CELL TYPES. IN A REPLICATION SET OF 2084 DNA METHYLOMES, 95.7 % OF THE AGE-ASSOCIATED DIFFERENTIALLY METHYLATED REGIONS SHOWED THE SAME DIRECTION OF AGEING EFFECT, WITH 80.3 % AND 53.5 % REPLICATED TO P < 0.05 AND P < 1.85 X 10(-8), RESPECTIVELY. CONCLUSION: BY ANALYSING THE FUNCTIONALLY ENRICHED DISEASE AND TRAIT-ASSOCIATED REGIONS OF THE HUMAN GENOME, WE IDENTIFY NOVEL EPIGENETIC AGEING CHANGES, WHICH COULD BE USEFUL BIOMARKERS OR PROVIDE MECHANISTIC INSIGHTS INTO AGE-RELATED COMMON DISEASES. 2016 10 1598 25 DNA METHYLATION SIGNATURE IN MONONUCLEAR CELLS AND PROINFLAMMATORY CYTOKINES MAY DEFINE MOLECULAR SUBTYPES IN SPORADIC MENIERE DISEASE. MENIERE DISEASE (MD) IS A MULTIFACTORIAL DISORDER OF THE INNER EAR CHARACTERIZED BY VERTIGO ATTACKS ASSOCIATED WITH SENSORINEURAL HEARING LOSS AND TINNITUS WITH A SIGNIFICANT HERITABILITY. ALTHOUGH MD HAS BEEN ASSOCIATED WITH SEVERAL GENES, NO EPIGENETIC STUDIES HAVE BEEN PERFORMED ON MD. HERE WE PERFORMED WHOLE-GENOME BISULFITE SEQUENCING IN 14 MD PATIENTS AND SIX HEALTHY CONTROLS, WITH THE AIM OF IDENTIFYING AN MD METHYLATION SIGNATURE AND POTENTIAL DISEASE MECHANISMS. WE OBSERVED A HIGH NUMBER OF DIFFERENTIALLY METHYLATED CPGS (DMC) WHEN COMPARING MD PATIENTS TO CONTROLS (N= 9545), SEVERAL OF THEM IN HEARING LOSS GENES, SUCH AS PCDH15,&NBSP;ADGRV1 AND CDH23. BIOINFORMATIC ANALYSES OF DMCS AND CIS-REGULATORY REGIONS PREDICTED PHENOTYPES RELATED TO ABNORMAL EXCITATORY POSTSYNAPTIC CURRENTS, ABNORMAL NMDA-MEDIATED RECEPTOR CURRENTS AND ABNORMAL GLUTAMATE-MEDIATED RECEPTOR CURRENTS WHEN COMPARING MD TO CONTROLS. MOREOVER, WE IDENTIFIED VARIOUS DMCS IN GENES PREVIOUSLY ASSOCIATED WITH COCHLEOVESTIBULAR PHENOTYPES IN MICE. WE HAVE ALSO FOUND 12 UNDERMETHYLATED REGIONS (UMR) THAT WERE EXCLUSIVE TO MD, INCLUDING TWO UMR IN AN INTER CPG ISLAND IN THE PHB GENE. WE SUGGEST THAT THE DNA METHYLATION SIGNATURE ALLOWS DISTINGUISHING BETWEEN MD PATIENTS AND CONTROLS. THE ENRICHMENT ANALYSIS CONFIRMS PREVIOUS FINDINGS OF A CHRONIC INFLAMMATORY PROCESS UNDERLYING MD. 2021 11 5887 32 SYSTEMIC STEROID EXPOSURE IS ASSOCIATED WITH DIFFERENTIAL METHYLATION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE. RATIONALE: SYSTEMIC GLUCOCORTICOIDS ARE USED THERAPEUTICALLY TO TREAT A VARIETY OF MEDICAL CONDITIONS. EPIGENETIC PROCESSES SUCH AS DNA METHYLATION MAY REFLECT EXPOSURE TO GLUCOCORTICOIDS AND MAY BE INVOLVED IN MEDIATING THE RESPONSES AND SIDE EFFECTS ASSOCIATED WITH THESE MEDICATIONS. OBJECTIVES: TO TEST THE HYPOTHESIS THAT DIFFERENCES IN DNA METHYLATION ARE ASSOCIATED WITH CURRENT SYSTEMIC STEROID USE. METHODS: WE OBTAINED DNA METHYLATION DATA AT 27,578 CPG SITES IN 14,475 GENES THROUGHOUT THE GENOME IN TWO LARGE, INDEPENDENT COHORTS: THE INTERNATIONAL COPD GENETICS NETWORK (N(DISCOVERY) = 1,085) AND THE BOSTON EARLY ONSET COPD STUDY (N(REPLICATION) = 369). SITES WERE TESTED FOR ASSOCIATION WITH CURRENT SYSTEMIC STEROID USE USING GENERALIZED LINEAR MIXED MODELS. MEASUREMENTS AND MAIN RESULTS: A TOTAL OF 511 SITES DEMONSTRATED SIGNIFICANT DIFFERENTIAL METHYLATION BY SYSTEMIC CORTICOSTEROID USE IN ALL THREE OF OUR PRIMARY MODELS. PYROSEQUENCING VALIDATION CONFIRMED ROBUST DIFFERENTIAL METHYLATION AT CPG SITES ANNOTATED TO GENES SUCH AS SLC22A18, LRP3, HIPK3, SCNN1A, FXYD1, IRF7, AZU1, SIT1, GPR97, ABHD16B, AND RABGEF1. FUNCTIONAL ANNOTATION CLUSTERING DEMONSTRATED SIGNIFICANT ENRICHMENT IN INTRINSIC MEMBRANE COMPONENTS, HEMOSTASIS AND COAGULATION, CELLULAR ION HOMEOSTASIS, LEUKOCYTE AND LYMPHOCYTE ACTIVATION AND CHEMOTAXIS, PROTEIN TRANSPORT, AND RESPONSES TO NUTRIENTS. CONCLUSIONS: OUR ANALYSES SUGGEST THAT SYSTEMIC STEROID USE IS ASSOCIATED WITH SITE-SPECIFIC DIFFERENTIAL METHYLATION THROUGHOUT THE GENOME. DIFFERENTIALLY METHYLATED CPG SITES WERE FOUND IN BIOLOGICALLY PLAUSIBLE AND PREVIOUSLY UNSUSPECTED PATHWAYS; THESE GENES AND PATHWAYS MAY BE RELEVANT IN THE DEVELOPMENT OF NOVEL TARGETED THERAPIES. 2012 12 6826 32 [GENOME-WIDE ANALYSIS OF DNA METHYLATION IN CD4+ T LYMPHOCYTES OF PATIENTS WITH PRIMARY PROGRESSIVE MULTIPLE SCLEROSIS INDICATES INVOLVEMENT OF THIS EPIGENETIC PROCESS IN THE DISEASE IMMUNOPATHOGENESIS]. THE PATHOGENESIS OF MULTIPLE SCLEROSIS (MS), A CHRONIC DISEASE OF THE CNS, INCLUDES AUTOIMMUNE AND NEURODEGENERATIVE COMPONENTS. IN MOST CASES, PATIENTS DEVELOP RELAPSING-REMITTING MS (RRMS), WHILE 10-15% OF PATIENTS DEVELOP PRIMARY PROGRESSIVE MS (PPMS), WHICH DIFFERS FROM RRMS IN THE MECHANISMS OF THE PATHOLOGICAL PROCESS, SOME DEMOGRAPHIC, AND SOME CLINICAL CHARACTERISTICS. THESE DIFFERENCES MAY BE EXPLAINED BY THE EPIGENETIC REGULATION OF GENE EXPRESSION IN PPMS INCLUDING DNA METHYLATION AS ONE OF THE KEY EPIGENETIC PROCESSES. THE FEATURES OF DNA METHYLATION IN VARIOUS CELL POPULATIONS IN PPMS PATIENTS REMAIN UNDERSTUDIED. THE GOAL OF THIS STUDY IS TO IDENTIFY DIFFERENTIALLY METHYLATED CPG SITES (DMSS) OF THE GENOME OF CD4+ T LYMPHOCYTES, WHICH CHARACTERIZE PPMS. THE STUDY INCLUDED EIGHT TREATMENT-NAIVE PPMS PATIENTS AND EIGHT HEALTHY CONTROLS. GENOME-WIDE ANALYSIS OF DNA METHYLATION OF CD4+ T LYMPHOCYTES WAS PERFORMED USING HIGH-DENSITY DNA MICROARRAYS. WE HAVE IDENTIFIED 108 DMSS, WHICH DISTINGUISH PPMS PATIENTS FROM HEALTHY CONTROLS. IN PPMS PATIENTS 81% OF THE DMSS ARE HYPERMETHYLATED. MORE THAN A HALF OF THE IDENTIFIED DMSS ARE LOCATED IN KNOWN GENES IN CPG ISLANDS AND ADJACENT REGIONS, WHICH INDICATES A HIGH FUNCTIONAL SIGNIFICANCE OF THESE DMSS IN PPMS DEVELOPMENT. ANALYSIS OF THE OVERREPRESENTATION OF DMS-CONTAINING GENES IN THE MAIN BIOLOGICAL PROCESSES DEMONSTRATES THEIR INVOLVEMENT IN THE REGULATION OF CELL ADHESION TO THE EXTRACELLULAR MATRIX AND THE DEVELOPMENT OF THE IMMUNE RESPONSE, I.E., ANTIGEN PROCESSING AND PRESENTATION, AND DEVELOPMENT OF THE IMMUNE SYSTEM. GENOME-WIDE ANALYSIS OF DNA METHYLATION IN CD4+ T LYMPHOCYTES OF PPMS PATIENTS INDICATES THE INVOLVEMENT OF THIS EPIGENETIC PROCESS IN THE IMMUNOPATHOGENESIS OF THE DISEASE. THESE RESULTS MAY HELP BETTER UNDERSTAND THE PATHOGENESIS OF THIS SEVERE FORM OF MS. 2022 13 546 26 ATTENUATED EXPRESSION OF SLCO2A1 CAUSED BY DNA METHYLATION IN PEDIATRIC INFLAMMATORY BOWEL DISEASE. BACKGROUND: SLCO2A1 ENCODES A PROSTAGLANDIN (PG) TRANSPORTER, AND AUTOSOMAL RECESSIVE PATHOGENIC VARIANTS OF THIS GENE CAUSE CHRONIC ENTEROPATHY ASSOCIATED WITH SLCO2A1. IT IS UNCLEAR WHETHER A HETEROZYGOUS PATHOGENIC VARIANT OF SLCO2A1 HAS A ROLE IN THE PATHOGENESIS OF OTHER TYPES OF INFLAMMATORY BOWEL DISEASE (IBD). IN THIS STUDY, WE INVESTIGATED THE POSSIBLE INVOLVEMENT OF A LOCAL EPIGENETIC ALTERATION IN SLCO2A1 IN PATIENTS WITH A HETEROZYGOUS PATHOGENIC VARIANT. METHODS: WE CONDUCTED WHOLE-EXOME SEQUENCING OF SAMPLES FROM 2 SISTERS WITH SUSPECTED MONOGENIC IBD. IN ADDITION, WE PERFORMED BISULFITE SEQUENCING USING DNA EXTRACTED FROM THEIR SMALL AND LARGE INTESTINE SAMPLES TO EXPLORE EPIGENETIC ALTERATIONS. RESULTS: A HETEROZYGOUS SPLICING SITE VARIANT, SLCO2A1:C.940 + 1G > A, WAS DETECTED IN BOTH PATIENTS. TO EXPLORE THE POSSIBLE INVOLVEMENT OF EPIGENETIC ALTERATIONS, WE ANALYZED PROTEIN AND MESSENGER RNA EXPRESSION OF SLCO2A1, AND OBSERVED ATTENUATED SLCO2A1 EXPRESSION IN THE INFLAMED LESIONS OF THESE PATIENTS COMPARED WITH THAT IN THE CONTROL INDIVIDUALS. FURTHERMORE, BISULFITE SEQUENCING INDICATED DENSE METHYLATION IN THE PROMOTER REGION OF SLCO2A1 ONLY IN THE INFLAMED LESIONS OF BOTH PATIENTS. THE URINARY PG METABOLITE LEVELS IN THESE PATIENTS WERE COMPARABLE TO THOSE IN PATIENTS WITH CHRONIC ENTEROPATHY ASSOCIATED WITH SLCO2A1 AND HIGHER THAN THOSE IN THE CONTROL INDIVIDUALS. WE FOUND CONSIDERABLY HIGHER LEVELS OF THE METABOLITES IN PATIENT 1, WHO SHOWED MORE SEVERE SYMPTOMS THAN PATIENT 2. CONCLUSIONS: LOCAL DNA METHYLATION ATTENUATED SLCO2A1 EXPRESSION, WHICH MAY EVOKE LOCAL INFLAMMATION OF THE MUCOSA BY THE UNINCORPORATED PG. THESE FINDINGS MAY IMPROVE OUR UNDERSTANDING OF THE EPIGENETIC MECHANISMS UNDERLYING IBD DEVELOPMENT. 2023 14 1529 29 DNA METHYLATION CHANGES IN WHOLE BLOOD AND CD16+ NEUTROPHILS IN RESPONSE TO CHRONIC FOLIC ACID SUPPLEMENTATION IN WOMEN OF CHILDBEARING AGE. FOLATE, A WATER-SOLUBLE VITAMIN, IS A KEY SOURCE OF ONE-CARBON GROUPS FOR DNA METHYLATION, BUT STUDIES OF THE DNA METHYLATION RESPONSE TO SUPPLEMENTAL FOLIC ACID YIELD INCONSISTENT RESULTS. THESE STUDIES ARE COMMONLY CONDUCTED USING WHOLE BLOOD, WHICH CONTAINS A MIXED POPULATION OF WHITE BLOOD CELLS THAT HAVE BEEN SHOWN TO CONFOUND RESULTS. THE OBJECTIVE OF THIS STUDY WAS TO DETERMINE IF CD16+ NEUTROPHILS MAY PROVIDE MORE SPECIFIC DATA THAN WHOLE BLOOD FOR IDENTIFYING DNA METHYLATION RESPONSE TO CHRONIC FOLIC ACID SUPPLEMENTATION. THE STUDY WAS PERFORMED IN NORMAL WEIGHT (BMI 18.5 - 24.9 KG/M2) WOMEN (18 - 35 Y; N = 12), WITH BLOOD SAMPLES TAKEN BEFORE AND AFTER 8 WEEKS OF FOLIC ACID SUPPLEMENTATION AT 800 MUG/DAY. DNA METHYLATION PATTERNS FROM WHOLE BLOOD AND ISOLATED CD16+ NEUTROPHILS WERE MEASURED ACROSS >485,000 CPG SITES THROUGHOUT THE GENOME USING THE INFINIUM HUMANMETHYLATION450 BEADCHIP. OVER THE COURSE OF THE 8-WEEK SUPPLEMENTATION, 6746 AND 7513 CPG SITES CHANGED (P < 0.05) IN WHOLE BLOOD AND CD16+ NEUTROPHILS, RESPECTIVELY. DNA METHYLATION DECREASED IN 68.4% (WHOLE BLOOD) AND 71.8% (CD16+ NEUTROPHILS) OF THESE SITES. THERE WERE ONLY 182 CPG SITES THAT CHANGED IN BOTH THE WHOLE BLOOD AND CD16+ NEUTROPHILS, 139 OF WHICH CHANGED IN THE SAME DIRECTION. THESE RESULTS SUGGEST THAT THE GENOME-WIDE DNA METHYLATION RESPONSE TO CHRONIC FOLIC ACID SUPPLEMENTATION IS DIFFERENT BETWEEN WHOLE BLOOD AND CD16+ NEUTROPHILS AND THAT A SINGLE WHITE BLOOD CELL TYPE MAY FUNCTION AS A MORE SPECIFIC EPIGENETIC REPORTER OF FOLATE STATUS THAN WHOLE BLOOD. 2017 15 5464 21 RESILIENCE IN LONG-TERM VIRAL INFECTION: GENETIC DETERMINANTS AND INTERACTIONS. VIRUS-INDUCED NEUROLOGICAL SEQUELAE RESULTING FROM INFECTION BY THEILER'S MURINE ENCEPHALOMYELITIS VIRUS (TMEV) ARE USED FOR STUDYING HUMAN CONDITIONS RANGING FROM EPILEPTIC SEIZURES TO DEMYELINATING DISEASE. MOUSE STRAINS ARE TYPICALLY CONSIDERED SUSCEPTIBLE OR RESISTANT TO TMEV INFECTION BASED ON VIRAL PERSISTENCE AND EXTREME PHENOTYPES, SUCH AS DEMYELINATION. WE HAVE IDENTIFIED A BROADER SPECTRUM OF PHENOTYPIC OUTCOMES BY INFECTING STRAINS OF THE GENETICALLY DIVERSE COLLABORATIVE CROSS (CC) MOUSE RESOURCE. WE EVALUATED THE CHRONIC-INFECTION GENE EXPRESSION PROFILES OF HIPPOCAMPI AND THORACIC SPINAL CORDS FOR 19 CC STRAINS IN RELATION TO PHENOTYPIC SEVERITY AND TMEV PERSISTENCE. STRAINS WERE CLUSTERED BASED ON SIMILAR PHENOTYPIC PROFILES AND TMEV LEVELS AT 90 DAYS POST-INFECTION, AND WE CATEGORIZED DISTINCT TMEV RESPONSE PROFILES. THE THREE MOST COMMON PROFILES INCLUDED "RESISTANT" AND "SUSCEPTIBLE," AS BEFORE, AS WELL AS A "RESILIENT" TMEV RESPONSE GROUP WHICH EXPERIENCED BOTH TMEV PERSISTENCE AND MILD NEUROLOGICAL PHENOTYPES EVEN AT 90 DAYS POST-INFECTION. EACH PROFILE HAD A DISTINCT GENE EXPRESSION SIGNATURE, ALLOWING THE IDENTIFICATION OF PATHWAYS AND NETWORKS SPECIFIC TO EACH TMEV RESPONSE GROUP. CC FOUNDER HAPLOTYPES FOR GENES INVOLVED IN THESE PATHWAYS/NETWORKS REVEALED CANDIDATE RESPONSE-SPECIFIC ALLELES. THESE ALLELES DEMONSTRATED PLEIOTROPY AND EPIGENETIC (MIRNA) REGULATION IN LONG-TERM TMEV INFECTION, WITH PARTICULAR RELEVANCE FOR RESILIENT MOUSE STRAINS. 2021 16 6911 21 [TWO GERMAN BIRTH COHORTS: GINIPLUS AND LISAPLUS]. NUMEROUS CHRONIC DISEASES IN CHILDHOOD AND ADULTHOOD HAVE THEIR ORIGINS IN PERINATAL LIFE AND ARE POTENTIALLY INFLUENCED BY TRANS-GENERATIONAL EPIGENETIC PROCESSES. THEREFORE, PROSPECTIVE BIRTH COHORTS CAN SUBSTANTIALLY CONTRIBUTE TO OUR KNOWLEDGE ABOUT THE ETIOLOGY OF DISEASES INCLUDING MODIFIABLE RISK FACTORS. THE TWO POPULATION-BASED GERMAN BIRTH COHORTS GINIPLUS AND LISAPLUS AIM TO DESCRIBE THE NATURAL COURSE OF CHRONIC DISEASES AND INTERMEDIATE PHENOTYPES IN CHILDHOOD AND ITS DETERMINANTS, AND TO IDENTIFY POTENTIAL GENETIC EFFECT MODIFICATIONS. IN THE MID-1990S, 5,991 (GINIPLUS) AND 3,097 (LISAPLUS) HEALTHY, TERM NEWBORNS WERE RECRUITED FOR LONG-TERM FOLLOW-UP IN FOUR REGIONS OF GERMANY. THE FOLLOW-UP RATE FOR THE FIRST 10 YEARS WAS ABOUT 55%. WE ANALYZED THE GROWTH AND DEVELOPMENT OF OVERWEIGHT, INFECTIONS AND ALLERGIC DISEASES, MENTAL AND ORAL HEALTH, METABOLIC AND INFLAMMATORY PARAMETERS AND THE ROLE OF POTENTIAL RISK FACTORS INCLUDING GENETICS. THE RESULTS OF THESE TWO BIRTH COHORTS SUBSTANTIALLY CONTRIBUTE TO THE CURRENT KNOWLEDGE ABOUT THE NATURAL COURSE OF THESE HEALTH PARAMETERS. THESE DATA WERE INCLUDED IN MANY INTERNATIONAL PROJECTS AND CONSORTIA FOR PURPOSES OF INTERNATIONAL COMPARISONS OF PREVALENCE AND CONSISTENCY OF FINDINGS, AND TO INCREASE THE POWER OF THE ANALYSES. 2012 17 1990 30 EPIGENETIC ANALYSIS OF PAGET'S DISEASE OF BONE IDENTIFIES DIFFERENTIALLY METHYLATED LOCI THAT PREDICT DISEASE STATUS. PAGET'S DISEASE OF BONE (PDB) IS CHARACTERIZED BY FOCAL INCREASES IN DISORGANIZED BONE REMODELING. THIS STUDY AIMS TO CHARACTERIZE PDB-ASSOCIATED CHANGES IN DNA METHYLATION PROFILES IN PATIENTS' BLOOD. META-ANALYSIS OF DATA FROM THE DISCOVERY AND CROSS-VALIDATION SET, EACH COMPRISING 116 PDB CASES AND 130 CONTROLS, REVEALED SIGNIFICANT DIFFERENCES IN DNA METHYLATION AT 14 CPG SITES, 4 CPG ISLANDS, AND 6 GENE-BODY REGIONS. THESE LOCI, INCLUDING TWO CHARACTERIZED AS FUNCTIONAL THROUGH EXPRESSION QUANTITATIVE TRAIT-METHYLATION ANALYSIS, WERE ASSOCIATED WITH FUNCTIONS RELATED TO OSTEOCLAST DIFFERENTIATION, MECHANICAL LOADING, IMMUNE FUNCTION, AND VIRAL INFECTION. A MULTIVARIATE CLASSIFIER BASED ON DISCOVERY SAMPLES WAS FOUND TO DISCRIMINATE PDB CASES AND CONTROLS FROM THE CROSS-VALIDATION WITH A SENSITIVITY OF 0.84, SPECIFICITY OF 0.81, AND AN AREA UNDER CURVE OF 92.8%. IN CONCLUSION, THIS STUDY HAS SHOWN FOR THE FIRST TIME THAT EPIGENETIC FACTORS CONTRIBUTE TO THE PATHOGENESIS OF PDB AND MAY OFFER DIAGNOSTIC MARKERS FOR PREDICTION OF THE DISEASE. 2021 18 177 26 ACCELERATED EPIGENETIC AGING AND INFLAMMATORY/IMMUNOLOGICAL PROFILE (IPAGE) IN PATIENTS WITH CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IS DEFINED BY A REDUCED ESTIMATED GLOMERULAR FILTRATION RATE (EGFR). THIS FAILURE CAN BE RELATED TO A PHENOTYPE OF ACCELERATED AGING. IN THIS WORK, WE CONSIDERED 76 PATIENTS WITH END-STAGE RENAL DISEASE (ESRD) AND 83 HEALTHY CONTROLS. WE CONCOMITANTLY EVALUATED FOR THE FIRST TIME TWO MEASURES THAT CAN BE INFORMATIVE OF THE RATE OF AGING, I.E., WHOLE BLOOD DNA METHYLATION USING THE ILLUMINA INFINIUM EPIC ARRAY AND PLASMA LEVELS OF A SELECTION OF INFLAMMATORY/IMMUNOLOGICAL PROTEINS USING MULTIPLEX IMMUNOASSAYS. FIRST OF ALL, WE DEMONSTRATED ACCELERATED AGING IN TERMS OF THE MOST COMMON EPIGENETIC AGE ESTIMATORS IN CKD PATIENTS. MOREOVER, WE DEVELOPED A NEW CLOCK/PREDICTOR OF AGE BASED ON THE INFLAMMATORY/IMMUNOLOGICAL PROFILE (IPAGE) AND IDENTIFIED THE INFLAMMATORY/IMMUNOLOGICAL BIOMARKERS DIFFERENTIALLY EXPRESSED BETWEEN CASES AND CONTROLS. IPAGE APPEARED TO BE MORE SENSITIVE THAN EPIGENETIC CLOCKS IN QUANTIFYING THE ACCELERATED AGING PHENOTYPE OF ESRD PATIENTS. INTERESTINGLY, WE DID NOT FIND ANY CORRELATION BETWEEN THE AGE ACCELERATION EVALUATED ACCORDING TO THE EPIGENETIC CLOCKS AND IPAGE IN EITHER THE ESRD GROUP OR THE CONTROL GROUP. ON THE WHOLE, OUR DATA SHOW A CONSISTENT ACCELERATED AGING PHENOTYPE IN ESRD PATIENTS, WHICH IS BETTER APPRECIATED BY QUANTIFYING THE UNDERLYING INFLAMMATORY PROCESSES (INFLAMMAGING) BY IPAGE THAN BY USING EPIGENETIC CLOCKS. 2022 19 2653 30 EPIGENOTYPING IN PERIPHERAL BLOOD CELL DNA AND BREAST CANCER RISK: A PROOF OF PRINCIPLE STUDY. BACKGROUND: EPIGENETIC CHANGES ARE EMERGING AS ONE OF THE MOST IMPORTANT EVENTS IN CARCINOGENESIS. TWO ALTERATIONS IN THE PATTERN OF DNA METHYLATION IN BREAST CANCER (BC) HAVE BEEN PREVIOUSLY REPORTED; ACTIVE ESTROGEN RECEPTOR-ALPHA (ER-ALPHA) IS ASSOCIATED WITH DECREASED METHYLATION OF ER-ALPHA TARGET (ERT) GENES, AND POLYCOMB GROUP TARGET (PCGT) GENES ARE MORE LIKELY THAN OTHER GENES TO HAVE PROMOTER DNA HYPERMETHYLATION IN CANCER. HOWEVER, WHETHER DNA METHYLATION IN NORMAL UNRELATED CELLS IS ASSOCIATED WITH BC RISK AND WHETHER THESE IMPRINTS CAN BE RELATED TO FACTORS WHICH CAN BE MODIFIED BY THE ENVIRONMENT, IS UNCLEAR. METHODOLOGY/PRINCIPAL FINDINGS: USING QUANTITATIVE METHYLATION ANALYSIS IN A CASE-CONTROL STUDY (N = 1,083) WE FOUND THAT DNA METHYLATION OF PERIPHERAL BLOOD CELL DNA PROVIDES GOOD PREDICTION OF BC RISK. WE ALSO REPORT THAT INVASIVE DUCTAL AND INVASIVE LOBULAR BC IS CHARACTERIZED BY TWO DIFFERENT SETS OF GENES, THE LATTER PARTICULAR BY GENES INVOLVED IN THE DIFFERENTIATION OF THE MESENCHYME (PITX2, TITF1, GDNF AND MYOD1). FINALLY WE DEMONSTRATE THAT ONLY ERT GENES PREDICT ER POSITIVE BC; LACK OF PERIPHERAL BLOOD CELL DNA METHYLATION OF ZNF217 PREDICTED BC INDEPENDENT OF AGE AND FAMILY HISTORY (ODDS RATIO 1.49; 95% CONFIDENCE INTERVAL 1.12-1.97; P = 0.006) AND WAS ASSOCIATED WITH ER-ALPHA BIOACTIVITY IN THE CORRESPONDING SERUM. CONCLUSION/SIGNIFICANCE: THIS FIRST LARGE-SCALE EPIGENOTYPING STUDY DEMONSTRATES THAT DNA METHYLATION MAY SERVE AS A LINK BETWEEN THE ENVIRONMENT AND THE GENOME. FACTORS THAT CAN BE MODULATED BY THE ENVIRONMENT (LIKE ESTROGENS) LEAVE AN IMPRINT IN THE DNA OF CELLS THAT ARE UNRELATED TO THE TARGET ORGAN AND INDICATE THE PREDISPOSITION TO DEVELOP A CANCER. FURTHER RESEARCH WILL NEED TO DEMONSTRATE WHETHER DNA METHYLATION PROFILES WILL BE ABLE TO SERVE AS A NEW TOOL TO PREDICT THE RISK OF DEVELOPING CHRONIC DISEASES WITH SUFFICIENT ACCURACY TO GUIDE PREVENTIVE MEASURES. 2008 20 39 37 A COMPARISON OF EPIGENETIC MITOTIC-LIKE CLOCKS FOR CANCER RISK PREDICTION. BACKGROUND: DNA METHYLATION CHANGES THAT ACCRUE IN THE STEM CELL POOL OF AN ADULT TISSUE IN LINE WITH THE CUMULATIVE NUMBER OF CELL DIVISIONS MAY CONTRIBUTE TO THE OBSERVED VARIATION IN CANCER RISK AMONG TISSUES AND INDIVIDUALS. THUS, THE CONSTRUCTION OF EPIGENETIC "MITOTIC" CLOCKS THAT CAN MEASURE THE LIFETIME NUMBER OF STEM CELL DIVISIONS IS OF PARAMOUNT INTEREST. METHODS: BUILDING UPON A DYNAMIC MODEL OF DNA METHYLATION GAIN IN UNMETHYLATED CPG-RICH REGIONS, WE HERE DERIVE A NOVEL MITOTIC CLOCK ("EPITOC2") THAT CAN DIRECTLY ESTIMATE THE CUMULATIVE NUMBER OF STEM CELL DIVISIONS IN A TISSUE. WE COMPARE EPITOC2 TO A DIFFERENT MITOTIC MODEL, BASED ON HYPOMETHYLATION AT SOLO-WCGW SITES ("HYPOCLOCK"), IN TERMS OF THEIR ABILITY TO MEASURE MITOTIC AGE OF NORMAL ADULT TISSUES AND PREDICT CANCER RISK. RESULTS: USING EPITOC2, WE ESTIMATE THE INTRINSIC STEM CELL DIVISION RATE FOR DIFFERENT NORMAL TISSUE TYPES, DEMONSTRATING EXCELLENT AGREEMENT (PEARSON CORRELATION = 0.92, R(2) = 0.85, P = 3E-6) WITH THOSE DERIVED FROM EXPERIMENT. IN CONTRAST, HYPOCLOCK'S ESTIMATES DO NOT (PEARSON CORRELATION = 0.30, R(2) = 0.09, P = 0.29). WE VALIDATE THESE RESULTS IN INDEPENDENT DATASETS PROFILING NORMAL ADULT TISSUE TYPES. WHILE BOTH EPITOC2 AND HYPOCLOCK CORRECTLY PREDICT AN INCREASED MITOTIC RATE IN CANCER, EPITOC2 IS MORE ROBUST AND SIGNIFICANTLY BETTER AT DISCRIMINATING PRENEOPLASTIC LESIONS CHARACTERIZED BY CHRONIC INFLAMMATION, A MAJOR DRIVER OF TISSUE TURNOVER AND CANCER RISK. OUR DATA SUGGEST THAT DNA METHYLATION LOSS AT SOLO-WCGWS IS SIGNIFICANT ONLY WHEN CELLS ARE UNDER HIGH REPLICATIVE STRESS AND THAT EPITOC2 IS A BETTER MITOTIC AGE AND CANCER RISK PREDICTION MODEL FOR NORMAL ADULT TISSUES. CONCLUSIONS: THESE RESULTS HAVE PROFOUND IMPLICATIONS FOR OUR UNDERSTANDING OF EPIGENETIC CLOCKS AND FOR DEVELOPING CANCER RISK PREDICTION OR EARLY DETECTION ASSAYS. WE PROPOSE THAT MEASUREMENT OF DNAM AT THE 163 EPITOC2 CPGS IN ADULT PRE-NEOPLASTIC LESIONS, AND POTENTIALLY IN SERUM CELL-FREE DNA, COULD PROVIDE THE BASIS FOR BUILDING FEASIBLE PRE-DIAGNOSTIC OR CANCER RISK ASSAYS. EPITOC2 IS FREELY AVAILABLE FROM HTTPS://DOI.ORG/10.5281/ZENODO.2632938. 2020