1 2537 80 EPIGENETICS IN HEART FAILURE PHENOTYPES. CHRONIC HEART FAILURE (HF) IS A LEADING CLINICAL AND PUBLIC PROBLEM POSING A HIGHER RISK OF MORBIDITY AND MORTALITY IN DIFFERENT POPULATIONS. HF APPEARS TO BE IN BOTH PHENOTYPIC FORMS: HF WITH REDUCED LEFT VENTRICULAR EJECTION FRACTION (HFREF) AND HF WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTION (HFPEF). ALTHOUGH BOTH HF PHENOTYPES CAN BE DISTINGUISHED THROUGH CLINICAL FEATURES, CO-MORBIDITY STATUS, PREDICTION SCORE, AND TREATMENT, THE CLINICAL OUTCOMES IN PATIENTS WITH HFREF AND HFPEF ARE SIMILAR. IN THIS CONTEXT, INVESTIGATION OF VARIOUS MOLECULAR AND CELLULAR MECHANISMS LEADING TO THE DEVELOPMENT AND PROGRESSION OF BOTH HF PHENOTYPES IS VERY IMPORTANT. THERE IS EMERGING EVIDENCE THAT EPIGENETIC REGULATION MAY HAVE A CLUE IN THE PATHOGENESIS OF HF. THIS REVIEW REPRESENTS CURRENT AVAILABLE EVIDENCE REGARDING THE IMPLICATION OF EPIGENETIC MODIFICATIONS IN THE DEVELOPMENT OF DIFFERENT HF PHENOTYPES AND PERSPECTIVES OF EPIGENETIC-BASED THERAPIES OF HF. 2016 2 1585 23 DNA METHYLATION PROFILING IDENTIFIES EPIGENETIC DIFFERENCES BETWEEN DIABETES PATIENTS WITH ESRD AND DIABETES PATIENTS WITHOUT NEPHROPATHY. WE IDENTIFIED POTENTIAL EPIGENETIC BIOMARKERS FOR CHRONIC KIDNEY DISEASE PROGRESSION BY COMPARING SITE-SPECIFIC DNA METHYLATION LEVELS IN MORE THAN 14,000 GENES BETWEEN AFRICAN AMERICAN AND HISPANIC DIABETES PATIENTS WITH END STAGE RENAL DISEASE (ESRD) AND DIABETES PATIENTS WITHOUT NEPHROPATHY. WE IDENTIFIED 187 GENES THAT ARE DIFFERENTIALLY METHYLATED BETWEEN THE TWO GROUPS ON AT LEAST TWO CPG SITES IN EACH GENE IN DNA EXTRACTED FROM SALIVA. OF THE 187 GENES WHOSE MEAN METHYLATION LEVELS DIFFERED BETWEEN THE TWO GROUPS, 39 GENES, OR CLOSELY RELATED GENE FAMILY MEMBERS, HAVE BEEN REPORTED TO BE INVOLVED IN KIDNEY DEVELOPMENT OR DIABETIC NEPHROPATHY, PER SE, OR HAVE BEEN ASSOCIATED WITH DIALYSIS-INDUCED CHANGES IN GENE EXPRESSION IN PERIPHERAL BLOOD CELLS. THE FACT THAT SUCH A SUBSTANTIAL FRACTION (21%) OF THE 187 CANDIDATE GENES HAVE BEEN IMPLICATED PREVIOUSLY THROUGH GENOME ASSOCIATION OR TRANSCRIPTION PROFILING STUDIES SUGGESTS STRONGLY THAT THE DNA METHYLATION DIFFERENCES WE OBSERVE ARE ASSOCIATED WITH DISEASE PREDISPOSITION AND/OR TREATMENT. THE FACT THAT THESE NEPHROPATHY AND/OR DIALYSIS-ASSOCIATED DIFFERENCES BETWEEN PATIENTS WERE IDENTIFIED IN DNA EXTRACTED FROM SALIVA OFFERS PROOF-OF-PRINCIPLE THAT INTER-INDIVIDUAL EPIGENETIC DIFFERENCES MAY PROVE USEFUL AS PREDICTIVE BIOMARKERS OF DISEASE SUSCEPTIBILITY. 2011 3 1516 27 DNA METHYLATION AS A BIOMARKER OF AGING IN EPIDEMIOLOGIC STUDIES. CANCER IS LARGELY AN AGING DISEASE. ACCELERATED BIOLOGICAL AGING MAY BE THE STRONGEST PREDICTOR OF CANCER AND OTHER CHRONIC DISEASE RISKS. IN THE ABSENCE OF RELIABLE AND QUANTIFIABLE BIOMARKERS OF AGING TO DATE, IT HAS LONG BEEN OBSERVED THAT TUMORIGENESIS SHARES DISTINCT EPIGENETIC ALTERATIONS WITH THE AGING PROCESS. RECENTLY, EPIGENETIC AGE ESTIMATES HAVE BEEN DEVELOPED BASED ON THE AVAILABILITY OF GENOME-WIDE DNA METHYLATION PROFILES, BY APPLYING IN THE PREDICTION FORMULA THE METHYLATION LEVEL AT A SUBSET OF HIGHLY PREDICTIVE METHYLATION SITES, CALLED EPIGENETIC CLOCK. THESE DNA METHYLATION AGE ESTIMATES HAVE PRODUCED REMARKABLY STRONG CORRELATIONS WITH CHRONOLOGICAL AGE, WITH A SMALL DEVIATION AND HIGH REPRODUCIBILITY ACROSS DIFFERENT AGE GROUPS AND STUDY POPULATIONS. MOREOVER, AN INCREASING NUMBER OF EPIDEMIOLOGIC STUDIES HAVE DEMONSTRATED AN INDEPENDENT ASSOCIATION OF DNA METHYLATION AGE OR THE EXTENT OF ACCELERATION WITH MORTALITY AND VARIOUS AGING-RELATED CONDITIONS, EVEN AFTER ACCOUNTING FOR DIFFERENCES IN CHRONOLOGICAL AGE AND OTHER RISK FACTORS. ALTHOUGH EPIGENETIC PROFILES ARE KNOWN TO BE TISSUE-SPECIFIC, BOTH TARGET TISSUE- AND MULTIPLE TISSUE-DERIVED ESTIMATES APPEAR TO PERFORM WELL TO CAPTURE WHAT IS THOUGHT TO BE THE CUMULATIVE EPIGENETIC DRIFT THAT REPRESENTS A MULTIFACTORIAL DEGENERATIVE PROCESS ACROSS TISSUES AND ORGANISMS. FURTHER REFINEMENT OF THE EPIGENETIC AGE ESTIMATES IS ANTICIPATED OVER TIME TO ACCOMMODATE A BETTER TECHNOLOGICAL COVERAGE OF THE METHYLOME AND A BETTER UNDERSTANDING OF THE BIOLOGY UNDERLYING PREDICTIVE REGIONS. EPIDEMIOLOGIC PRINCIPLES WILL REMAIN CRITICAL FOR THE EVALUATION OF RESEARCH FINDINGS INVOLVING, FOR EXAMPLE, DIFFERENT STUDY POPULATIONS, DESIGN, FOLLOW-UP TIME, AND QUALITY OF COVARIATE DATA. OVERALL, THE EPIGENETIC AGE ESTIMATES ARE AN EXCITING DEVELOPMENT WITH USEFUL IMPLICATIONS FOR BIOMEDICAL RESEARCH OF HEALTHY AGING AND DISEASE PREVENTION AND CONTROL. 2018 4 6027 16 THE BLOOD DNA METHYLATION CLOCK GRIMAGE IS A ROBUST SURROGATE FOR AIRWAY EPITHELIA AGING. ONE KEY FEATURE OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS THAT ITS PREVALENCE INCREASES EXPONENTIALLY WITH AGE. DNA METHYLATION CLOCKS HAVE BECOME POWERFUL BIOMARKERS TO DETECT ACCELERATED AGING IN A VARIETY OF DISEASES AND CAN HELP PROGNOSE OUTCOMES IN SEVERE COPD. THIS STUDY INVESTIGATED WHICH DNA METHYLATION CLOCK COULD BEST REFLECT AIRWAY EPIGENETIC AGE WHEN USED IN MORE ACCESSIBLE BLOOD SAMPLES. OUR ANALYSES SHOWED THAT OUT OF SIX DNA METHYLATION CLOCKS INVESTIGATED, DNAMGRIMAGE DEMONSTRATED THE STRONGEST CORRELATION AND THE SMALLEST DIFFERENCE BETWEEN THE AIRWAY EPITHELIUM AND BLOOD. OUR FINDINGS SUGGESTS THAT BLOOD DNAMGRIMAGE ACCURATELY REFLECTS AIRWAY EPIGENETIC AGE OF INDIVIDUALS AND THAT ITS ELEVATION IS HIGHLY ASSOCIATED WITH COPD. 2022 5 70 20 A METHOD TO DETECT DIFFERENTIALLY METHYLATED LOCI WITH NEXT-GENERATION SEQUENCING. EPIGENETIC CHANGES, ESPECIALLY DNA METHYLATION AT CPG LOCI HAVE IMPORTANT IMPLICATIONS IN CANCER AND OTHER COMPLEX DISEASES. WITH THE DEVELOPMENT OF NEXT-GENERATION SEQUENCING (NGS), IT IS FEASIBLE TO GENERATE DATA TO INTERROGATE THE DIFFERENCE IN METHYLATION STATUS FOR GENOME-WIDE LOCI USING CASE-CONTROL DESIGN. HOWEVER, A PROPER AND EFFICIENT STATISTICAL TEST IS LACKING. THERE ARE SEVERAL CHALLENGES. FIRST, UNLIKE METHYLATION EXPERIMENTS USING MICROARRAYS, WHERE THERE IS ONE MEASURE OF METHYLATION FOR ONE INDIVIDUAL AT A PARTICULAR CPG SITE, HERE WE HAVE THE COUNTS OF METHYLATION ALLELE AND UNMETHYLATION ALLELE FOR EACH INDIVIDUAL. SECOND, DUE TO THE NATURE OF SAMPLE PREPARATION, THE MEASURED METHYLATION REFLECTS THE METHYLATION STATUS OF A MIXTURE OF CELLS INVOLVED IN SAMPLE PREPARATION. THEREFORE, THE UNDERLYING DISTRIBUTION OF THE MEASURED METHYLATION LEVEL IS UNKNOWN, AND A ROBUST TEST IS MORE DESIRABLE THAN PARAMETRIC APPROACH. THIRD, CURRENTLY NGS MEASURES METHYLATION AT OVER 2 MILLION CPG SITES. ANY STATISTICAL TESTS HAVE TO BE COMPUTATIONALLY EFFICIENT IN ORDER TO BE APPLIED TO THE NGS DATA. TAKING THESE CHALLENGES INTO ACCOUNT, WE PROPOSE A TEST FOR DIFFERENTIAL METHYLATION BASED ON CLUSTERED DATA ANALYSIS BY MODELING THE METHYLATION COUNTS. WE PERFORMED SIMULATIONS TO SHOW THAT IT IS ROBUST UNDER SEVERAL DISTRIBUTIONS FOR THE MEASURED METHYLATION LEVELS. IT HAS GOOD POWER AND IS COMPUTATIONALLY EFFICIENT. FINALLY, WE APPLY THE TEST TO OUR NGS DATA ON CHRONIC LYMPHOCYTIC LEUKEMIA. THE RESULTS INDICATE THAT IT IS A PROMISING AND PRACTICAL TEST. 2013 6 5685 28 SHOULD WE INVEST IN BIOLOGICAL AGE PREDICTORS TO TREAT COLORECTAL CANCER IN OLDER ADULTS? COLORECTAL CANCER (CRC) IS A CHRONIC DISEASE OF THE OLD POPULATION WITH SLOW DEVELOPMENT PROGRESSING INTO CLINICAL SIGNS AND SYMPTOMS. BIOLOGICAL AGING IS CHARACTERIZED BY E.G. MITOCHONDRIAL DYSFUNCTION AND EPIGENETIC ALTERATIONS (E.G. METHYLATION) - MECHANISMS THAT ARE ALSO IMPORTANT IN CANCER DEVELOPMENT. FOR CRC, SPECIFIC TYPES OF TUMORS ARE DISTINGUISHABLE BY THEIR METHYLATION PATTERNS AND SEVERAL DETECTION METHODS USING DIFFERENT EPIGENETIC MARKS HAVE BEEN DEVELOPED AS SIGNATURES FOR THE DISEASE. BIOLOGICAL AGE ASSESSED BY DNA METHYLATION PATTERNS FROM BLOOD, I.E. THE EPIGENETIC CLOCK, IS HIGHER IN CRC PATIENTS COMPARED TO CONTROLS, AND MAY BE A TOOL FOR IDENTIFYING INDIVIDUALS AT INCREASED RISK FOR CRC. OTHER TYPES OF BIOMARKERS OF AGING ARE USEFUL TO CALCULATE BIOLOGICAL AGE, SUCH AS METABOLITES, PROTEIN LEVELS, INFLAMMATORY MARKERS AND CLINICAL BIOMARKERS, WHERE COMPOSITE SCORES OF BIOMARKERS HAVE BEEN USED TO ASSESS THE RISK OF CRC AND COLORECTAL ADENOMAS. CLINICAL ASSESSMENTS OF BIOLOGICAL AGING INCLUDES FRAILTY, WHICH IS A GERIATRIC SYNDROME CHARACTERIZED BY INCREASED VULNERABILITY TO ADVERSE OUTCOMES. MORE THAN HALF OF THE CRC PATIENTS ARE ESTIMATED TO BE FRAIL OR PRE-FRAIL, AND THESE INDIVIDUALS ARE AT INCREASED RISK OF POSTOPERATIVE COMPLICATIONS, POORER PROGNOSIS, TREATMENT INTOLERANCE AND DEATH. HENCE, CONSIDERING FRAILTY AS PART OF BIOLOGICAL AGE IN CRC PATIENTS MAY HELP IDENTIFYING THOSE AT NEED OF CLOSE MONITORING. IN SUMMARY, FUTURE SCREENING PROGRAMS FOR CRC MAY MAKE USE OF BIOLOGICAL AGE ASSESSMENTS, E.G. BY EPIGENETIC CLOCK OR COMPOSITE SCORES. MONITORING DISEASE RELAPSE AND TREATMENT RESPONSE SHOULD BE ENHANCED IN FRAIL INDIVIDUALS FOR BETTER PROGNOSIS. 2020 7 2643 19 EPIGENOMIC ASSOCIATION ANALYSIS IDENTIFIES SMOKING-RELATED DNA METHYLATION SITES IN AFRICAN AMERICANS. CIGARETTE SMOKING IS AN ENVIRONMENTAL RISK FACTOR FOR MANY CHRONIC DISEASES, AND DISEASE RISK CAN OFTEN BE MANAGED BY SMOKING CONTROL. SMOKING CAN INDUCE CELLULAR AND MOLECULAR CHANGES, INCLUDING EPIGENETIC MODIFICATION, BUT THE SHORT- AND LONG-TERM EPIGENETIC MODIFICATIONS CAUSED BY CIGARETTE SMOKING AT THE GENE LEVEL HAVE NOT BEEN WELL UNDERSTOOD. RECENT STUDIES HAVE IDENTIFIED SMOKING-RELATED DNA METHYLATION (DNAM) SITES IN CAUCASIANS. TO DETERMINE WHETHER THE SAME DNAM SITES ASSOCIATE WITH SMOKING IN AFRICAN AMERICANS, AND TO IDENTIFY NOVEL SMOKING-RELATED DNAM SITES, WE CONDUCTED A METHYLOME-WIDE ASSOCIATION STUDY OF CIGARETTE SMOKING USING A DISCOVERY SAMPLE OF 972 AFRICAN AMERICANS, AND A REPLICATION SAMPLE OF 239 AFRICAN AMERICANS WITH TWO ARRAY-BASED METHODS. AMONG 15 DNAM SITES SIGNIFICANTLY ASSOCIATED WITH SMOKING AFTER CORRECTION FOR MULTIPLE TESTING IN OUR DISCOVERY SAMPLE, 5 DNAM SITES ARE REPLICATED IN AN INDEPENDENT COHORT, AND 14 SITES IN THE REPLICATION SAMPLE HAVE EFFECTS IN THE SAME DIRECTION AS IN THE DISCOVERY SAMPLE. THE TOP TWO SMOKING-RELATED DNAM SITES IN F2RL3 (FACTOR II RECEPTOR-LIKE 3) AND GPR15 (G-PROTEIN-COUPLED RECEPTOR 15) OBSERVED IN AFRICAN AMERICANS ARE CONSISTENT WITH PREVIOUS FINDINGS IN CAUCASIANS. THE ASSOCIATIONS BETWEEN THE REPLICATED DNAM SITES AND SMOKING REMAIN SIGNIFICANT AFTER ADJUSTING FOR GENETIC BACKGROUND. DESPITE THE DISTINCT GENETIC BACKGROUND BETWEEN AFRICAN AMERICANS AND CAUCASIANS, THE DNAM FROM THE TWO ETHNIC GROUPS SHARES COMMON ASSOCIATIONS WITH CIGARETTE SMOKING, WHICH SUGGESTS A COMMON MOLECULAR MECHANISM OF EPIGENETIC MODIFICATION INFLUENCED BY ENVIRONMENTAL EXPOSURE. 2013 8 1599 20 DNA METHYLATION SIGNATURE OF CHILDHOOD CHRONIC PHYSICAL AGGRESSION IN T CELLS OF BOTH MEN AND WOMEN. BACKGROUND: HIGH FREQUENCY OF PHYSICAL AGGRESSION IS THE CENTRAL FEATURE OF SEVERE CONDUCT DISORDER AND IS ASSOCIATED WITH A WIDE RANGE OF SOCIAL, MENTAL AND PHYSICAL HEALTH PROBLEMS. WE HAVE PREVIOUSLY TESTED THE HYPOTHESIS THAT DIFFERENTIAL DNA METHYLATION SIGNATURES IN PERIPHERAL T CELLS ARE ASSOCIATED WITH A CHRONIC AGGRESSION TRAJECTORY IN MALES. DESPITE THE FACT THAT SEX DIFFERENCES APPEAR TO PLAY A PIVOTAL ROLE IN DETERMINING THE DEVELOPMENT, MAGNITUDE AND FREQUENCY OF AGGRESSION, MOST OF PREVIOUS STUDIES FOCUSED ON MALES, SO LITTLE IS KNOWN ABOUT FEMALE CHRONIC PHYSICAL AGGRESSION. WE THEREFORE TESTED HERE WHETHER OR NOT THERE IS A SIGNATURE OF PHYSICAL AGGRESSION IN FEMALE DNA METHYLATION AND, IF THERE IS, HOW IT RELATES TO THE SIGNATURE OBSERVED IN MALES. METHODOLOGY/PRINCIPAL FINDINGS: METHYLATION PROFILES WERE CREATED USING THE METHOD OF METHYLATED DNA IMMUNOPRECIPITATION (MEDIP) FOLLOWED BY MICROARRAY HYBRIDIZATION AND STATISTICAL AND BIOINFORMATIC ANALYSES ON T CELL DNA OBTAINED FROM ADULT WOMEN WHO WERE FOUND TO BE ON A CHRONIC PHYSICAL AGGRESSION TRAJECTORY (CPA) BETWEEN 6 AND 12 YEARS OF AGE COMPARED TO WOMEN WHO FOLLOWED A NORMAL PHYSICAL AGGRESSION TRAJECTORY. WE CONFIRMED THE EXISTENCE OF A WELL-DEFINED, GENOME-WIDE SIGNATURE OF DNA METHYLATION ASSOCIATED WITH CHRONIC PHYSICAL AGGRESSION IN THE PERIPHERAL T CELLS OF ADULT FEMALES THAT INCLUDES MANY OF THE GENES SIMILARLY ASSOCIATED WITH PHYSICAL AGGRESSION IN THE SAME CELL TYPES OF ADULT MALES. CONCLUSIONS: THIS STUDY IN A SMALL NUMBER OF WOMEN PRESENTS PRELIMINARY EVIDENCE FOR A GENOME-WIDE VARIATION IN PROMOTER DNA METHYLATION THAT ASSOCIATES WITH CPA IN WOMEN THAT WARRANT LARGER STUDIES FOR FURTHER VERIFICATION. A SIGNIFICANT PROPORTION OF THESE ASSOCIATIONS WERE PREVIOUSLY OBSERVED IN MEN WITH CPA SUPPORTING THE HYPOTHESIS THAT THE EPIGENETIC SIGNATURE OF EARLY LIFE AGGRESSION IN FEMALES IS COMPOSED OF A COMPONENT SPECIFIC TO FEMALES AND ANOTHER COMMON TO BOTH MALES AND FEMALES. 2014 9 50 28 A DEEP LEARNING MODEL FOR EARLY RISK PREDICTION OF HEART FAILURE WITH PRESERVED EJECTION FRACTION BY DNA METHYLATION PROFILES COMBINED WITH CLINICAL FEATURES. BACKGROUND: HEART FAILURE WITH PRESERVED EJECTION FRACTION (HFPEF), AFFECTED COLLECTIVELY BY GENETIC AND ENVIRONMENTAL FACTORS, IS THE COMMON SUBTYPE OF CHRONIC HEART FAILURE. ALTHOUGH THE AVAILABLE RISK ASSESSMENT METHODS FOR HFPEF HAVE ACHIEVED SOME PROGRESS, THEY WERE BASED ON CLINICAL OR GENETIC FEATURES ALONE. HERE, WE HAVE DEVELOPED A DEEP LEARNING FRAMEWORK, HFMERISK, USING BOTH 5 CLINICAL FEATURES AND 25 DNA METHYLATION LOCI TO PREDICT THE EARLY RISK OF HFPEF IN THE FRAMINGHAM HEART STUDY COHORT. RESULTS: THE FRAMEWORK INCORPORATES LEAST ABSOLUTE SHRINKAGE AND SELECTION OPERATOR AND EXTREME GRADIENT BOOSTING-BASED FEATURE SELECTION, AS WELL AS A FACTORIZATION-MACHINE BASED NEURAL NETWORK-BASED RECOMMENDER SYSTEM. MODEL DISCRIMINATION AND CALIBRATION WERE ASSESSED USING THE AUC AND HOSMER-LEMESHOW TEST. HFMERISK, INCLUDING 25 CPGS AND 5 CLINICAL FEATURES, HAVE ACHIEVED THE AUC OF 0.90 (95% CONFIDENCE INTERVAL 0.88-0.92) AND HOSMER-LEMESHOW STATISTIC WAS 6.17 (P = 0.632), WHICH OUTPERFORMED MODELS WITH CLINICAL CHARACTERISTICS OR DNA METHYLATION LEVELS ALONE, PUBLISHED CHRONIC HEART FAILURE RISK PREDICTION MODELS AND OTHER BENCHMARK MACHINE LEARNING MODELS. OUT OF THEM, THE DNA METHYLATION LEVELS OF TWO CPGS WERE SIGNIFICANTLY CORRELATED WITH THE PAIRED TRANSCRIPTOME LEVELS (R < -0.3, P < 0.05). BESIDES, DNA METHYLATION LOCUS IN HFMERISK WERE ASSOCIATED WITH INTERCELLULAR SIGNALING AND INTERACTION, AMINO ACID METABOLISM, TRANSPORT AND ACTIVATION AND THE CLINICAL VARIABLES WERE ALL RELATED WITH THE MECHANISM OF OCCURRENCE OF HFPEF. TOGETHER, THESE FINDINGS GIVE NEW EVIDENCE INTO THE HFMERISK MODEL. CONCLUSION: OUR STUDY PROPOSES AN EARLY RISK ASSESSMENT FRAMEWORK FOR HFPEF INTEGRATING BOTH CLINICAL AND EPIGENETIC FEATURES, PROVIDING A PROMISING PATH FOR CLINICAL DECISION MAKING. 2022 10 4707 18 NMR PLASMA METABOLOMICS STUDY OF PATIENTS OVERCOMING ACUTE MYOCARDIAL INFARCTION: IN THE FIRST 12 H AFTER ONSET OF CHEST PAIN WITH STATISTICAL DISCRIMINATION TOWARDS METABOLOMIC BIOMARKERS. ACUTE MYOCARDIAL INFARCTION (AMI) IS ONE OF THE LEADING CAUSES OF DEATH AMONG ADULTS IN OLDER AGE. UNDERSTANDING MECHANISMS HOW ORGANISM RESPONDS TO ISCHEMIA IS ESSENTIAL FOR THE ISCHEMIC PATIENT'S PREVENTION AND TREATMENT. DESPITE THE GREAT PREVALENCE AND INCIDENCE ONLY A SMALL NUMBER OF STUDIES UTILIZE A METABOLOMIC APPROACH TO DESCRIBE AMI CONDITION. RECENT STUDIES HAVE SHOWN THE IMPACT OF METABOLITES ON EPIGENETIC CHANGES, IN THESE STUDIES PLASMA METABOLITES WERE RELATED TO NEUROLOGICAL OUTCOME OF THE PATIENTS MAKING METABOLOMIC STUDIES INCREASINGLY INTERESTING. THE AIM OF THIS STUDY WAS TO DESCRIBE METABOLOMIC RESPONSE OF AN ORGANISM TO ISCHEMIC STRESS THROUGH THE CHANGES IN ENERGETIC METABOLITES AND AMINOACIDS IN BLOOD PLASMA IN PATIENTS OVERCOMING ACUTE MYOCARDIAL INFARCTION. BLOOD PLASMA FROM PATIENTS IN THE FIRST 12 H AFTER ONSET OF CHEST PAIN WAS COLLECTED AND COMPARED WITH VOLUNTEERS WITHOUT ANY HISTORY OF ISCHEMIC DISEASES VIA NMR SPECTROSCOPY. LOWERED PLASMA LEVELS OF PYRUVATE, ALANINE, GLUTAMINE AND NEUROTRANSMITTER PRECURSORS TYROSINE AND TRYPTOPHAN WERE FOUND. FURTHER, WE OBSERVED INCREASED PLASMA LEVELS OF 3-HYDROXYBUTYRATE AND ACETOACETATE IN BALANCE WITH DECREASED LEVEL OF LIPOPROTEINS FRACTION, SUGGESTING THE ONGOING KETONIC STATE OF AN ORGANISM. DISCRIMINATORY ANALYSIS SHOWED VERY PROMISING PERFORMANCE WHERE COMPOUNDS: LIPOPROTEINS, ALANINE, PYRUVATE, GLUTAMINE, TRYPTOPHAN AND 3-HYDROXYBUTYRATE WERE OF THE HIGHEST DISCRIMINATORY POWER WITH FEASIBILITY OF SUCCESSFUL STATISTICAL DISCRIMINATION. 2020 11 287 19 AGING AND CHRONIC SUN EXPOSURE CAUSE DISTINCT EPIGENETIC CHANGES IN HUMAN SKIN. EPIGENETIC CHANGES ARE WIDELY CONSIDERED TO PLAY AN IMPORTANT ROLE IN AGING, BUT EXPERIMENTAL EVIDENCE TO SUPPORT THIS HYPOTHESIS HAS BEEN SCARCE. WE HAVE USED ARRAY-BASED ANALYSIS TO DETERMINE GENOME-SCALE DNA METHYLATION PATTERNS FROM HUMAN SKIN SAMPLES AND TO INVESTIGATE THE EFFECTS OF AGING, CHRONIC SUN EXPOSURE, AND TISSUE VARIATION. OUR RESULTS REVEAL A HIGH DEGREE OF TISSUE SPECIFICITY IN THE METHYLATION PATTERNS AND ALSO SHOWED VERY LITTLE INTERINDIVIDUAL VARIATION WITHIN TISSUES. DATA STRATIFICATION BY AGE REVEALED THAT DNA FROM OLDER INDIVIDUALS WAS CHARACTERIZED BY A SPECIFIC HYPERMETHYLATION PATTERN AFFECTING LESS THAN 1% OF THE MARKERS ANALYZED. INTERESTINGLY, STRATIFICATION BY SUN EXPOSURE PRODUCED A FUNDAMENTALLY DIFFERENT PATTERN WITH A SIGNIFICANT TREND TOWARDS HYPOMETHYLATION. OUR RESULTS THUS IDENTIFY DEFINED AGE-RELATED DNA METHYLATION CHANGES AND SUGGEST THAT THESE ALTERATIONS MIGHT CONTRIBUTE TO THE PHENOTYPIC CHANGES ASSOCIATED WITH SKIN AGING. 2010 12 4025 26 LUNG CANCER AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE: NEEDS AND OPPORTUNITIES FOR INTEGRATED RESEARCH. LUNG CANCER AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) ARE LEADING CAUSES OF MORBIDITY AND MORTALITY IN THE UNITED STATES AND WORLDWIDE. THEY SHARE A COMMON ENVIRONMENTAL RISK FACTOR IN CIGARETTE SMOKE EXPOSURE AND A GENETIC PREDISPOSITION REPRESENTED BY THE INCIDENCE OF THESE DISEASES IN ONLY A FRACTION OF SMOKERS. THE PRESENCE OF COPD INCREASES THE RISK OF LUNG CANCER UP TO 4.5-FOLD. TO INVESTIGATE COMMONALITIES IN DISEASE MECHANISMS AND PERSPECTIVES FOR DISEASE CHEMOPREVENTION, THE NATIONAL HEART, LUNG, AND BLOOD INSTITUTE (NHLBI) AND THE NATIONAL CANCER INSTITUTE (NCI) HELD A WORKSHOP. THE PARTICIPANTS IDENTIFIED FOUR RESEARCH OBJECTIVES: 1) CLARIFY COMMON EPIDEMIOLOGICAL CHARACTERISTICS OF LUNG CANCER AND COPD; 2) IDENTIFY SHARED GENETIC AND EPIGENETIC RISK FACTORS; 3) IDENTIFY AND VALIDATE BIOMARKERS, MOLECULAR SIGNATURES, AND IMAGING-DERIVED MEASUREMENTS OF EACH DISEASE; AND 4) DETERMINE COMMON AND DISPARATE PATHOGENETIC MECHANISMS. THESE OBJECTIVES SHOULD BE REACHED VIA FOUR RESEARCH APPROACHES: 1) IDENTIFY, PUBLICIZE, AND ENABLE THE EVALUATION AND ANALYSIS OF EXISTING DATASETS AND REPOSITORIES OF BIOSPECIMENS; 2) OBTAIN PHENOTYPIC AND OUTCOME DATA AND BIOSPECIMENS FROM LARGE STUDIES OF SUBJECTS WITH AND/OR AT RISK FOR COPD AND LUNG CANCER; 3) DEVELOP AND USE ANIMAL AND OTHER PRECLINICAL MODELS TO INVESTIGATE PATHOGENETIC LINKS BETWEEN THE DISEASES; AND 4) CONDUCT EARLY-PHASE CLINICAL TRIALS OF POTENTIAL CHEMOPREVENTIVE AGENTS. TO FOSTER MUCH NEEDED RESEARCH INTERACTIONS, TWO FINAL RECOMMENDATIONS WERE MADE BY THE PARTICIPANTS: 1) INCORPORATE BASELINE PHENOTYPING AND OUTCOME MEASURES FOR BOTH DISEASES IN FUTURE LONGITUDINAL STUDIES OF EACH DISEASE AND 2) EXPAND COLLABORATIVE EFFORTS BETWEEN THE NCI AND NHLBI. 2009 13 1780 21 EDUCATION AND LIFESTYLE FACTORS ARE ASSOCIATED WITH DNA METHYLATION CLOCKS IN OLDER AFRICAN AMERICANS. DNA METHYLATION (DNAM) CLOCKS ARE IMPORTANT BIOMARKERS OF CELLULAR AGING AND ARE ASSOCIATED WITH A VARIETY OF AGE-RELATED CHRONIC DISEASES AND ALL-CAUSE MORTALITY. EXAMINING THE RELATIONSHIP BETWEEN EDUCATION AND LIFESTYLE RISK FACTORS FOR AGE-RELATED DISEASES AND MULTIPLE DNAM CLOCKS CAN INCREASE THE UNDERSTANDING OF HOW RISK FACTORS CONTRIBUTE TO AGING AT THE CELLULAR LEVEL. THIS STUDY EXPLORED THE ASSOCIATION BETWEEN EDUCATION OR LIFESTYLE RISK FACTORS FOR AGE-RELATED DISEASES AND THE ACCELERATION OF FOUR DNAM CLOCKS, INCLUDING INTRINSIC (IEAA) AND EXTRINSIC EPIGENETIC AGE ACCELERATION (EEAA), PHENOAGE ACCELERATION (PHENOAA), AND GRIMAGE ACCELERATION (GRIMAA) IN THE AFRICAN AMERICAN PARTICIPANTS OF THE GENETIC EPIDEMIOLOGY NETWORK OF ARTERIOPATHY. WE PERFORMED BOTH CROSS-SECTIONAL AND LONGITUDINAL ANALYSES. IN CROSS-SECTIONAL ANALYSES, GENDER, EDUCATION, BMI, SMOKING, AND ALCOHOL CONSUMPTION WERE ALL INDEPENDENTLY ASSOCIATED WITH GRIMAA, WHEREAS ONLY SOME OF THEM WERE ASSOCIATED WITH OTHER CLOCKS. THE EFFECT OF SMOKING AND EDUCATION ON GRIMAA VARIED BY GENDER. LONGITUDINAL ANALYSES SUGGEST THAT AGE AND BMI CONTINUED TO INCREASE GRIMAA, AND THAT AGE AND CURRENT SMOKING CONTINUED TO INCREASE PHENOAA AFTER CONTROLLING DNAM CLOCKS AT BASELINE. IN CONCLUSION, EDUCATION AND COMMON LIFESTYLE RISK FACTORS WERE ASSOCIATED WITH MULTIPLE DNAM CLOCKS. HOWEVER, THE ASSOCIATION WITH EACH RISK FACTOR VARIED BY CLOCK, WHICH SUGGESTS THAT DIFFERENT CLOCKS MAY CAPTURE ADVERSE EFFECTS FROM DIFFERENT ENVIRONMENTAL STIMULI. 2019 14 1068 21 CLL INTRACLONAL FRACTIONS EXHIBIT ESTABLISHED AND RECENTLY ACQUIRED PATTERNS OF DNA METHYLATION. INTRACLONAL SUBPOPULATIONS OF CIRCULATING CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) CELLS WITH DIFFERENT PROLIFERATIVE HISTORIES AND RECIPROCAL SURFACE EXPRESSION OF CXCR4 AND CD5 HAVE BEEN OBSERVED IN THE PERIPHERAL BLOOD OF CLL PATIENTS AND NAMED PROLIFERATIVE (PF), INTERMEDIATE (IF), AND RESTING (RF) CELLULAR FRACTIONS. HERE, WE FOUND THAT THESE INTRACLONAL CIRCULATING FRACTIONS SHARE PERSISTENT DNA METHYLATION SIGNATURES LARGELY ASSOCIATED WITH THE MUTATION STATUS OF THE IMMUNOGLOBULIN HEAVY CHAIN LOCUS (IGHV) AND THEIR ORIGINS FROM DISTINCT STAGES OF DIFFERENTIATION OF ANTIGEN-EXPERIENCED B CELLS. INCREASED LEUKEMIC BIRTH RATE, HOWEVER, SHOWED A VERY LIMITED IMPACT ON DNA METHYLATION OF CIRCULATING CLL FRACTIONS INDEPENDENT OF IGHV MUTATION STATUS. ADDITIONALLY, DNA METHYLATION HETEROGENEITY INCREASED AS LEUKEMIC CELLS ADVANCED FROM PF TO RF IN THE PERIPHERAL BLOOD. THIS FREQUENTLY CO-OCCURRED WITH HETEROCHROMATIN HYPOMETHYLATION AND HYPERMETHYLATION OF POLYCOMB-REPRESSED REGIONS IN THE PF, SUGGESTING ACCUMULATION OF LONGEVITY-ASSOCIATED EPIGENETIC FEATURES IN RECENTLY BORN CELLS. ON THE OTHER HAND, TRANSCRIPTIONAL DIFFERENCES BETWEEN PAIRED INTRACLONAL FRACTIONS CONFIRMED THEIR PROLIFERATIVE EXPERIENCE AND FURTHER SUPPORTED A LINEAR ADVANCEMENT FROM PF TO RF IN THE PERIPHERAL BLOOD. SEVERAL OF THESE DIFFERENTIALLY EXPRESSED GENES SHOWED UNIQUE ASSOCIATIONS WITH CLINICAL OUTCOME NOT EVIDENT IN THE BULK CLONE, SUPPORTING THE PATHOLOGICAL AND THERAPEUTIC RELEVANCE OF STUDYING INTRACLONAL CLL FRACTIONS. WE CONCLUDE THAT INDEPENDENT METHYLATION AND TRANSCRIPTIONAL LANDSCAPES REFLECT BOTH PREEXISTING CELL-OF-ORIGIN FINGERPRINTS AND MORE RECENTLY ACQUIRED HALLMARKS ASSOCIATED WITH THE LIFE CYCLE OF CIRCULATING CLL CELLS. 2020 15 3936 19 LIVING IN ENDEMIC AREA FOR INFECTIOUS DISEASES ACCELERATES EPIGENETIC AGE. INFLAMMAGING IS A LOW-GRADE INFLAMMATORY STATE GENERATED BY THE AGING PROCESS THAT CAN CONTRIBUTE TO FRAILTY AND AGE-RELATED DISEASES IN THE ELDERLY. HOWEVER, IT CAN HAVE DISTINCT EFFECTS IN THE ELDERLY LIVING IN ENDEMIC AREAS FOR INFECTIOUS DISEASES. AN INCREASED INFLAMMATORY RESPONSE MAY CONFER PROTECTION AGAINST INFECTIOUS AGENTS IN THESE AREAS, ALTHOUGH THIS ADVANTAGE CAN CAUSE ACCELERATING EPIGENETIC AGING. IN THIS STUDY, WE EVALUATED THE INFLAMMATORY PROFILE AND THE EPIGENETIC AGE OF INFECTED AND NONINFECTED INDIVIDUALS FROM AN ENDEMIC AREA IN BRAZIL. THE PROFILE OF CYTOKINES, CHEMOKINES AND GROWTH FACTORS ANALYZED IN THE SERA OF THE TWO GROUPS OF INDIVIDUALS SHOWED SIMILARITIES, ALTHOUGH INFECTED INDIVIDUALS HAD A HIGHER CONCENTRATION OF THESE MEDIATORS. A SIGNIFICANT INCREASE IN IL-1RA, CXCL8, CCL2, CCL3 AND CCL4 PRODUCTION WAS ASSOCIATED WITH LEPROSY INFECTION. NOTABLY, ELDERLY INDIVIDUALS DISPLAYED DISTINCT IMMUNE RESPONSES ASSOCIATED WITH THEIR INFECTION STATUS WHEN COMPARED TO ADULTS SUGGESTING AN ADAPTIVE REMODELLING OF THEIR IMMUNE RESPONSES. EPIGENETIC ANALYSIS ALSO SHOWED THAT THERE WAS NO DIFFERENCE IN EPIGENETIC AGE BETWEEN THE TWO GROUPS OF INDIVIDUALS. HOWEVER, INDIVIDUALS FROM THE ENDEMIC AREA HAD A SIGNIFICANT ACCELERATED AGING WHEN COMPARED TO INDIVIDUALS FROM SAO PAULO, A NON-ENDEMIC AREA IN BRAZIL. MOREOVER, THE LATTER COHORT WAS ALSO EPIGENETICALLY AGED IN RELATION TO AN ITALIAN COHORT. OUR DATA SHOWS THAT LIVING IN ENDEMIC AREAS FOR CHRONIC INFECTIOUS DISEASES RESULTS IN REMODELLING OF INFLAMMAGING AND ACCELERATION OF EPIGENETIC AGING IN INDIVIDUALS REGARDLESS OF THEIR INFECTIOUS STATUS. IT ALSO HIGHLIGHTS THAT GEOGRAPHICAL, GENETIC AND ENVIRONMENTAL FACTORS INFLUENCE AGING AND IMMUNOSENESCENCE IN THEIR PACE AND PROFILE. 2022 16 2148 17 EPIGENETIC MARKERS OF RENAL FUNCTION IN AFRICAN AMERICANS. CHRONIC KIDNEY DISEASE (CKD) IS AN INCREASING CONCERN IN THE UNITED STATES DUE TO ITS RAPIDLY RISING PREVALENCE, PARTICULARLY AMONG AFRICAN AMERICANS. EPIGENETIC DNA METHYLATION MARKERS ARE BECOMING IMPORTANT BIOMARKERS OF CHRONIC DISEASES SUCH AS CKD. TO BETTER UNDERSTAND HOW THESE METHYLATION MARKERS PLAY A ROLE IN KIDNEY FUNCTION, WE MEASURED 26,428 DNA METHYLATION SITES IN 972 AFRICAN AMERICANS FROM THE GENETIC EPIDEMIOLOGY NETWORK OF ARTERIOPATHY (GENOA) STUDY. WE THEN EVALUATED (1) WHETHER EPIGENETIC MARKERS ARE ASSOCIATED WITH ESTIMATED GLOMERULAR FILTRATION RATE (EGFR), (2) WHETHER THE SIGNIFICANTLY ASSOCIATED MARKERS ARE ALSO ASSOCIATED WITH TRADITIONAL RISK FACTORS AND/OR NOVEL BIOMARKERS FOR EGFR, AND (3) HOW MUCH ADDITIONAL VARIATION IN EGFR IS EXPLAINED BY EPIGENETIC MARKERS BEYOND ESTABLISHED RISK FACTORS AND BIOMARKERS. THE MAJORITY OF METHYLATION MARKERS MOST SIGNIFICANTLY ASSOCIATED WITH EGFR (24 OUT OF THE TOP 30) APPEARED TO FUNCTION, AT LEAST IN PART, THROUGH PATHWAYS RELATED TO AGING, INFLAMMATION, OR CHOLESTEROL. HOWEVER, SIX EPIGENETIC MARKERS WERE STILL ABLE TO SIGNIFICANTLY PREDICT EGFR AFTER ADJUSTMENT FOR OTHER RISK FACTORS. THIS WORK SHOWS THAT EPIGENETIC MARKERS MAY OFFER VALUABLE NEW INSIGHT INTO THE COMPLEX PATHOPHYSIOLOGY OF CKD IN AFRICAN AMERICANS. 2013 17 1583 21 DNA METHYLATION PROFILES OF BLOOD CELLS ARE DISTINCT BETWEEN EARLY-ONSET OBESE AND CONTROL INDIVIDUALS. OBESITY IS A HIGHLY PREVALENT, CHRONIC DISORDER THAT HAS BEEN INCREASING IN INCIDENCE IN YOUNG PATIENTS. BOTH EPIGENETIC AND GENETIC ABERRATIONS MAY PLAY A ROLE IN THE PATHOGENESIS OF OBESITY. THEREFORE, IN-DEPTH EPIGENOMIC AND GENOMIC ANALYSES WILL ADVANCE OUR UNDERSTANDING OF THE DETAILED MOLECULAR MECHANISMS UNDERLYING OBESITY AND AID IN THE SELECTION OF POTENTIAL BIOMARKERS FOR OBESITY IN YOUTH. HERE, WE PERFORMED MICROARRAY-BASED DNA METHYLATION AND GENE EXPRESSION PROFILING OF PERIPHERAL WHITE BLOOD CELLS OBTAINED FROM SIX YOUNG, OBESE INDIVIDUALS AND SIX HEALTHY CONTROLS. WE OBSERVED THAT THE HIERARCHICAL CLUSTERING OF DNA METHYLATION, BUT NOT GENE EXPRESSION, CLEARLY SEGREGATES THE OBESE INDIVIDUALS FROM THE CONTROLS, SUGGESTING THAT THE METABOLIC DISTURBANCE THAT OCCURS AS A RESULT OF OBESITY AT A YOUNG AGE MAY AFFECT THE DNA METHYLATION OF PERIPHERAL BLOOD CELLS WITHOUT ACCOMPANYING TRANSCRIPTIONAL CHANGES. TO EXAMINE THE GENOME-WIDE DIFFERENCES IN THE DNA METHYLATION PROFILES OF YOUNG OBESE AND CONTROL INDIVIDUALS, WE IDENTIFIED DIFFERENTIALLY METHYLATED CPG SITES AND INVESTIGATED THEIR GENOMIC AND EPIGENOMIC CONTEXTS. THE ABERRANT DNA METHYLATION PATTERNS IN OBESE INDIVIDUALS CAN BE SUMMARIZED AS RELATIVE GAINS AND LOSSES OF DNA METHYLATION IN GENE PROMOTERS AND GENE BODIES, RESPECTIVELY. WE ALSO OBSERVED THAT THE CPG ISLANDS OF OBESE INDIVIDUALS ARE MORE SUSCEPTIBLE TO DNA METHYLATION COMPARED TO CONTROLS. OUR PILOT STUDY SUGGESTS THAT THE GENOME-WIDE ABERRANT DNA METHYLATION PATTERNS OF OBESE INDIVIDUALS MAY ADVANCE NOT ONLY OUR UNDERSTANDING OF THE EPIGENOMIC PATHOGENESIS BUT ALSO EARLY SCREENING OF OBESITY IN YOUTH. 2017 18 2411 14 EPIGENETIC SCORES FOR THE CIRCULATING PROTEOME AS TOOLS FOR DISEASE PREDICTION. PROTEIN BIOMARKERS HAVE BEEN IDENTIFIED ACROSS MANY AGE-RELATED MORBIDITIES. HOWEVER, CHARACTERISING EPIGENETIC INFLUENCES COULD FURTHER INFORM DISEASE PREDICTIONS. HERE, WE LEVERAGE EPIGENOME-WIDE DATA TO STUDY LINKS BETWEEN THE DNA METHYLATION (DNAM) SIGNATURES OF THE CIRCULATING PROTEOME AND INCIDENT DISEASES. USING DATA FROM FOUR COHORTS, WE TRAINED AND TESTED EPIGENETIC SCORES (EPISCORES) FOR 953 PLASMA PROTEINS, IDENTIFYING 109 SCORES THAT EXPLAINED BETWEEN 1% AND 58% OF THE VARIANCE IN PROTEIN LEVELS AFTER ADJUSTING FOR KNOWN PROTEIN QUANTITATIVE TRAIT LOCI (PQTL) GENETIC EFFECTS. BY PROJECTING THESE EPISCORES INTO AN INDEPENDENT SAMPLE (GENERATION SCOTLAND; N = 9537) AND RELATING THEM TO INCIDENT MORBIDITIES OVER A FOLLOW-UP OF 14 YEARS, WE UNCOVERED 137 EPISCORE-DISEASE ASSOCIATIONS. THESE ASSOCIATIONS WERE LARGELY INDEPENDENT OF IMMUNE CELL PROPORTIONS, COMMON LIFESTYLE AND HEALTH FACTORS, AND BIOLOGICAL AGING. NOTABLY, WE FOUND THAT OUR DIABETES-ASSOCIATED EPISCORES HIGHLIGHTED PREVIOUS TOP BIOMARKER ASSOCIATIONS FROM PROTEOME-WIDE ASSESSMENTS OF DIABETES. THESE EPISCORES FOR PROTEIN LEVELS CAN THEREFORE BE A VALUABLE RESOURCE FOR DISEASE PREDICTION AND RISK STRATIFICATION. 2022 19 938 21 CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) RISK IS MEDIATED BY MULTIPLE ENHANCER VARIANTS WITHIN CLL RISK LOCI. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS THE MOST COMMON ADULT LEUKEMIA IN WESTERN COUNTRIES. IT HAS A STRONG GENETIC BASIS, SHOWING A ~ 8-FOLD INCREASED RISK OF CLL IN FIRST-DEGREE RELATIVES. GENOME-WIDE ASSOCIATION STUDIES (GWAS) HAVE IDENTIFIED 41 RISK VARIANTS ACROSS 41 LOCI. HOWEVER, FOR A MAJORITY OF THE LOCI, THE FUNCTIONAL VARIANTS AND THE MECHANISMS UNDERLYING THEIR CAUSAL ROLES REMAIN UNDEFINED. HERE, WE EXAMINED THE GENETIC AND EPIGENETIC FEATURES ASSOCIATED WITH 12 INDEX VARIANTS, ALONG WITH ANY CORRELATED (R2 >/= 0.5) VARIANTS, AT THE CLL RISK LOCI LOCATED OUTSIDE OF GENE PROMOTERS. BASED ON PUBLICLY AVAILABLE CHIP-SEQ AND CHROMATIN ACCESSIBILITY DATA AS WELL AS OUR OWN CHIP-SEQ DATA FROM CLL PATIENTS, WE IDENTIFIED SIX CANDIDATE FUNCTIONAL VARIANTS AT SIX LOCI AND AT LEAST TWO CANDIDATE FUNCTIONAL VARIANTS AT EACH OF THE REMAINING SIX LOCI. THE FUNCTIONAL VARIANTS ARE PREDOMINANTLY LOCATED WITHIN ENHANCERS OR SUPER-ENHANCERS, INCLUDING BI-DIRECTIONALLY TRANSCRIBED ENHANCERS, WHICH ARE OFTEN RESTRICTED TO IMMUNE CELL TYPES. FURTHERMORE, WE FOUND THAT, AT 78% OF THE FUNCTIONAL VARIANTS, THE ALTERNATIVE ALLELES ALTERED THE TRANSCRIPTION FACTOR BINDING MOTIFS OR HISTONE MODIFICATIONS, INDICATING THE INVOLVEMENT OF THESE VARIANTS IN THE CHANGE OF LOCAL CHROMATIN STATE. FINALLY, THE ENHANCERS CARRYING FUNCTIONAL VARIANTS PHYSICALLY INTERACTED WITH GENES ENRICHED IN THE TYPE I INTERFERON SIGNALING PATHWAY, APOPTOSIS, OR TP53 NETWORK THAT ARE KNOWN TO PLAY KEY ROLES IN CLL. THESE RESULTS SUPPORT THE REGULATORY ROLES FOR INHERITED NONCODING VARIANTS IN THE PATHOGENESIS OF CLL. 2020 20 2920 22 GENE-SET ANALYSIS IS SEVERELY BIASED WHEN APPLIED TO GENOME-WIDE METHYLATION DATA. MOTIVATION: DNA METHYLATION IS AN EPIGENETIC MARK THAT CAN STABLY REPRESS GENE EXPRESSION. BECAUSE OF ITS BIOLOGICAL AND CLINICAL SIGNIFICANCE, SEVERAL METHODS HAVE BEEN DEVELOPED TO COMPARE GENOME-WIDE PATTERNS OF METHYLATION BETWEEN GROUPS OF SAMPLES. THE APPLICATION OF GENE SET ANALYSIS TO IDENTIFY RELEVANT GROUPS OF GENES THAT ARE ENRICHED FOR DIFFERENTIALLY METHYLATED GENES IS OFTEN A MAJOR COMPONENT OF THE ANALYSIS OF THESE DATA. THIS CAN BE USED, FOR EXAMPLE, TO IDENTIFY PROCESSES OR PATHWAYS THAT ARE PERTURBED IN DISEASE DEVELOPMENT. WE SHOW THAT GENE-SET ANALYSIS, AS IT IS TYPICALLY APPLIED TO GENOME-WIDE METHYLATION ASSAYS, IS SEVERELY BIASED AS A RESULT OF DIFFERENCES IN THE NUMBERS OF CPG SITES ASSOCIATED WITH DIFFERENT CLASSES OF GENES AND GENE PROMOTERS. RESULTS: WE DEMONSTRATE THIS BIAS USING PUBLISHED DATA FROM A STUDY OF DIFFERENTIAL CPG ISLAND METHYLATION IN LUNG CANCER AND A DATASET WE GENERATED TO STUDY METHYLATION CHANGES IN PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS. WE SHOW THAT SEVERAL OF THE GENE SETS THAT SEEM ENRICHED WOULD ALSO BE IDENTIFIED WITH RANDOMIZED DATA. WE SUGGEST TWO EXISTING APPROACHES THAT CAN BE ADAPTED TO CORRECT THE BIAS. ACCOUNTING FOR THE BIAS IN THE LUNG CANCER AND ULCERATIVE COLITIS DATASETS PROVIDES NOVEL BIOLOGICAL INSIGHTS INTO THE ROLE OF METHYLATION IN CANCER DEVELOPMENT AND CHRONIC INFLAMMATION, RESPECTIVELY. OUR RESULTS HAVE SIGNIFICANT IMPLICATIONS FOR MANY PREVIOUS GENOME-WIDE METHYLATION STUDIES THAT HAVE DRAWN CONCLUSIONS ON THE BASIS OF SUCH STRONGLY BIASED ANALYSIS. CONTACT: CATHAL.SEOIGHE@NUIGALWAY.IE SUPPLEMENTARY INFORMATION: SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE. 2013