1 778 116 CELL-FREE DNA METHYLATION: THE NEW FRONTIERS OF PANCREATIC CANCER BIOMARKERS' DISCOVERY. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS AMONG THE MOST LETHAL CANCER TYPES WORLD-WIDE. ITS HIGH MORTALITY IS RELATED TO THE DIFFICULTY IN THE DIAGNOSIS, WHICH OFTEN OCCURS WHEN THE DISEASE IS ALREADY ADVANCED. AS OF TODAY, NO EARLY DIAGNOSTIC TESTS ARE AVAILABLE, WHILE ONLY A LIMITED NUMBER OF PROGNOSTIC TESTS HAVE REACHED CLINICAL PRACTICE. THE MAIN REASON IS THE LACK OF RELIABLE BIOMARKERS THAT ARE ABLE TO CAPTURE THE EARLY DEVELOPMENT OR THE PROGRESSION OF THE DISEASE. HENCE, THE DISCOVERY OF BIOMARKERS FOR EARLY DIAGNOSIS OR PROGNOSIS OF PDAC REMAINS, DE FACTO, AN UNMET NEED. AN INCREASING NUMBER OF STUDIES HAS SHOWN THAT CELL-FREE DNA (CFDNA) METHYLATION ANALYSIS REPRESENTS A PROMISING NON-INVASIVE APPROACH FOR THE DISCOVERY OF BIOMARKERS WITH DIAGNOSTIC OR PROGNOSTIC POTENTIAL. IN PARTICULAR, CFDNA METHYLATION COULD BE UTILIZED FOR THE IDENTIFICATION OF DISEASE-SPECIFIC SIGNATURES IN PRE-NEOPLASTIC LESIONS OR CHRONIC PANCREATITIS (CP), REPRESENTING A SENSITIVE AND NON-INVASIVE METHOD OF EARLY DIAGNOSIS OF PDAC. IN THIS REVIEW, WE WILL DISCUSS THE ADVANTAGES AND PITFALLS OF CFDNA METHYLATION STUDIES. FURTHER, WE WILL PRESENT THE CURRENT ADVANCES IN THE DISCOVERY OF PANCREATIC CANCER BIOMARKERS WITH EARLY DIAGNOSTIC OR PROGNOSTIC POTENTIAL, FOCUSING ON PANCREAS-SPECIFIC (E.G., CUX2 OR REG1A) OR ABNORMAL (E.G., ADAMTS1 OR BNC1) CFDNA METHYLATION SIGNATURES IN HIGH RISK PRE-NEOPLASTIC CONDITIONS AND PDAC. 2019 2 3925 35 LIQUID BIOPSIES BASED ON DNA METHYLATION AS BIOMARKERS FOR THE DETECTION AND PROGNOSIS OF LUNG CANCER. LUNG CANCER (LC) IS THE MAIN CAUSE OF CANCER-RELATED MORTALITY. MOST LC PATIENTS ARE DIAGNOSED IN AN ADVANCED STAGE WHEN THE SYMPTOMS ARE OBVIOUS, AND THE PROGNOSIS IS QUITE POOR. ALTHOUGH LOW-DOSE COMPUTED TOMOGRAPHY (LDCT) IS A ROUTINE CLINICAL EXAMINATION FOR EARLY DETECTION OF LC, THE FALSE-POSITIVE RATE IS OVER 90%. AS ONE OF THE INTENSELY STUDIED EPIGENETIC MODIFICATIONS, DNA METHYLATION PLAYS A KEY ROLE IN VARIOUS DISEASES, INCLUDING CANCER AND OTHER DISEASES. HYPERMETHYLATION IN TUMOR SUPPRESSOR GENES OR HYPOMETHYLATION IN ONCOGENES IS AN IMPORTANT EVENT IN TUMORIGENESIS. REMARKABLY, DNA METHYLATION USUALLY OCCURS IN THE VERY EARLY STAGE OF MALIGNANT TUMORS. THUS, DNA METHYLATION ANALYSIS MAY PROVIDE SOME USEFUL INFORMATION ABOUT THE EARLY DETECTION OF LC. IN RECENT YEARS, LIQUID BIOPSY HAS DEVELOPED RAPIDLY. LIQUID BIOPSY CAN DETECT AND MONITOR BOTH PRIMARY AND METASTATIC MALIGNANT TUMORS AND CAN REFLECT TUMOR HETEROGENEITY. MOREOVER, IT IS A MINIMALLY INVASIVE PROCEDURE, AND IT CAUSES LESS PAIN FOR PATIENTS. THIS REVIEW SUMMARIZED VARIOUS LIQUID BIOPSIES BASED ON DNA METHYLATION FOR LC. AT FIRST, WE BRIEFLY DISCUSSED SOME EMERGING TECHNOLOGIES FOR DNA METHYLATION ANALYSIS. SUBSEQUENTLY, WE OUTLINED CELL-FREE DNA (CFDNA), SPUTUM, BRONCHOALVEOLAR LAVAGE FLUID, BRONCHIAL ASPIRATES, AND BRONCHIAL WASHINGS DNA METHYLATION-BASED LIQUID BIOPSY FOR THE EARLY DETECTION OF LC. FINALLY, THE PROGNOSTIC VALUE OF DNA METHYLATION IN CFDNA AND SPUTUM AND THE DIAGNOSTIC VALUE OF OTHER DNA METHYLATION-BASED LIQUID BIOPSIES FOR LC WERE ALSO ANALYZED. 2022 3 777 28 CELL-FREE CIRCULATING EPIGENOMIC SIGNATURES: NON-INVASIVE BIOMARKER FOR CARDIOVASCULAR AND OTHER AGE-RELATED CHRONIC DISEASES. THE BURDEN OF CARDIO-VASCULAR AND OTHER AGE-RELATED NON-COMMUNICABLE DISEASES ARE RAPIDLY INCREASING WORLDWIDE. MAJORITY OF THESE CHRONIC AILMENTS ARE CURABLE, IF DIAGNOSED AT EARLY STAGES. CANDIDATE BIOMARKERS OF EARLY DETECTION ARE THEREFORE ESSENTIAL FOR IDENTIFICATION OF HIGH-RISK INDIVIDUALS, PROMPT AND ACCURATE DISEASE DIAGNOSIS, AND TO MONITOR THERAPEUTIC RESPONSE. THE FUNCTIONAL SIGNIFICANCE OF CIRCULATING NUCLEIC ACIDS THAT RECAPITULATE SPECIFIC DISEASE PROFILES IS NOW WELL ESTABLISHED. BUT SUBTLE CHANGES IN DNA SEQUENCE MAY NOT SOLELY REFLECT THE DIFFERENTIATION OF GENE EXPRESSION PATTERNS OBSERVED IN DIVERSE SET OF DISEASES AS EPIGENETIC PHENOMENA PLAY A LARGER ROLE IN AETIOLOGY AND PATHO-PHYSIOLOGY. UNLIKE GENETIC MARKERS, KNOWLEDGE ABOUT THE DIAGNOSTIC UTILITY OF CIRCULATING EPIGENETIC SIGNATURES: METHYLATED DNA; MICRO RNA AND MODIFIED HISTONES ARE DEFICIENT. CHARACTERIZATION OF THESE NOVEL ENTITIES THROUGH OMICS-BASED MOLECULAR TECHNOLOGIES MIGHT PROMPT DEVELOPMENT OF A RANGE OF LABORATORY-BASED STRATEGIES, THEREBY ACCELERATING THEIR BROADER TRANSLATIONAL PURPOSE FOR EARLY DISEASE DIAGNOSIS, MONITORING THERAPEUTIC RESPONSE AND DRUG RESISTANCE. HOWEVER, LARGEST OPPORTUNITY FOR INNOVATION LIES IN DEVELOPING POINT-OF-CARE TESTS WITH ACCURATE DIAGNOSTIC AND HIGHER PROGNOSTIC SCORE THAT IS APPLICABLE FOR SCREENING OF HIGH-RISK POPULATIONS. 2017 4 5175 29 PREDICTORS OF BIOLOGICAL AGE: THE IMPLICATIONS FOR WELLNESS AND AGING RESEARCH. AS HEALTHSPAN AND LIFESPAN RESEARCH BREAKTHROUGHS HAVE BECOME MORE COMMONPLACE, THE NEED FOR VALID, PRACTICAL MARKERS OF BIOLOGICAL AGE IS BECOMING INCREASINGLY PARAMOUNT. THE ACCESSIBILITY AND AFFORDABILITY OF BIOLOGICAL AGE PREDICTORS THAT CAN REVEAL INFORMATION ABOUT MORTALITY AND MORBIDITY RISK, AS WELL AS REMAINING YEARS OF LIFE, HAS PROFOUND CLINICAL AND RESEARCH IMPLICATIONS. IN THIS REVIEW, WE EXAMINE 5 GROUPS OF AGING BIOMARKERS CAPABLE OF PROVIDING ACCURATE BIOLOGICAL AGE ESTIMATIONS. THE UNIQUE CAPABILITIES OF THESE BIOMARKERS HAVE FAR REACHING IMPLICATIONS FOR THE TESTING OF BOTH PHARMACEUTICAL AND NON-PHARMACEUTICAL INTERVENTIONS DESIGNED TO SLOW OR REVERSE BIOLOGICAL AGING. ADDITIONALLY, THE ENHANCED VALIDITY AND AVAILABILITY OF THESE TOOLS MAY HAVE INCREASINGLY RELEVANT CLINICAL VALUE. THE AUTHORS OF THIS REVIEW EXPLORE THOSE IMPLICATIONS, WITH AN EMPHASIS ON LIFESTYLE MODIFICATION RESEARCH, AND PROVIDE AN OVERVIEW OF THE CURRENT EVIDENCE REGARDING 5 BIOLOGICAL AGE PREDICTOR CATEGORIES: TELOMERE LENGTH, COMPOSITE BIOMARKERS, DNA METHYLATION "EPIGENETIC CLOCKS," TRANSCRIPTIONAL PREDICTORS OF BIOLOGICAL AGE, AND FUNCTIONAL AGE PREDICTORS. 2021 5 2411 23 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 6 4869 30 OSTEOARTHRITIS YEAR IN REVIEW: GENETICS, GENOMICS, EPIGENETICS. OBJECTIVE: IN THIS REVIEW, WE HAVE HIGHLIGHTED ADVANCES IN GENETICS, GENOMICS AND EPIGENETICS IN THE FIELD OF OSTEOARTHRITIS (OA) OVER THE PAST YEAR. METHODS: A LITERATURE SEARCH WAS PERFORMED USING PUBMED AND THE CRITERIA: "OSTEOARTHRITIS" AND ONE OF THE FOLLOWING TERMS "GENETIC(S), GENOMIC(S), EPIGENETIC(S), EPIGENOMIC(S), NONCODING RNA, MICRORNA, LONG NONCODING RNA, LNCRNA, CIRCULAR RNA, RNA SEQUENCING, SINGLE CELL SEQUENCING, OR DNA METHYLATION BETWEEN APRIL 1, 2019 AND APRIL 30, 2020. RESULTS: WE IDENTIFIED 653 UNIQUE PUBLICATIONS, MANY STUDIES SPANNED MULTIPLE SEARCH TERMS. WE SUMMARIZED ADVANCES RELATING TO EVOLUTIONARY GENETICS, PAIN, ETHNICITY SPECIFIC RISK FACTORS, FUNCTIONAL STUDIES OF GENE VARIANTS, AND INTERACTIONS BETWEEN CODING AND NON-CODING RNAS IN OA PATHOGENESIS. CONCLUSIONS: STUDIES HAVE IDENTIFIED VARIANTS CONTRIBUTING TO OA SUSCEPTIBILITY, CANDIDATE BIOMARKERS FOR DIAGNOSIS AND PROGNOSIS, AS WELL AS PROMISING THERAPEUTIC CANDIDATES. VALIDATION IN MULTIPLE COHORTS, MULTI-OMICS STRATEGIES, AND MACHINE LEARNING AIDED COMPUTATIONAL ANALYSES HAVE ALL CONTRIBUTED TO THE STRENGTH OF PUBLISHED LITERATURE. OPEN ACCESS DATA-SETS, GREATER SAMPLE SIZES TO CAPTURE BROADER POPULATIONS AND UNDERSTANDING DISEASE MECHANISMS BY INVESTIGATING THE INTERACTIONS BETWEEN MULTIPLE TISSUE TYPES WILL FURTHER AID IN PROGRESS TOWARDS UNDERSTANDING AND CURING OA. 2021 7 5685 34 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 8 1516 38 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 9 6112 34 THE EPIGENETIC CLOCK AS A PREDICTOR OF DISEASE AND MORTALITY RISK: A SYSTEMATIC REVIEW AND META-ANALYSIS. BACKGROUND: AGEING IS ONE OF THE PRINCIPAL RISK FACTORS FOR MANY CHRONIC DISEASES. HOWEVER, THERE IS CONSIDERABLE BETWEEN-PERSON VARIATION IN THE RATE OF AGEING AND INDIVIDUAL DIFFERENCES IN THEIR SUSCEPTIBILITY TO DISEASE AND DEATH. EPIGENETIC MECHANISMS MAY PLAY A ROLE IN HUMAN AGEING, AND DNA METHYLATION AGE BIOMARKERS MAY BE GOOD PREDICTORS OF AGE-RELATED DISEASES AND MORTALITY RISK. THE AIMS OF THIS SYSTEMATIC REVIEW WERE TO IDENTIFY AND SYNTHESISE THE EVIDENCE FOR AN ASSOCIATION BETWEEN PERIPHERALLY MEASURED DNA METHYLATION AGE AND LONGEVITY, AGE-RELATED DISEASE, AND MORTALITY RISK. METHODS: A SYSTEMATIC SEARCH WAS CONDUCTED IN LINE WITH THE PREFERRED REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSES (PRISMA) GUIDELINES. USING RELEVANT SEARCH TERMS, MEDLINE, EMBASE, COCHRANE CENTRAL REGISTER OF CONTROLLED TRIALS, AND PSYCHINFO DATABASES WERE SEARCHED TO IDENTIFY ARTICLES MEETING THE INCLUSION CRITERIA. STUDIES WERE ASSESSED FOR BIAS USING JOANNA BRIGGS INSTITUTE CRITICAL APPRAISAL CHECKLISTS. DATA WAS EXTRACTED FROM STUDIES MEASURING AGE ACCELERATION AS A PREDICTOR OF AGE-RELATED DISEASES, MORTALITY OR LONGEVITY, AND THE FINDINGS FOR SIMILAR OUTCOMES COMPARED. USING REVIEW MANAGER 5.3 SOFTWARE, TWO META-ANALYSES (ONE PER EPIGENETIC CLOCK) WERE CONDUCTED ON STUDIES MEASURING ALL-CAUSE MORTALITY. RESULTS: TWENTY-THREE RELEVANT ARTICLES WERE IDENTIFIED, INCLUDING A TOTAL OF 41,607 PARTICIPANTS. FOUR STUDIES FOCUSED ON AGEING AND LONGEVITY, 11 ON AGE-RELATED DISEASE (CANCER, CARDIOVASCULAR DISEASE, AND DEMENTIA), AND 11 ON MORTALITY. THERE WAS SOME, ALTHOUGH INCONSISTENT, EVIDENCE FOR AN ASSOCIATION BETWEEN INCREASED DNA METHYLATION AGE AND RISK OF DISEASE. META-ANALYSES INDICATED THAT EACH 5-YEAR INCREASE IN DNA METHYLATION AGE WAS ASSOCIATED AN 8 TO 15% INCREASED RISK OF MORTALITY. CONCLUSION: DUE TO THE SMALL NUMBER OF STUDIES AND HETEROGENEITY IN STUDY DESIGN AND OUTCOMES, THE ASSOCIATION BETWEEN DNA METHYLATION AGE AND AGE-RELATED DISEASE AND LONGEVITY IS INCONCLUSIVE. INCREASED EPIGENETIC AGE WAS ASSOCIATED WITH MORTALITY RISK, BUT POSITIVE PUBLICATION BIAS NEEDS TO BE CONSIDERED. FURTHER RESEARCH IS NEEDED TO DETERMINE THE EXTENT TO WHICH DNA METHYLATION AGE CAN BE USED AS A CLINICAL BIOMARKER. 2019 10 3095 37 GENOMIC APPROACHES IN THE SEARCH FOR MOLECULAR BIOMARKERS IN CHRONIC KIDNEY DISEASE. BACKGROUND: CHRONIC KIDNEY DISEASE (CKD) IS RECOGNISED AS A GLOBAL PUBLIC HEALTH PROBLEM, MORE PREVALENT IN OLDER PERSONS AND ASSOCIATED WITH MULTIPLE CO-MORBIDITIES. DIABETES MELLITUS AND HYPERTENSION ARE COMMON AETIOLOGIES FOR CKD, BUT IGA GLOMERULONEPHRITIS, MEMBRANOUS GLOMERULONEPHRITIS, LUPUS NEPHRITIS AND AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE ARE ALSO COMMON CAUSES OF CKD. MAIN BODY: CONVENTIONAL BIOMARKERS FOR CKD INVOLVING THE USE OF ESTIMATED GLOMERULAR FILTRATION RATE (EGFR) DERIVED FROM FOUR VARIABLES (SERUM CREATININE, AGE, GENDER AND ETHNICITY) ARE RECOMMENDED BY CLINICAL GUIDELINES FOR THE EVALUATION, CLASSIFICATION, AND STRATIFICATION OF CKD. HOWEVER, THESE CLINICAL BIOMARKERS PRESENT SOME LIMITATIONS, ESPECIALLY FOR EARLY STAGES OF CKD, ELDERLY INDIVIDUALS, EXTREME BODY MASS INDEX VALUES (SERUM CREATININE), OR ARE INFLUENCED BY INFLAMMATION, STEROID TREATMENT AND THYROID DYSFUNCTION (SERUM CYSTATIN C). THERE IS THEREFORE A NEED TO IDENTIFY ADDITIONAL NON-INVASIVE BIOMARKERS THAT ARE USEFUL IN CLINICAL PRACTICE TO HELP IMPROVE CKD DIAGNOSIS, INFORM PROGNOSIS AND GUIDE THERAPEUTIC MANAGEMENT. CONCLUSION: CKD IS A MULTIFACTORIAL DISEASE WITH ASSOCIATED GENETIC AND ENVIRONMENTAL RISK FACTORS. HENCE, MANY STUDIES HAVE EMPLOYED GENETIC, EPIGENETIC AND TRANSCRIPTOMIC APPROACHES TO IDENTIFY BIOMARKERS FOR KIDNEY DISEASE. IN THIS REVIEW, WE HAVE SUMMARISED THE MOST IMPORTANT STUDIES IN HUMANS INVESTIGATING GENOMIC BIOMARKERS FOR CKD IN THE LAST DECADE. SEVERAL GENES, INCLUDING UMOD, SHROOM3 AND ELMO1 HAVE BEEN STRONGLY ASSOCIATED WITH RENAL DISEASES, AND SOME OF THEIR TRAITS, SUCH AS EGFR AND SERUM CREATININE. THE ROLE OF EPIGENETIC AND TRANSCRIPTOMIC BIOMARKERS IN CKD AND RELATED DISEASES IS STILL UNCLEAR. THE COMBINATION OF MULTIPLE BIOMARKERS INTO CLASSIFIERS, INCLUDING GENOMIC, AND/OR EPIGENOMIC, MAY GIVE A MORE COMPLETE PICTURE OF KIDNEY DISEASES. 2018 11 4832 29 OMICS BIOMARKERS IN OBESITY: NOVEL ETIOLOGICAL INSIGHTS AND TARGETS FOR PRECISION PREVENTION. PURPOSE OF REVIEW: OMICS-BASED TECHNOLOGIES WERE SUGGESTED TO PROVIDE AN ADVANCED UNDERSTANDING OF OBESITY ETIOLOGY AND ITS METABOLIC CONSEQUENCES. THIS REVIEW HIGHLIGHTS THE RECENT DEVELOPMENTS IN "OMICS"-BASED RESEARCH AIMED TO IDENTIFY OBESITY-RELATED BIOMARKERS. RECENT FINDINGS: RECENT ADVANCES IN OBESITY AND METABOLISM RESEARCH INCREASINGLY RELY ON NEW TECHNOLOGIES TO IDENTIFY MECHANISMS IN THE DEVELOPMENT OF OBESITY USING VARIOUS "OMICS" PLATFORMS. GENETIC AND EPIGENETIC BIOMARKERS THAT TRANSLATE INTO CHANGES IN TRANSCRIPTOME, PROTEOME, AND METABOLOME COULD SERVE AS TARGETS FOR OBESITY PREVENTION. DESPITE A NUMBER OF PROMISING CANDIDATE BIOMARKERS, THERE IS AN INCREASED DEMAND FOR LARGER PROSPECTIVE COHORT STUDIES TO VALIDATE FINDINGS AND DETERMINE BIOMARKER REPRODUCIBILITY BEFORE THEY CAN FIND APPLICATIONS IN PRIMARY CARE AND PUBLIC HEALTH. "OMICS" BIOMARKERS HAVE ADVANCED OUR KNOWLEDGE ON THE ETIOLOGY OF OBESITY AND ITS LINKS WITH CHRONIC DISEASES. THEY BRING SUBSTANTIAL PROMISE IN IDENTIFYING EFFECTIVE PUBLIC HEALTH STRATEGIES THAT PAVE THE WAY TOWARDS PATIENT STRATIFICATION AND PRECISION PREVENTION. 2020 12 5787 37 SPUTUM ANALYSIS: NON-INVASIVE EARLY LUNG CANCER DETECTION. LUNG CANCER IS THE LEADING CAUSE OF CANCER-RELATED DEATHS OVER THE WORLD, CHARACTERIZED BY A VERY HIGH MORTALITY RATE. MOLECULAR TECHNIQUE DEVELOPMENT TRIES TO FOCUS ON EARLY DETECTION OF CANCERS BY STUDYING MOLECULAR ALTERATIONS THAT CHARACTERIZE CANCER CELLS. WORLDWIDE LUNG CANCER RESEARCH HAS FOCUSED ON AN EVER-INCREASING NUMBER OF MOLECULAR ELEMENTS OF CARCINOGENESIS AT GENETIC, EPIGENETIC AND PROTEIN LEVELS. THE NON-INVASIVENESS IS THE CHARACTERISTIC THAT ALL CLINICAL TRIALS ON CANCER DETECTION SHOULD HAVE. ABNORMAL CHEST IMAGING AND/OR NON-SPECIFIC SYMPTOMS ARE INITIAL SIGNALS OF LUNG CANCER THAT APPEAR IN AN ADVANCED STAGE OF DISEASE. THIS FACT REPRESENTS THE CAUSE OF THE LOW 5-YEAR SURVIVAL RATE: OVER 90% OF PATIENTS DYING WITHIN 5 YEARS OF DIAGNOSIS. SINCE SMOKERS HAVE HIGHER QUANTITY OF SPUTUM CONTAINING EXFOLIATED CELLS FROM THE BRONCHIAL TREE, AND THE SPUTUM REPRESENTS THE MOST EASILY ACCESSIBLE BIOLOGICAL FLUID AND ITS COLLECTION IS NON-INVASIVE, ANALYSIS OF THIS SAMPLE REPRESENTS A GOOD AREA OF RESEARCH IN EARLY LUNG CANCER DIAGNOSIS. CONTINUED CIGARETTE SMOKING IS THE CAUSE OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), WITH AN ESTIMATED ATTRIBUTABLE RISK FACTOR EXCEEDING 80% IN SMOKING AFFECTED INDIVIDUALS. LUNG CANCER IS FOUND IN 40-70% OF PATIENTS WITH COPD, PARTICULARLY IN SEVERE DISEASE, AND IT IS A COMMON CAUSE OF DEATH IN THESE PATIENTS. A LARGE PROSPECTIVE TRIAL OF ALMOST HALF A MILLION NON-SMOKERS SHOWED AS LUNG CANCER IS ALSO COMMON IN PATIENTS WITH COPD WHO HAVE NEVER SMOKED. THIS REVIEW DESCRIBES ISSUES RELATED TO EARLY LUNG CANCER SCREENING USING NON-INVASIVE METHODS. 2013 13 666 44 BLOOD-BASED DNA METHYLATION BIOMARKERS FOR TYPE 2 DIABETES: POTENTIAL FOR CLINICAL APPLICATIONS. TYPE 2 DIABETES (T2D) IS A LEADING CAUSE OF DEATH AND DISABILITY WORLDWIDE. IT IS A CHRONIC METABOLIC DISORDER THAT DEVELOPS DUE TO AN INTERPLAY OF GENETIC, LIFESTYLE, AND ENVIRONMENTAL FACTORS. THE BIOLOGICAL ONSET OF THE DISEASE OCCURS LONG BEFORE CLINICAL SYMPTOMS DEVELOP, THUS THE SEARCH FOR EARLY DIAGNOSTIC AND PROGNOSTIC BIOMARKERS, WHICH COULD FACILITATE INTERVENTION STRATEGIES TO PREVENT OR DELAY DISEASE PROGRESSION, HAS INCREASED CONSIDERABLY IN RECENT YEARS. EPIGENETIC MODIFICATIONS REPRESENT IMPORTANT LINKS BETWEEN GENETIC, ENVIRONMENTAL AND LIFESTYLE CUES AND INCREASING EVIDENCE IMPLICATE ALTERED EPIGENETIC MARKS SUCH AS DNA METHYLATION, THE MOST CHARACTERIZED AND WIDELY STUDIED EPIGENETIC MECHANISM, IN THE PATHOGENESIS OF T2D. THIS REVIEW PROVIDES AN UPDATE OF THE CURRENT STATUS OF DNA METHYLATION AS A BIOMARKER FOR T2D. FOUR DATABASES, SCOPUS, PUBMED, COCHRANE CENTRAL, AND GOOGLE SCHOLAR WERE SEARCHED FOR STUDIES INVESTIGATING DNA METHYLATION IN BLOOD. THIRTY-SEVEN STUDIES WERE IDENTIFIED, AND ARE SUMMARIZED WITH RESPECT TO POPULATION CHARACTERISTICS, BIOLOGICAL SOURCE, AND METHOD OF DNA METHYLATION QUANTIFICATION (GLOBAL, CANDIDATE GENE OR GENOME-WIDE). WE HIGHLIGHT THAT DIFFERENTIAL METHYLATION OF THE TCF7L2, KCNQ1, ABCG1, TXNIP, PHOSPHO1, SREBF1, SLC30A8, AND FTO GENES IN BLOOD ARE REPRODUCIBLY ASSOCIATED WITH T2D IN DIFFERENT POPULATION GROUPS. THESE GENES SHOULD BE PRIORITIZED AND REPLICATED IN LONGITUDINAL STUDIES ACROSS MORE POPULATIONS IN FUTURE STUDIES. FINALLY, WE DISCUSS THE LIMITATIONS FACED BY DNA METHYLATION STUDIES, WHICH INCLUDE INCLUDING INTERPATIENT VARIABILITY, CELLULAR HETEROGENEITY, AND LACK OF ACCOUNTING FOR STUDY CONFOUNDERS. THESE LIMITATIONS AND CHALLENGES MUST BE OVERCOME BEFORE THE IMPLEMENTATION OF BLOOD-BASED DNA METHYLATION BIOMARKERS INTO A CLINICAL SETTING. WE EMPHASIZE THE NEED FOR LONGITUDINAL PROSPECTIVE STUDIES TO SUPPORT THE ROBUSTNESS OF THE CURRENT FINDINGS OF THIS REVIEW. 2018 14 2148 31 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 15 4316 37 MICRORNAS AS NON-INVASIVE DIAGNOSTIC BIOMARKERS FOR GASTRIC CANCER: CURRENT INSIGHTS AND FUTURE PERSPECTIVES. NON-INVASIVE DIAGNOSTIC BIOMARKERS MAY CONTRIBUTE TO AN EARLY IDENTIFICATION OF GASTRIC CANCER (GC) AND IMPROVE THE CLINICAL MANAGEMENT. UNFORTUNATELY, NO SENSITIVE AND SPECIFIC SCREENING BIOMARKERS ARE AVAILABLE YET AND THE CURRENTLY AVAILABLE APPROACHES ARE LIMITED BY THE NATURE OF THE DISEASE. GC IS A HETEROGENIC DISEASE WITH VARIOUS DISTINCT GENETIC AND EPIGENETIC EVENTS THAT OCCUR DURING THE MULTIFACTORIAL CASCADE OF CARCINOGENESIS. MICRORNAS (MIRNAS) ARE COMMONLY DEREGULATED IN GASTRIC MUCOSA DURING THE HELICOBACTER PYLORI INFECTION AND IN STEPWISE MANNER FROM CHRONIC GASTRITIS, THROUGH PRENEOPLASTIC CONDITIONS SUCH AS ATROPHIC GASTRITIS AND INTESTINAL METAPLASIA, TO EARLY DYSPLASIA AND INVASIVE CANCER. IDENTIFICATION OF MIRNAS IN BLOOD IN 2008 LED TO A GREAT INTEREST ON MIRNA-BASED DIAGNOSTIC, PROGNOSTIC BIOMARKERS IN GC. IN THIS REVIEW, WE PROVIDE THE MOST RECENT SYSTEMATIC REVIEW ON THE EXISTING STUDIES RELATED TO MIRNAS AS DIAGNOSTIC BIOMARKERS FOR GC. HERE, WE SYSTEMATICALLY EVALUATE 75 STUDIES RELATED TO DIFFERENTIAL EXPRESSION OF CIRCULATING MIRNAS IN GC PATIENTS AND PROVIDE NOVEL VIEW ON VARIOUS HETEROGENIC ASPECTS OF THE EXISTING DATA AND SUMMARIZE THE METHODOLOGICAL DIFFERENCES. FINALLY, WE HIGHLIGHT SEVERAL IMPORTANT ASPECTS CRUCIAL TO IMPROVE THE FUTURE TRANSLATIONAL AND CLINICAL RESEARCH IN THE FIELD. 2018 16 2015 40 EPIGENETIC BIOMARKERS IN ESOPHAGEAL CANCER. THE ABERRANT DNA METHYLATION OF TUMOR SUPPRESSOR GENES IS WELL DOCUMENTED IN ESOPHAGEAL CANCER, INCLUDING ADENOCARCINOMA (EAC) AND SQUAMOUS CELL CARCINOMA (ESCC) AS WELL AS IN BARRETT'S ESOPHAGUS (BE), A PRE-MALIGNANT CONDITION THAT IS ASSOCIATED WITH CHRONIC ACID REFLUX. BE IS A WELL-RECOGNIZED RISK FACTOR FOR THE DEVELOPMENT OF EAC, AND CONSEQUENTLY THE STANDARD OF CARE IS FOR INDIVIDUALS WITH BE TO BE PLACED IN ENDOSCOPIC SURVEILLANCE PROGRAMS AIMED AT DETECTING EARLY HISTOLOGIC CHANGES THAT ASSOCIATE WITH AN INCREASED RISK OF DEVELOPING EAC. YET BECAUSE THE ABSOLUTE RISK OF EAC IN INDIVIDUALS WITH BE IS MINIMAL, A CLINICAL NEED IN THE MANAGEMENT OF BE IS THE IDENTIFICATION OF ADDITIONAL RISK MARKERS THAT WILL INDICATE INDIVIDUALS WHO ARE AT A SIGNIFICANT ABSOLUTE RISK OF EAC SO THAT THEY MAY BE SUBJECTED TO MORE INTENSIVE SURVEILLANCE. THE BEST CURRENTLY AVAILABLE RISK MARKER IS THE DEGREE OF DYSPLASIA IN ENDOSCOPIC BIOPSIES FROM THE ESOPHAGUS; HOWEVER, THIS MARKER IS SUBOPTIMAL FOR A VARIETY OF REASONS. TO DATE, THERE ARE NO MOLECULAR BIOMARKERS THAT HAVE BEEN TRANSLATED TO WIDESPREAD CLINICAL PRACTICE. THE SEARCH FOR BIOMARKERS, INCLUDING HYPERMETHYLATED GENES, FOR EITHER THE DIAGNOSIS OF BE, EAC, OR ESCC OR FOR RISK STRATIFICATION FOR THE DEVELOPMENT OF EAC IN THOSE WITH BE IS CURRENTLY AN AREA OF ACTIVE RESEARCH. IN THIS REVIEW, WE SUMMARIZE THE STATUS OF IDENTIFIED CANDIDATE EPIGENETIC BIOMARKERS FOR BE, EAC, AND ESCC. MOST OF THESE ABERRANTLY METHYLATED GENES HAVE BEEN DESCRIBED IN THE CONTEXT OF EARLY DETECTION OR DIAGNOSTIC MARKERS; OTHERS MIGHT PROVE USEFUL FOR ESTIMATING PROGNOSIS OR PREDICTING RESPONSE TO TREATMENT. FINALLY, SPECIAL ATTENTION WILL BE PAID TO SOME OF THE CHALLENGES THAT MUST BE OVERCOME IN ORDER TO DEVELOP CLINICALLY USEFUL ESOPHAGEAL CANCER BIOMARKERS. 2014 17 6027 25 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 18 3631 33 INCORPORATING BIOMARKERS IN COPD MANAGEMENT: THE RESEARCH KEEPS GOING. GLOBALLY, CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) REMAINS A MAJOR CAUSE OF MORBIDITY AND MORTALITY, HAVING A SIGNIFICANT SOCIOECONOMIC EFFECT. SEVERAL MOLECULAR MECHANISMS HAVE BEEN RELATED TO COPD INCLUDING CHRONIC INFLAMMATION, TELOMERE SHORTENING, AND EPIGENETIC MODIFICATIONS. NOWADAYS, THERE IS AN INCREASING NEED FOR NOVEL THERAPEUTIC APPROACHES FOR THE MANAGEMENT OF COPD. THESE TREATMENT STRATEGIES SHOULD BE BASED ON FINDING THE SOURCE OF ACUTE EXACERBATION OF COPD EPISODES AND ESTIMATING THE PATIENT'S OWN RISK. THE USE OF BIOMARKERS AND THE MEASUREMENT OF THEIR LEVELS IN CONJUNCTION WITH COPD EXACERBATION RISK AND DISEASE PROGNOSIS IS CONSIDERED AN ENCOURAGING APPROACH. MANY TYPES OF COPD BIOMARKERS HAVE BEEN IDENTIFIED WHICH INCLUDE BLOOD PROTEIN BIOMARKERS, CELLULAR BIOMARKERS, AND PROTEASE ENZYMES. THEY HAVE BEEN ISOLATED FROM DIFFERENT SOURCES INCLUDING PERIPHERAL BLOOD, SPUTUM, BRONCHOALVEOLAR FLUID, EXHALED AIR, AND GENETIC MATERIAL. HOWEVER, THERE IS STILL NOT AN EXCLUSIVE BIOMARKER THAT IS USED FOR THE EVALUATION OF COPD BUT RATHER A COMBINATION OF THEM, AND THIS IS ATTRIBUTED TO DISEASE COMPLEXITY. IN THIS REVIEW, WE SUMMARIZE THE CLINICAL SIGNIFICANCE OF COPD-RELATED BIOMARKERS, THEIR ASSOCIATION WITH DISEASE OUTCOMES, AND COPD PATIENTS' MANAGEMENT. FINALLY, WE DEPICT THE VARIOUS SAMPLES THAT ARE USED FOR IDENTIFYING AND MEASURING THESE BIOMARKERS. 2022 19 2622 29 EPIGENOME-WIDE ASSOCIATION STUDIES IN ASTHMA: A SYSTEMATIC REVIEW. OBJECTIVE: ASTHMA IS A COMMON CHRONIC RESPIRATORY AIRWAY DISEASE INFLUENCED BY ENVIRONMENTAL FACTORS AND POSSIBLY THEIR INTERACTION WITH THE HUMAN GENOME CAUSING EPIGENETIC CHANGES. EPIGENOME-WIDE ASSOCIATION STUDIES (EWAS) HAVE MAINLY INVESTIGATED DNA METHYLATION AND ITS ASSOCIATION WITH DISEASE OR TRAITS, EXPOSURE FACTORS OR GENE EXPRESSION. THIS SYSTEMATIC REVIEW AIMED TO IDENTIFY ALL EWAS ASSESSING DIFFERENTIALLY METHYLATED SITES ASSOCIATED WITH ASTHMA IN HUMANS. DESIGN: STRUCTURED SYSTEMATIC LITERATURE SEARCH FOLLOWING PRISMA GUIDELINES, NEWCASTLE-OTTAWA SCALE (NOS) FOR COHORT STUDIES WAS USED FOR BIAS ASSESSMENT. DATA SOURCES: WE SEARCHED PUBMED AND EMBASE DATABASES FROM 2005 TO 2019. ELIGIBILITY CRITERIA: EPIGENOME-WIDE ASSOCIATION STUDIES TESTING ASSOCIATION BETWEEN DIFFERENTIAL METHYLATION AND ASTHMA IN HUMANS. RESULTS: OVERALL, WE IDENTIFIED 16 EWAS STUDIES COMPLYING WITH OUR SEARCH CRITERIA. TWELVE STUDIES WERE CONDUCTED ON CHILDREN, AND 10 WERE CONDUCTED ON SAMPLE SIZES <150 SUBJECTS. FOUR HUNDRED AND NINETEEN CPGS WERE REPORTED IN CHILDREN STUDIES AFTER CORRECTION FOR MULTIPLE TESTING. IN THE ADULT STUDIES, THOUSANDS OF DIFFERENTIALLY METHYLATED SITES WERE IDENTIFIED. DIFFERENTIAL METHYLATION IN INFLAMMATORY-RELATED GENES CORRELATED WITH HIGHER LEVELS OF GENE EXPRESSIONS OF INFLAMMATORY MODULATORS IN ASTHMA. DIFFERENTIALLY METHYLATED GENES ASSOCIATED WITH ASTHMA INCLUDED SMAD3, SERPINC1, PROK1, IL13, RUNX3 AND TIGIT. FORTY-ONE CPGS WERE REPLICATED AT LEAST ONCE IN BLOOD SAMPLES, AND 28 CPGS WERE REPLICATED IN NASAL SAMPLES. CONCLUSION: ALTHOUGH MANY DIFFERENTIALLY METHYLATED CPGS IN GENES KNOWN TO BE INVOLVED IN ASTHMA HAVE BEEN IDENTIFIED IN EWAS TO DATE, WE CONCLUDE THAT FURTHER STUDIES OF LARGER SAMPLE SIZES AND ANALYSES OF DIFFERENTIAL METHYLATION BETWEEN DIFFERENT PHENOTYPES ARE NEEDED IN ORDER TO COMPREHENSIVELY EVALUATE THE ROLE OF EPIGENETIC FACTORS IN THE PATHOPHYSIOLOGY AND HETEROGENEITY OF ASTHMA, AND THE POTENTIAL CLINICAL UTILITY TO PREDICT OR CLASSIFY PATIENTS WITH ASTHMA. 2019 20 5882 26 SYSTEMATIC REVIEW OF LUNG FUNCTION AND COPD WITH PERIPHERAL BLOOD DNA METHYLATION IN POPULATION BASED STUDIES. BACKGROUND: EPIGENETIC VARIATIONS IN PERIPHERAL BLOOD HAVE POTENTIAL AS BIOMARKERS FOR DISEASE. THIS SYSTEMATIC REVIEW ASSESSES THE ASSOCIATION OF LUNG FUNCTION AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) WITH DNA METHYLATION PROFILES IN PERIPHERAL BLOOD FROM POPULATION-BASED STUDIES. METHODS: ONLINE DATABASES MEDLINE, EMBASE, AND WEB OF SCIENCE WERE SEARCHED. GOOGLE SCHOLAR WAS SEARCHED TO IDENTIFY GREY LITERATURE. AFTER REMOVING DUPLICATE ARTICLES, 1155 ARTICLES WERE INDEPENDENTLY SCREENED BY TWO INVESTIGATORS. PEER REVIEWED REPORTS ON POPULATION-BASED STUDIES THAT EXAMINED PERIPHERAL BLOOD DNA METHYLATION IN PARTICIPANTS WITH MEASURED LUNG FUNCTION (FEV1, FEV1/FVC RATIO) OR KNOWN COPD STATUS WERE SELECTED FOR FULL-TEXT REVIEW. SIX ARTICLES WERE SUITABLE FOR INCLUSION. INFORMATION REGARDING STUDY CHARACTERISTICS, DESIGNS, METHODOLOGIES AND CONCLUSIONS WAS EXTRACTED. A NARRATIVE SYNTHESIS WAS PERFORMED BASED ON PUBLISHED RESULTS. RESULTS: THREE OF THE SIX ARTICLES ASSESSED THE ASSOCIATION OF COPD WITH DNA METHYLATION, AND TWO OF THESE ALSO INCLUDED ASSOCIATIONS WITH LUNG FUNCTION. OVERALL, FIVE REPORTS EXAMINED THE ASSOCIATION OF LUNG FUNCTION WITH DNA METHYLATION PROFILES. FIVE OF THE SIX ARTICLES REPORTED 'SIGNIFICANT' RESULTS. HOWEVER, NO CONSISTENT CPG SITES WERE IDENTIFIED ACROSS STUDIES FOR COPD STATUS OR LUNG FUNCTION VALUES. CONCLUSIONS: DNA METHYLATION PATTERNS IN PERIPHERAL BLOOD FROM INDIVIDUALS WITH REDUCED LUNG FUNCTION OR COPD MAY BE DIFFERENT TO THOSE IN PEOPLE WITH NORMAL LUNG FUNCTION. HOWEVER, THIS SYSTEMATIC REVIEW DID NOT FIND ANY CONSISTENT ASSOCIATIONS OF LUNG FUNCTION OR COPD WITH DIFFERENTIALLY METHYLATED CPG SITES. LARGE STUDIES WITH A LONGITUDINAL DESIGN TO ADDRESS REVERSE CAUSALITY MAY PROVE A MORE FRUITFUL AREA OF RESEARCH. TRIAL REGISTRATION: PROSPERO 2016: CRD42016037352 . 2017