1 3458 205 HYPOMETHYLATION OF LINE-1 REPEAT ELEMENTS AND GLOBAL LOSS OF DNA HYDROXYMETHYLATION IN VAPERS AND SMOKERS. THE OUTBREAK OF VAPING-RELATED SEVERE LUNG INJURIES AND DEATHS AND THE EPIDEMIC OF TEEN VAPING IN THE U.S. UNDERSCORE THE URGENT NEED FOR DETERMINING THE BIOLOGICAL CONSEQUENCES OF ELECTRONIC CIGARETTE (E-CIG) USE. WE HAVE INVESTIGATED THE ASSOCIATION BETWEEN VAPING AND EPIGENETIC CHANGES BY QUANTIFYING DNA METHYLATION LEVELS IN LONG INTERSPERSED NUCLEOTIDE ELEMENT 1 (LINE-1) AND GLOBAL DNA HYDROXYMETHYLATION (5-HMC) LEVELS AND MEASURING THE EXPRESSION LEVEL OF ENZYMES CATALYSING THE RESPECTIVE PROCESSES IN PERIPHERAL BLOOD OF EXCLUSIVE VAPERS, SMOKERS, AND CONTROLS, MATCHED FOR AGE, GENDER, AND RACE (N = 45). BOTH VAPERS AND SMOKERS SHOWED SIGNIFICANT LOSS OF METHYLATION IN LINE-1 REPEAT ELEMENTS IN COMPARISON TO CONTROLS (P = 0.00854 AND P = 0.03078, RESPECTIVELY). SIMILARLY, VAPERS AND SMOKERS HAD SIGNIFICANT REDUCTIONS IN 5-HMC LEVELS RELATIVE TO CONTROLS (P = 0.04884 AND P = 0.0035, RESPECTIVELY). NEITHER THE LINE-1 METHYLATION LEVELS NOR THE GLOBAL 5-HMC LEVELS WERE DIFFERENT BETWEEN VAPERS AND SMOKERS. THERE WAS A DIRECT CORRELATION BETWEEN METHYLATION LEVELS IN THE LINE-1 ELEMENTS AND GLOBAL 5-HMC LEVELS IN THE STUDY SUBJECTS (R = 0.31696, P = 0.03389). INVERSE AND STATISTICALLY SIGNIFICANT CORRELATIONS WERE FOUND BETWEEN BOTH THE LINE-1 METHYLATION LEVELS AND THE GLOBAL 5-HMC LEVELS AND VARIOUS VAPING/SMOKING METRICS IN THE STUDY SUBJECTS. THERE WERE MODEST BUT NOT STATISTICALLY SIGNIFICANT CHANGES IN TRANSCRIPTION OF DNA METHYLTRANSFERASES AND TEN-ELEVEN TRANSLOCATION ENZYMES IN BOTH VAPERS AND SMOKERS RELATIVE TO CONTROLS. OUR FINDINGS SUPPORT FOLLOW-UP GENOME-WIDE INVESTIGATIONS INTO THE EPIGENETIC EFFECTS OF VAPING, WHICH MAY FURTHER CLARIFY THE HEALTH CONSEQUENCES OF E-CIG USE. ABBREVIATIONS: 5-MC: 5-METHYLCYTOSINE; 5-HMC: 5-HYDROXYMETHYLCYTOSINE; 8-OHDG: 8-HYDROXY-2'-DEOXYGUANOSINE; ACTIN: ACTIN BETA; ANOVA: ANALYSIS OF VARIANCE; BER: BASE EXCISION REPAIR; BMI: BODY MASS INDEX; CO: CARBON MONOXIDE; COHB: CARBOXYHAEMOGLOBIN; COBRA: COMBINED BISULPHITE RESTRICTION ANALYSIS; COPD: CHRONIC OBSTRUCTIVE PULMONARY DISEASE; DNMT1: DNA METHYLTRANSFERASE 1; DNMT3A: DNA METHYLTRANSFERASE 3A; DNMT3B: DNA METHYLTRANSFERASE 3B; E-CIGS: ELECTRONIC CIGARETTES; ELISA: ENZYME-LINKED IMMUNOSORBENT ASSAY; ENDS: ELECTRONIC NICOTINE DELIVERY SYSTEMS; FDA: FOOD AND DRUG ADMINISTRATION; GAPDH; GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; HPLC: HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; LINE-1: LONG INTERSPERSED NUCLEOTIDE ELEMENT 1; PBS: PHOSPHATE-BUFFERED SALINE; RFU: RELATIVE FLUORESCENCE UNITS; RT-QPCR: QUANTITATIVE REVERSE-TRANSCRIPTION POLYMERASE CHAIN REACTION; ROS: REACTIVE OXYGEN SPECIES; SAM, S-ADENOSYLMETHIONINE; SE: STANDARD ERROR; TET1: TEN-ELEVEN TRANSLOCATION 1; TET2: TEN-ELEVEN TRANSLOCATION 2; TET3: TEN-ELEVEN TRANSLOCATION 3. 2020 2 24 29 8-OXOGUANINE DNA GLYCOSYLASE-1-DRIVEN DNA BASE EXCISION REPAIR: ROLE IN ASTHMA PATHOGENESIS. PURPOSE OF REVIEW: TO PROVIDE BOTH AN OVERVIEW AND EVIDENCE OF THE POTENTIAL CAUSE OF OXIDATIVE DNA BASE DAMAGE AND REPAIR SIGNALING IN CHRONIC INFLAMMATION AND HISTOLOGICAL CHANGES ASSOCIATED WITH ASTHMA. RECENT FINDINGS: ASTHMA IS INITIATED/MAINTAINED BY IMMUNOLOGICAL, GENETIC/EPIGENETIC, AND ENVIRONMENTAL FACTORS. IT IS A WORLD-WIDE HEALTH PROBLEM, AS CURRENT THERAPIES SUPPRESS SYMPTOMS RATHER THAN PREVENT/REVERSE THE DISEASE, LARGELY DUE TO GAPS IN UNDERSTANDING ITS MOLECULAR MECHANISMS. INFLAMMATION, OXIDATIVE STRESS, AND DNA DAMAGE ARE INSEPARABLE PHENOMENA, BUT THEIR MOLECULAR ROLES IN ASTHMA PATHOGENESIS ARE UNCLEAR. IT WAS FOUND THAT AMONG OXIDATIVELY MODIFIED DNA BASES, 8-OXOGUANINE (8-OXOG) IS ONE OF THE MOST ABUNDANT, AND ITS LEVELS IN DNA AND BODY FLUIDS ARE CONSIDERED A BIOMARKER OF ONGOING ASTHMATIC PROCESSES. FREE 8-OXOG FORMS A COMPLEX WITH 8-OXOG DNA GLYCOSYLASE-1 AND ACTIVATES RAS-FAMILY GTPASES THAT INDUCE GENE EXPRESSION TO MOBILIZE INNATE AND ADAPTIVE IMMUNE SYSTEMS, ALONG WITH GENES REGULATING AIRWAY HYPERPLASIA, HYPER-RESPONSIVENESS, AND LUNG REMODELING IN ATOPIC AND NONATOPIC ASTHMA. SUMMARY: DNA'S INTEGRITY MUST BE MAINTAINED TO PREVENT MUTATION, SO ITS CONTINUOUS REPAIR AND DOWNSTREAM SIGNALING 'FUEL' CHRONIC INFLAMMATORY PROCESSES IN ASTHMA AND FORM THE BASIC MECHANISM WHOSE ELUCIDATION WILL ALLOW THE DEVELOPMENT OF NEW DRUG TARGETS FOR THE PREVENTION/REVERSAL OF LUNG DISEASES. 2015 3 210 28 ACTIVE DNA DEMETHYLATION IN POST-MITOTIC NEURONS: A REASON FOR OPTIMISM. OVER THE LAST SEVERAL YEARS PROTEINS INVOLVED IN BASE EXCISION REPAIR (BER) HAVE BEEN IMPLICATED IN ACTIVE DNA DEMETHYLATION. WE REVIEW THE LITERATURE SUPPORTING BER AS A MEANS OF ACTIVE DNA DEMETHYLATION, AND EXPLAIN HOW THE VARIOUS COMPONENTS FUNCTION AND COOPERATE TO REMOVE THE POTENTIALLY MOST ENDURING MEANS OF EPIGENETIC GENE REGULATION. RECENT EVIDENCE INDICATES THAT THE SAME PATHWAYS IMPLICATED DURING PERIODS OF WIDESPREAD DNA DEMETHYLATION, SUCH AS THE ERASURE OF METHYL MARKS IN THE PATERNAL PRONUCLEUS SOON AFTER FERTILIZATION, ARE OPERATIONAL IN POST-MITOTIC NEURONS. NEURONAL FUNCTIONAL IDENTITIES, DEFINED HERE AS THE RESULT OF A COMBINATION OF NEURONAL SUBTYPE, LOCATION, AND SYNAPTIC CONNECTIONS ARE LARGELY MAINTAINED THROUGH DNA METHYLATION. CHRONIC MENTAL ILLNESSES, SUCH AS SCHIZOPHRENIA, MAY BE THE RESULT OF BOTH ALTERED NEUROTRANSMITTER LEVELS AND NEURONS THAT HAVE ASSUMED DYSFUNCTIONAL NEURONAL IDENTITIES. A LIMITATION OF MOST CURRENT PSYCHOPHARMACOLOGICAL AGENTS IS THEIR FOCUS ON THE FORMER, WHILE NOT ADDRESSING THE MORE PROFOUND LATTER PATHOPHYSIOLOGICAL PROCESS. PREVIOUSLY, IT WAS BELIEVED THAT ACTIVE DNA DEMETHYLATION IN POST-MITOTIC NEURONS WAS RARE IF NOT IMPOSSIBLE. IF THIS WERE THE CASE, THEN REVERSING THE FACTORS THAT MAINTAIN NEURONAL IDENTITY, WOULD BE HIGHLY UNLIKELY. THE EMERGENCE OF AN ACTIVE DNA DEMETHYLATION PATHWAY IN THE BRAIN IS A REASON FOR GREAT OPTIMISM IN PSYCHIATRY AS IT PROVIDES A MEANS BY WHICH PREVIOUSLY PATHOLOGICAL NEURONS MAY BE REPROGRAMMED TO SERVE A MORE FAVORABLE ROLE. AGENTS TARGETING EPIGENETIC PROCESSES HAVE SHOWN MUCH PROMISE IN THIS REGARD, AND MAY LEAD TO SUBSTANTIAL GAINS OVER TRADITIONAL PHARMACOLOGICAL APPROACHES. 2013 4 1664 22 DOWNREGULATION OF GADD45BETA EXPRESSION BY HEPATITIS C VIRUS LEADS TO DEFECTIVE CELL CYCLE ARREST. MEMBERS OF THE GADD45 FAMILY PLAY CENTRAL ROLES IN THE CELLULAR RESPONSE TO GENOTOXIC STRESS AND HAVE BEEN IMPLICATED IN SEVERAL HUMAN CANCERS, INCLUDING HEPATOCELLULAR CARCINOMAS. CHRONIC INFECTION BY HEPATITIS C VIRUS (HCV) IS A MAJOR RISK FACTOR FOR THE ONSET AND DEVELOPMENT OF PRIMARY HEPATOCELLULAR TUMORS, ALTHOUGH THE UNDERLYING MECHANISMS ARE UNCLEAR. HERE, WE SHOW A NOVEL LINK BETWEEN DIMINISHED GADD45BETA EXPRESSION AND HCV INFECTION. INHIBITED GADD45BETA EXPRESSION WAS OBSERVED IN BOTH NONTUMORAL AND TUMORAL TISSUES FROM INFECTED INDIVIDUALS, AND IN CELL LINES HARBORING A HCV REPLICON AND THE INFECTIOUS HCV STRAIN JFH1. DECREASED GADD45BETA EXPRESSION WAS CONFIRMED IN VIVO IN A TRANSGENIC MURINE MODEL EXPRESSING THE ENTIRE HCV OPEN READING FRAME. MECHANISTICALLY, HYPERMETHYLATION OF THE GADD45BETA PROMOTER IN THE PRESENCE OF HCV IS RESPONSIBLE FOR THIS DEFECT. DIMINISHED GADD45BETA EXPRESSION LEADS TO ABERRANT CELL CYCLE ARREST AND DIMINISHED DNA EXCISION REPAIR. TOGETHER, THESE RESULTS PROVIDE A NOVEL INSIGHT INTO THE MECHANISMS INVOLVED IN HCV-ASSOCIATED HEPATOCELLULAR CARCINOMAS, SHOWING THAT REDUCED GADD45BETA EXPRESSION MAY PLAY A CONTRIBUTORY ROLE TO THIS PROCESS, AND PROVIDING EVIDENCE THAT HCV MAY INTERFERE WITH EPIGENETIC GENE EXPRESSION BY ALTERING PROMOTER METHYLATION. 2010 5 4374 31 MISMATCH REPAIR PROTEINS RECRUIT DNA METHYLTRANSFERASE 1 TO SITES OF OXIDATIVE DNA DAMAGE. AT SITES OF CHRONIC INFLAMMATION, EPITHELIAL CELLS ARE EXPOSED TO HIGH LEVELS OF REACTIVE OXYGEN SPECIES AND UNDERGO CANCER-ASSOCIATED DNA METHYLATION CHANGES, SUGGESTING THAT INFLAMMATION MAY INITIATE EPIGENETIC ALTERATIONS. PREVIOUSLY, WE DEMONSTRATED THAT OXIDATIVE DAMAGE CAUSES EPIGENETIC SILENCING PROTEINS TO BECOME PART OF A LARGE COMPLEX THAT IS LOCALIZED TO GC-RICH REGIONS OF THE GENOME, INCLUDING PROMOTER CPG ISLANDS THAT ARE EPIGENETICALLY SILENCED IN CANCER. HOWEVER, WHETHER THESE PROTEINS WERE RECRUITED DIRECTLY TO DAMAGED DNA OR DURING THE DNA REPAIR PROCESS WAS UNKNOWN. HERE WE DEMONSTRATE THAT THE MISMATCH REPAIR PROTEIN HETERODIMER MSH2-MSH6 PARTICIPATES IN THE OXIDATIVE DAMAGE-INDUCED RECRUITMENT OF DNA METHYLTRANSFERASE 1 (DNMT1) TO CHROMATIN. HYDROGEN PEROXIDE TREATMENT INDUCES THE INTERACTION OF MSH2-MSH6 WITH DNMT1, SUGGESTING THAT THE RECRUITMENT IS THROUGH A PROTEIN-PROTEIN INTERACTION. IMPORTANTLY, THE REDUCTION IN TRANSCRIPTION FOR GENES WITH CPG ISLAND-CONTAINING PROMOTERS CAUSED BY OXIDATIVE DAMAGE IS ABROGATED BY KNOCKDOWN OF MSH6 AND/OR DNMT1. OUR FINDINGS PROVIDE EVIDENCE THAT THE ROLE OF DNMT1 AT SITES OF OXIDATIVE DAMAGE IS TO REDUCE TRANSCRIPTION, POTENTIALLY PREVENTING TRANSCRIPTION FROM INTERFERING WITH THE REPAIR PROCESS. THIS STUDY UNIQUELY BRINGS TOGETHER SEVERAL FACTORS THAT ARE KNOWN TO CONTRIBUTE TO COLON CANCER, NAMELY INFLAMMATION, MISMATCH REPAIR PROTEINS, AND EPIGENETIC CHANGES. 2016 6 4902 20 OXIDATIVE-STRESS-INDUCED EPIGENETIC CHANGES IN CHRONIC DIABETIC COMPLICATIONS. OXIDATIVE STRESS PLAYS AN IMPORTANT ROLE IN THE DEVELOPMENT AND PROGRESSION OF CHRONIC DIABETIC COMPLICATIONS. DIABETES CAUSES MITOCHONDRIAL SUPEROXIDE OVERPRODUCTION IN THE ENDOTHELIAL CELLS OF BOTH LARGE AND SMALL VESSELS. THIS INCREASED SUPEROXIDE PRODUCTION CAUSES THE ACTIVATION OF SEVERAL SIGNAL PATHWAYS INVOLVED IN THE PATHOGENESIS OF CHRONIC COMPLICATIONS. IN PARTICULAR, ENDOTHELIAL CELLS ARE MAJOR TARGETS OF GLUCOSE-INDUCED OXIDATIVE DAMAGE IN THE TARGET ORGANS. OXIDATIVE STRESS ACTIVATES CELLULAR SIGNALING PATHWAYS AND TRANSCRIPTION FACTORS IN ENDOTHELIAL CELLS INCLUDING PROTEIN KINASE C (PKC), C-JUN-N-TERMINAL KINASE (JNK), P38 MITOGEN-ACTIVATED PROTEIN KINASE (MAPK), FORKHEAD BOX O (FOXO), AND NUCLEAR FACTOR KAPPA-B (NF-KAPPAB). OXIDATIVE STRESS ALSO CAUSES DNA DAMAGE AND ACTIVATES DNA NUCLEOTIDE EXCISION REPAIR ENZYMES INCLUDING THE EXCISION REPAIR CROSS COMPLIMENTING 1(ERCC1), ERCC4, AND POLY(ADP-RIBOSE) POLYMERASE (PARP). AUGMENTED PRODUCTION OF HISTONE ACETYLTRANSFERASE P300, AND ALTERATIONS OF HISTONE DEACETYLASES, INCLUDING CLASS III DEACETYLASES SIRTUINS, ARE ALSO INVOLVED IN THIS PROCESS. RECENT RESEARCH HAS FOUND THAT SMALL NONCODING RNAS, LIKE MICRORNA, ARE A NEW KIND OF REGULATOR ASSOCIATED WITH CHRONIC DIABETIC COMPLICATIONS. THERE ARE EXTENSIVE AND COMPLICATED INTERACTIONS AND AMONG THESE MOLECULES. THE PURPOSE OF THIS REVIEW IS TO DEMONSTRATE THE ROLE OF OXIDATIVE STRESS IN THE DEVELOPMENT OF DIABETIC COMPLICATIONS IN RELATION TO EPIGENETIC CHANGES SUCH AS ACETYLATION AND MICRORNA ALTERATIONS. 2013 7 474 23 ARSENIC BIOTRANSFORMATION AS A CANCER PROMOTING FACTOR BY INDUCING DNA DAMAGE AND DISRUPTION OF REPAIR MECHANISMS. CHRONIC EXPOSURE TO ARSENIC IN DRINKING WATER POSES A MAJOR GLOBAL HEALTH CONCERN. POPULATIONS EXPOSED TO HIGH CONCENTRATIONS OF ARSENIC-CONTAMINATED DRINKING WATER SUFFER SERIOUS HEALTH CONSEQUENCES, INCLUDING ALARMING CANCER INCIDENCE AND DEATH RATES. ARSENIC IS BIOTRANSFORMED THROUGH SEQUENTIAL ADDITION OF METHYL GROUPS, ACQUIRED FROM S-ADENOSYLMETHIONINE (SAM). METABOLISM OF ARSENIC GENERATES A VARIETY OF GENOTOXIC AND CYTOTOXIC SPECIES, DAMAGING DNA DIRECTLY AND INDIRECTLY, THROUGH THE GENERATION OF REACTIVE OXIDATIVE SPECIES AND INDUCTION OF DNA ADDUCTS, STRAND BREAKS AND CROSS LINKS, AND INHIBITION OF THE DNA REPAIR PROCESS ITSELF. SINCE SAM IS THE METHYL GROUP DONOR USED BY DNA METHYLTRANSFERASES TO MAINTAIN NORMAL EPIGENETIC PATTERNS IN ALL HUMAN CELLS, ARSENIC IS ALSO POSTULATED TO AFFECT MAINTENANCE OF NORMAL DNA METHYLATION PATTERNS, CHROMATIN STRUCTURE, AND GENOMIC STABILITY. THE BIOLOGICAL PROCESSES UNDERLYING THE CANCER PROMOTING FACTORS OF ARSENIC METABOLISM, RELATED TO DNA DAMAGE AND REPAIR, WILL BE DISCUSSED HERE. 2011 8 2099 25 EPIGENETIC EFFECTS OF LOW-LEVEL SODIUM ARSENITE EXPOSURE ON HUMAN LIVER HEPARG CELLS. CHRONIC EXPOSURE TO INORGANIC ARSENIC IS ASSOCIATED WITH A VARIETY OF ADVERSE HEALTH EFFECTS, INCLUDING LUNG, BLADDER, KIDNEY, AND LIVER CANCER. SEVERAL MECHANISMS HAVE BEEN PROPOSED FOR ARSENIC-INDUCED TUMORIGENESIS; HOWEVER, INSUFFICIENT KNOWLEDGE AND MANY UNANSWERED QUESTIONS REMAIN TO EXPLAIN THE INTEGRATED MOLECULAR PATHOGENESIS OF ARSENIC CARCINOGENICITY. IN THE PRESENT STUDY, USING NON-TUMORIGENIC HUMAN LIVER HEPARG CELLS, WE INVESTIGATED EPIGENETIC ALTERATIONS UPON PROLONGED EXPOSURE TO A NONCYTOTOXIC CONCENTRATION OF SODIUM ARSENITE (NAASO(2)). WE DEMONSTRATE THAT CONTINUOUS EXPOSURE OF HEPARG CELLS TO 1 MICROM SODIUM ARSENITE (NAASO(2)) FOR 14 DAYS RESULTED IN SUBSTANTIAL CYTOSINE DNA DEMETHYLATION AND HYPERMETHYLATION ACROSS THE GENOME, AMONG WHICH THE CLAUDIN 14 (CLDN14) GENE WAS HYPERMETHYLATED AND THE MOST DOWN-REGULATED GENE. ANOTHER IMPORTANT FINDING WAS A PROFOUND LOSS OF HISTONE H3 LYSINE 36 (H3K36) TRIMETHYLATION, WHICH WAS ACCOMPANIED BY INCREASED DAMAGE TO GENOMIC DNA AND AN ELEVATED DE NOVO MUTATION FREQUENCY. THESE RESULTS DEMONSTRATE THAT CONTINUOUS EXPOSURE OF HEPARG CELLS TO A NONCYTOTOXIC CONCENTRATION OF NAASO(2) RESULTS IN SUBSTANTIAL EPIGENETIC ABNORMALITIES ACCOMPANIED BY SEVERAL CARCINOGENESIS-RELATED EVENTS, INCLUDING INDUCTION OF EPITHELIAL-TO-MESENCHYMAL TRANSITION, DAMAGE TO DNA, INHIBITION OF DNA REPAIR GENES, AND INDUCTION OF DE NOVO MUTATIONS. IMPORTANTLY, THIS STUDY HIGHLIGHTS THE INTIMATE MECHANISTIC LINK AND INTERPLAY BETWEEN TWO FUNDAMENTAL CANCER-ASSOCIATED EVENTS, EPIGENETIC AND GENETIC ALTERATIONS, IN ARSENIC-ASSOCIATED CARCINOGENESIS. 2020 9 759 25 CASE REPORT OF CUTANEOUS SQUAMOUS CELL CARCINOMA AT THE WRIST JOINT AND THE PUBLIC HEALTH CRISIS OF ARSENICOSIS. CONTEXT: ARSENICOSIS IS CAUSED BY LONG TERM (6 MONTHS PLUS) INGESTION OF ARSENIC ABOVE A SAFE DOSE, CHARACTERIZED BY SKIN LESIONS AND POSSIBLE INVOLVEMENT OF INTERNAL ORGANS. ARSENICOSIS IS COMMON IN INDIA AND BANGLADESH WHERE NATURALLY OCCURRING HIGH CONCENTRATIONS OF ARSENIC IN THE EARTH'S CRUST CONTAMINATE GROUND WATER, CAUSING ADVERSE HEALTH EFFECTS. CASE PRESENTATION: WE REPORT A CASE OF A 55-YEAR-OLD INDIAN MALE, RESIDENT OF A KNOWN ARSENIC ENDEMIC REGION OF UTTAR PRADESH WHO SUFFERED FROM CHARACTERISTIC PULMONARY AND CUTANEOUS FEATURES OF CHRONIC ARSENIC TOXICITY WHICH INCLUDED RADIOLOGICAL FINDINGS OF INTERSTITIAL LUNG DISEASE, HYPERKERATOTIC LESIONS OVER THE PALMS AND SOLES, RAIN DROP LIKE PIGMENTATION OVER THE TRUNK, AND CARCINOMATOUS CHANGES AT THE WRIST JOINT. THE PATIENT WAS STARTED ON CHELATING AGENTS (D-PENICILLAMINE) AND ORAL RETINOIDS (ISOTRETINOIN) FOLLOWED BY THE SURGICAL EXCISION OF THE CARCINOMA. DISCUSSION: ENVIRONMENTAL CONTAMINATION WITH ARSENIC IS A WELL-KNOWN HEALTH HAZARD IN SOUTH ASIAN COUNTRIES. THE MAIN SOURCE IS CONSUMPTION OF CONTAMINATED GROUND WATER FOR DOMESTIC PURPOSES. CUTANEOUS LESIONS, INTERNAL ORGAN INVOLVEMENT INCLUDING INTERSTITIAL LUNG DISEASE AND CARCINOMAS AS OBSERVED IN OUR PATIENT HAVE BEEN REPORTED IN THE LITERATURE. VARIOUS MECHANISMS LIKE EPIGENETIC CHANGES AND ARSENIC-INDUCED IMMUNE SUPPRESSION HAVE BEEN PROPOSED FOR THE DEVELOPMENT OF CUTANEOUS CARCINOMAS WITH PROLONGED EXPOSURE TO ARSENIC. RELEVANCE TO CLINICAL PRACTICE: AMONG THE VARIOUS CAUSES OF PALMO-PLANTAR HYPERKERATOSIS, ARSENICOSIS SHOULD BE KEPT IN MIND WHEN PRESENTING IN COMBINATION WITH PIGMENTARY CHANGES AND CARCINOMATOUS GROWTH FROM AN ARSENIC-ENDEMIC REGION. CONCLUSIONS: PEOPLE RESIDING IN ARSENIC-ENDEMIC REGIONS SHOULD BE MADE AWARE OF ARSENIC-RELATED HEALTH HAZARDS. RAINWATER HARVESTING AND GOOD NUTRITION ARE THE SIMPLEST MEASURES WHICH COULD BE ADOPTED BY THE EXPOSED POPULATION IN AFFECTED AREAS. SEVERAL METHODS HAVE ALSO BEEN EMPLOYED BY GOVERNMENTAL AND NON-GOVERNMENT ORGANIZATIONS TO SEPARATE ARSENIC FROM CONTAMINATED WATER TO COMBAT ARSENIC-RELATED DISEASES AND CARCINOMAS. COMPETING INTERESTS: THE AUTHORS DECLARE NO COMPETING FINANCIAL INTERESTS. 2021 10 4840 23 ONCOGENOMIC DISRUPTIONS IN ARSENIC-INDUCED CARCINOGENESIS. CHRONIC EXPOSURE TO ARSENIC AFFECTS MORE THAN 200 MILLION PEOPLE WORLDWIDE, AND HAS BEEN ASSOCIATED WITH MANY ADVERSE HEALTH EFFECTS, INCLUDING CANCER IN SEVERAL ORGANS. THERE IS ACCUMULATING EVIDENCE THAT ARSENIC BIOTRANSFORMATION, A STEP IN THE ELIMINATION OF ARSENIC FROM THE HUMAN BODY, CAN INDUCE CHANGES AT A GENETIC AND EPIGENETIC LEVEL, LEADING TO CARCINOGENESIS. AT THE GENETIC LEVEL, ARSENIC INTERFERES WITH KEY CELLULAR PROCESSES SUCH AS DNA DAMAGE-REPAIR AND CHROMOSOMAL STRUCTURE, LEADING TO GENOMIC INSTABILITY. AT THE EPIGENETIC LEVEL, ARSENIC PLACES A HIGH DEMAND ON THE CELLULAR METHYL POOL, LEADING TO GLOBAL HYPOMETHYLATION AND HYPERMETHYLATION OF SPECIFIC GENE PROMOTERS. THESE ARSENIC-ASSOCIATED DNA ALTERATIONS RESULT IN THE DEREGULATION OF BOTH ONCOGENIC AND TUMOUR-SUPPRESSIVE GENES. FURTHERMORE, RECENT REPORTS HAVE IMPLICATED ABERRANT EXPRESSION OF NON-CODING RNAS AND THE CONSEQUENTIAL DISRUPTION OF SIGNALING PATHWAYS IN THE CONTEXT OF ARSENIC-INDUCED CARCINOGENESIS. THIS ARTICLE PROVIDES AN OVERVIEW OF THE ONCOGENOMIC ANOMALIES ASSOCIATED WITH ARSENIC EXPOSURE AND CONVEYS THE IMPORTANCE OF NON-CODING RNAS IN THE ARSENIC-INDUCED CARCINOGENIC PROCESS. 2017 11 4688 22 NEW UNDERSTANDING OF DIAGNOSIS, TREATMENT AND PREVENTION OF ENDOMETRIOSIS. FOR 100 YEARS, PELVIC ENDOMETRIOSIS HAS BEEN CONSIDERED TO ORIGINATE FROM THE IMPLANTATION OF ENDOMETRIAL CELLS FOLLOWING RETROGRADE MENSTRUATION OR METAPLASIA. SINCE SOME OBSERVATIONS, SUCH AS THE CLONAL ASPECT, THE BIOCHEMICAL VARIABILITY OF LESIONS AND ENDOMETRIOSIS IN WOMEN WITHOUT ENDOMETRIUM, THE GENETIC-EPIGENETIC (G-E) THEORY DESCRIBES THAT ENDOMETRIOSIS ONLY BEGINS AFTER A SERIES OF CUMULATIVE G-E CELLULAR CHANGES. THIS EXPLAINS THAT THE ENDOMETRIOTIC MAY ORIGINATE FROM ANY PLURIPOTENT CELL APART FROM THE ENDOMETRIUM, THAT 'ENDOMETRIUM-LIKE CELLS' CAN HARBOUR IMPORTANT G-E DIFFERENCES, AND THAT THE RISK IS HIGHER IN PREDISPOSED WOMEN WITH MORE INHERITED INCIDENTS. A CONSEQUENCE IS A HIGH RISK AFTER PUBERTY WHICH DECREASES PROGRESSIVELY THEREAFTER. CONSIDERING A 10-YEAR DELAY BETWEEN INITIATION AND PERFORMING A LAPAROSCOPY, THIS WAS OBSERVED IN THE UNITED ARAB EMIRATES, BELGIUM, FRANCE AND USA. THE SUBSEQUENT GROWTH VARIES WITH THE G-E CHANGES AND THE ENVIRONMENT BUT IS SELF-LIMITING PROBABLY BECAUSE OF THE IMMUNOLOGIC REACTION AND FIBROSIS. THAT EACH LESION HAS A DIFFERENT SET OF G-E INCIDENTS EXPLAINS THE VARIABILITY OF PAIN AND THE RESPONSE TO HORMONAL TREATMENT. NEW LESIONS MAY DEVELOP, BUT RECURRENCES AFTER SURGICAL EXCISION ARE RARE. THE FIBROSIS AROUND ENDOMETRIOSIS BELONGS TO THE BODY AND DOES NOT NEED TO BE REMOVED. THIS SUGGESTS CONSERVATIVE EXCISION OR MINIMAL BOWEL WITHOUT SAFETY MARGINS AND SUPERFICIAL TREATMENT OF OVARIAN ENDOMETRIOSIS. THIS G-E CONCEPT ALSO SUGGESTS PREVENTION BY DECREASING OXIDATIVE STRESS FROM RETROGRADE MENSTRUATION OR THE PERITONEAL MICROBIOME. THIS SUGGESTS THE PREVENTION OF VAGINAL INFECTIONS AND CHANGES IN THE GASTROINTESTINAL MICROBIOTA THROUGH FOOD INTAKE AND EXERCISE. IN CONCLUSION, A HIGHER RISK OF INITIATING ENDOMETRIOSIS DURING ADOLESCENCE WAS OBSERVED IN UAE, FRANCE, BELGIUM AND USA. THIS NEW UNDERSTANDING AND THE LIMITED GROWTH OPENS PERSPECTIVES FOR EARLIER DIAGNOSIS AND BETTER TREATMENT. 2022 12 4524 22 MULTIFACETED CONTROL OF DNA REPAIR PATHWAYS BY THE HYPOXIC TUMOR MICROENVIRONMENT. HYPOXIA, AS A PERVASIVE FEATURE IN THE MICROENVIRONMENT OF SOLID TUMORS, PLAYS A SIGNIFICANT ROLE IN CANCER PROGRESSION, METASTASIS, AND ULTIMATELY CLINICAL OUTCOME. ONE KEY CELLULAR CONSEQUENCE OF HYPOXIC STRESS IS THE REGULATION OF DNA REPAIR PATHWAYS, WHICH CONTRIBUTES TO THE GENOMIC INSTABILITY AND MUTATOR PHENOTYPE OBSERVED IN HUMAN CANCERS. TUMOR HYPOXIA CAN VARY IN SEVERITY AND DURATION, RANGING FROM ACUTE FLUCTUATING HYPOXIA ARISING FROM TEMPORARY BLOCKAGES IN THE IMMATURE MICROVASCULATURE, TO CHRONIC MODERATE HYPOXIA DUE TO SPARSE VASCULATURE, TO COMPLETE ANOXIA AT DISTANCES MORE THAN 150 MUM FROM THE NEAREST BLOOD VESSEL. PARALLELING THE INTRA-TUMOR HETEROGENEITY OF HYPOXIA, THE EFFECTS OF HYPOXIA ON DNA REPAIR OCCUR THROUGH DIVERSE MECHANISMS. ACUTELY, HYPOXIA ACTIVATES DNA DAMAGE SIGNALING PATHWAYS, PRIMARILY VIA POST-TRANSLATIONAL MODIFICATIONS. ON A LONGER TIMESCALE, HYPOXIA LEADS TO TRANSCRIPTIONAL AND/OR TRANSLATIONAL DOWNREGULATION OF MOST DNA REPAIR PATHWAYS INCLUDING DNA DOUBLE-STRAND BREAK REPAIR, MISMATCH REPAIR, AND NUCLEOTIDE EXCISION REPAIR. FURTHERMORE, EXTENDED HYPOXIA CAN LEAD TO LONG-TERM PERSISTENT SILENCING OF CERTAIN DNA REPAIR GENES, INCLUDING BRCA1 AND MLH1, REVEALING A MECHANISM BY WHICH TUMOR SUPPRESSOR GENES CAN BE INACTIVATED. THE DISCOVERIES OF THE HYPOXIC MODULATION OF DNA REPAIR PATHWAYS HAVE HIGHLIGHTED MANY POTENTIAL WAYS TO TARGET SUSCEPTIBILITIES OF HYPOXIC CANCER CELLS. IN THIS REVIEW, WE WILL DISCUSS THE MULTIFACETED HYPOXIC CONTROL OF DNA REPAIR AT THE TRANSCRIPTIONAL, POST-TRANSCRIPTIONAL, AND EPIGENETIC LEVELS, AND WE WILL OFFER PERSPECTIVE ON THE FUTURE OF ITS CLINICAL IMPLICATIONS. 2015 13 4053 18 MANAGING KELOID SCARS: FROM RADIATION THERAPY TO ACTUAL AND POTENTIAL DRUG DELIVERIES. THE AETIOLOGY OF KELOIDS IS BECOMING CLEARER, BUT MANY QUESTIONS REMAIN, INCLUDING ABOUT THE MOST OPTIMAL TREATMENT. CURRENT THERAPIES INCLUDE SURGICAL EXCISION, RADIOTHERAPY, AND VARIOUS PHARMACEUTICAL DRUGS. HOWEVER, NONE OF THESE DRUGS ARE KELOID-SPECIFIC. MOREOVER, ALL CURRENT INTERVENTIONS ARE ASSOCIATED WITH HIGH RECURRENCE RATES. HERE, WE REVIEW THE PHARMACEUTICAL INTERVENTIONS THAT ARE CURRENTLY AVAILABLE. ALL ARE BASED ON THE FACT THAT KELOIDS ARE AN EXPANDING SOLID MASS WITH INTENSE CHRONIC INFLAMMATION AT ITS ADVANCING EDGES. CONSEQUENTLY, CURRENT PHARMACEUTICALS AIM TO REDUCE THE MASS AND/OR SYMPTOMS OF KELOIDS, SIMILAR TO SURGERY AND RADIOTHERAPY. THEY INCLUDE CHEMOTHERAPIES, IMMUNOTHERAPIES, VOLUME-REDUCING THERAPIES, AND ANTI-INFLAMMATORY THERAPIES. WE ALSO DESCRIBE NEW ADVANCES IN KELOID PHARMACEUTICALS. THEY INCLUDE DRUGS THAT WERE DESIGNED TO TREAT SYSTEMIC DISEASES SUCH AS HYPERTENSION OR BREAST CANCER BUT WERE FOUND TO ALSO TREAT KELOIDS. FURTHERMORE, RECENT PROGRESS IN GENETIC, EPIGENETIC, AND STEM CELL THERAPIES SUGGESTS THAT THEY COULD BECOME USEFUL IN THE KELOID FIELD. THIS REVIEW OF PHARMACEUTICAL ADVANCES WILL HOPEFULLY PROMOTE ADDITIONAL RESEARCH AND THE DEVELOPMENT OF EFFECTIVE AND SPECIFIC PHARMACEUTICALS FOR KELOIDS. 2019 14 3865 30 JAK2 REGULATES MISMATCH REPAIR PROTEIN-MEDIATED EPIGENETIC ALTERATIONS IN RESPONSE TO OXIDATIVE DAMAGE. AT SITES OF CHRONIC INFLAMMATION EPITHELIAL CELLS UNDERGO ABERRANT DNA METHYLATION THAT CONTRIBUTES TO TUMORIGENESIS. INFLAMMATION IS ASSOCIATED WITH AN INCREASE IN REACTIVE OXYGEN SPECIES (ROS) THAT CAUSE OXIDATIVE DNA DAMAGE, WHICH HAS ALSO BEEN LINKED TO EPIGENETIC ALTERATIONS. WE PREVIOUSLY DEMONSTRATED THAT IN RESPONSE TO ROS, MISMATCH REPAIR PROTEINS MSH2 AND MSH6 RECRUIT EPIGENETIC SILENCING PROTEINS DNA METHYLTRANSFERASE 1 (DNMT1) AND POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) MEMBERS TO SITES OF DNA DAMAGE, RESULTING IN TRANSCRIPTIONAL REPRESSION OF TUMOR SUPPRESSOR GENES (TSGS). HOWEVER, IT WAS UNCLEAR WHAT SIGNAL IS UNIQUE TO ROS THAT RESULTS IN THE CHROMATIN BINDING OF MSH2 AND MSH6. HEREIN, WE DEMONSTRATE THAT IN RESPONSE TO HYDROGEN PEROXIDE (H(2) O(2) ), JAK2 LOCALIZES TO THE NUCLEUS AND INTERACTS WITH MSH2 AND MSH6. INHIBITION OR KNOCKDOWN OF JAK2 REDUCES THE H(2) O(2) -INDUCED CHROMATIN INTERACTION OF MSH2, MSH6, DNMT1, AND PRC2 MEMBERS, REDUCES H(2) O(2) -INDUCED GLOBAL INCREASE IN TRIMETHYLATION OF LYSINE 27 OF HISTONE H3 (H3K27ME3), AND ABROGATES OXIDATIVE DAMAGE-INDUCED TRANSCRIPTIONAL REPRESSION OF CANDIDATE TSGS. MOREOVER, JAK2 MRNA EXPRESSION IS ASSOCIATED WITH CPG ISLAND METHYLATOR PHENOTYPE (CIMP) STATUS IN HUMAN COLORECTAL CANCER. OUR FINDINGS PROVIDE NOVEL INSIGHT INTO THE CONNECTION BETWEEN KINASE ACTIVATION AND EPIGENETIC ALTERATIONS DURING OXIDATIVE DAMAGE AND INFLAMMATION. ENVIRON. MOL. MUTAGEN. 60:308-319, 2019. (C) 2018 WILEY PERIODICALS, INC. 2019 15 477 34 ARSENIC PROJECTS IN SE ASIA. EARLY LIFE EXPOSURE TO INORGANIC ARSENIC IS ASSOCIATED WITH A WIDE RANGE OF MALIGNANT AND CHRONIC DISEASE OUTCOMES IN HUMANS. PRENATAL ARSENIC EXPOSURE MAY GIVE RISE TO ADVERSE EFFECTS ON CHILD HEALTH AND DEVELOPMENT AS ARSENIC READILY PASSES THROUGH THE PLACENTA IN HUMAN BEINGS. THE IMPACT OF MATERNAL ARSENIC EXPOSURE ON FETAL GENE EXPRESSION WAS CONDUCTED IN PREGNANT WOMEN LIVING IN SOUTHERN THAILAND. ARSENIC EXPOSED NEWBORNS HAD SIGNIFICANTLY HIGHER LEVELS OF ARSENIC IN CORD BLOOD, AND A SET OF GENES ASSOCIATED WITH NUMEROUS BIOLOGICAL PATHWAYS, INCLUDING CELL SIGNALING, APOPTOSIS, INFLAMMATORY AND STRESS RESPONSE. A SLIGHT INCREASE IN PROMOTER METHYLATION OF P53 IN CORD BLOOD LYMPHOCYTES WHICH CORRELATED WITH ARSENIC ACCUMULATION IN NAILS WAS OBSERVED IN THESE EXPOSED NEWBORNS. A FOLLOW-UP STUDY ON THESE EXPOSED CHILDREN SHOWED A SIGNIFICANT INCREASE IN OXIDATIVE DNA DAMAGE, MEASURED AS 8-HYDROXYDEOXYGUANOSINE (8-OHDG) IN SALIVA. IN ADDITION, LEVELS OF URINARY 8-OHDG EXCRETION AND SALIVARY HOGG1 EXPRESSION WERE SIGNIFICANTLY DECREASED IN EXPOSED CHILDREN SUGGESTING A DEFECT IN REPAIR OF 8-OHDG IN ARSENIC-EXPOSED CHILDREN. OUR STUDY INDICATES THAT PRENATAL ARSENIC AND CONTINUED EXPOSURE THROUGH EARLY CHILDHOOD CAN TRIGGER VARIOUS GENETIC AND EPIGENETIC ALTERATIONS THAT MAY LEAD TO DISEASE DEVELOPMENT LATER IN LIFE. 2016 16 2961 29 GENETIC AND EPIGENETIC MECHANISMS IN METAL CARCINOGENESIS AND COCARCINOGENESIS: NICKEL, ARSENIC, AND CHROMIUM. CHRONIC EXPOSURE TO NICKEL(II), CHROMIUM(VI), OR INORGANIC ARSENIC (IAS) HAS LONG BEEN KNOWN TO INCREASE CANCER INCIDENCE AMONG AFFECTED INDIVIDUALS. RECENT EPIDEMIOLOGICAL STUDIES HAVE FOUND THAT CARCINOGENIC RISKS ASSOCIATED WITH CHROMATE AND IAS EXPOSURES WERE SUBSTANTIALLY HIGHER THAN PREVIOUSLY THOUGHT, WHICH LED TO MAJOR REVISIONS OF THE FEDERAL STANDARDS REGULATING AMBIENT AND DRINKING WATER LEVELS. GENOTOXIC EFFECTS OF CR(VI) AND IAS ARE STRONGLY INFLUENCED BY THEIR INTRACELLULAR METABOLISM, WHICH CREATES SEVERAL REACTIVE INTERMEDIATES AND BYPRODUCTS. TOXIC METALS ARE CAPABLE OF POTENT AND SURPRISINGLY SELECTIVE ACTIVATION OF STRESS-SIGNALING PATHWAYS, WHICH ARE KNOWN TO CONTRIBUTE TO THE DEVELOPMENT OF HUMAN CANCERS. DEPENDING ON THE METAL, ASCORBATE (VITAMIN C) HAS BEEN FOUND TO ACT EITHER AS A STRONG ENHANCER OR SUPPRESSOR OF TOXIC RESPONSES IN HUMAN CELLS. IN ADDITION TO GENETIC DAMAGE VIA BOTH OXIDATIVE AND NONOXIDATIVE (DNA ADDUCTS) MECHANISMS, METALS CAN ALSO CAUSE SIGNIFICANT CHANGES IN DNA METHYLATION AND HISTONE MODIFICATIONS, LEADING TO EPIGENETIC SILENCING OR REACTIVATION OF GENE EXPRESSION. IN VITRO GENOTOXICITY EXPERIMENTS AND RECENT ANIMAL CARCINOGENICITY STUDIES PROVIDED STRONG SUPPORT FOR THE IDEA THAT METALS CAN ACT AS COCARCINOGENS IN COMBINATION WITH NONMETAL CARCINOGENS. COCARCINOGENIC AND COMUTAGENIC EFFECTS OF METALS ARE LIKELY TO STEM FROM THEIR ABILITY TO INTERFERE WITH DNA REPAIR PROCESSES. OVERALL, METAL CARCINOGENESIS APPEARS TO REQUIRE THE FORMATION OF SPECIFIC METAL COMPLEXES, CHROMOSOMAL DAMAGE, AND ACTIVATION OF SIGNAL TRANSDUCTION PATHWAYS PROMOTING SURVIVAL AND EXPANSION OF GENETICALLY/EPIGENETICALLY ALTERED CELLS. 2008 17 6387 21 THE ROLE OF REACTIVE OXYGEN SPECIES IN ARSENIC TOXICITY. ARSENIC POISONING IS A GLOBAL HEALTH PROBLEM. CHRONIC EXPOSURE TO ARSENIC HAS BEEN ASSOCIATED WITH THE DEVELOPMENT OF A WIDE RANGE OF DISEASES AND HEALTH PROBLEMS IN HUMANS. ARSENIC EXPOSURE INDUCES THE GENERATION OF INTRACELLULAR REACTIVE OXYGEN SPECIES (ROS), WHICH MEDIATE MULTIPLE CHANGES TO CELL BEHAVIOR BY ALTERING SIGNALING PATHWAYS AND EPIGENETIC MODIFICATIONS, OR CAUSE DIRECT OXIDATIVE DAMAGE TO MOLECULES. ANTIOXIDANTS WITH THE POTENTIAL TO REDUCE ROS LEVELS HAVE BEEN SHOWN TO AMELIORATE ARSENIC-INDUCED LESIONS. HOWEVER, EMERGING EVIDENCE SUGGESTS THAT CONSTRUCTIVE ACTIVATION OF ANTIOXIDATIVE PATHWAYS AND DECREASED ROS LEVELS CONTRIBUTE TO CHRONIC ARSENIC TOXICITY IN SOME CASES. THIS REVIEW DETAILS THE PATHWAYS INVOLVED IN ARSENIC-INDUCED REDOX IMBALANCE, AS WELL AS CURRENT STUDIES ON PROPHYLAXIS AND TREATMENT STRATEGIES USING ANTIOXIDANTS. 2020 18 3099 33 GENOMIC DNA METHYLATION SIGNATURES IN DIFFERENT TISSUES AFTER AMBIENT AIR PARTICULATE MATTER EXPOSURE. DNA METHYLATION (5-MC) IS ONE OF THE SEVERAL EPIGENETIC MARKERS, AND IS GENERALLY ASSOCIATED WITH THE INHIBITION OF GENE EXPRESSION. BOTH HYPER AND HYPO DNA METHYLATION ARE ASSOCIATED WITH THE DISEASES. EXPOSURE TO FINE PARTICLES WITH A DIAMETER OF 2.5 MUM OR LESS (PM(2.5)) IS A PERVASIVE RISK FACTOR FOR CARDIOPULMONARY MORTALITY, METABOLIC DISORDERS, COGNITION DAMAGE, AND ETC.. RECENT REPORTS POINTED TOWARD THAT THESE DISEASES WERE ASSOCIATED WITH THE ALTERED DNA METHYLATION LEVEL OF SOME SPECIFIC-GENE, POTENTIALLY SUGGESTING THAT THE DNA METHYLATION ALTERATION WAS INVOLVED IN THE HEALTH HAZARD DERIVED FROM THE PM(2.5) EXPOSURE. IN THIS STUDY, WE SYSTEMATICALLY INVESTIGATED THE GLOBAL DNA METHYLATION LEVEL OF MOST TISSUES, INCLUDING LUNG, HEART, TESTIS, THYMUS, SPLEEN, EPIDIDYMAL FAT, HIPPOCAMPUS, KIDNEY, LIVE, AFTER SHORT AND LONG TERM PM(2.5) EXPOSURE. AFTER ACUTE PM(2.5) EXPOSURE, THE GLOBAL HYPO-METHYLATION IN DNA WAS OBSERVED IN LUNG AND HEART. NOTABLY, AFTER CHRONIC PM(2.5) EXPOSURE, LEVEL OF GLOBAL DNA METHYLATION DECREASED IN MOST ORGANS WHICH INCLUDED LUNG, TESTIS, THYMUS, SPLEEN, EPIDIDYMAL FAT, HIPPOCAMPUS AND BLOOD. THE PRESENT STUDY SYSTEMATICALLY DEMONSTRATED THE GLOBAL DNA METHYLATION CHANGES BY PM(2.5) EXPOSURE, AND PUT FORWARD A POSSIBLE ORIENTATION FOR FURTHER EXPLORING THE EFFECTS OF AMBIENT AIR PARTICLES EXPOSURE ON THE SPECIFIC ORGANS. 2019 19 2656 21 EPIMUTATION AND CANCER: A NEW CARCINOGENIC MECHANISM OF LYNCH SYNDROME (REVIEW). EPIMUTATION IS DEFINED AS ABNORMAL TRANSCRIPTIONAL REPRESSION OF ACTIVE GENES AND/OR ABNORMAL ACTIVATION OF USUALLY REPRESSED GENES CAUSED BY ERRORS IN EPIGENETIC GENE REPRESSION. EPIMUTATION ARISES IN SOMATIC CELLS AND THE GERMLINE, AND CONSTITUTIONAL EPIMUTATION MAY ALSO OCCUR. EPIMUTATION IS THE FIRST STEP OF TUMORIGENESIS AND CAN BE A DIRECT CAUSE OF CARCINOGENESIS. CANCERS ASSOCIATED WITH EPIMUTATION INCLUDE LYNCH SYNDROME (HEREDITARY NON-POLYPOSIS COLORECTAL CANCER, HNPCC), CHRONIC LYMPHOCYTIC LEUKEMIA, BREAST CANCER AND OVARIAN CANCER. EPIMUTATION HAS BEEN SHOWN FOR MANY TUMOR SUPPRESSOR GENES, INCLUDING RB, VHL, HMLH1, APC AND BRCA1, IN SPORADIC CANCERS. METHYLATION HAS RECENTLY BEEN SHOWN IN DNA FROM NORMAL TISSUES AND PERIPHERAL BLOOD IN CASES OF SPORADIC COLORECTAL CANCER AND MANY STUDIES SHOW CONSTITUTIVE EPIMUTATION IN CANCERS. EPIMUTATION OF DNA MISMATCH REPAIR (MMR) GENES (BRCA1, HMLH1 AND HMSH2) INVOLVED IN DEVELOPMENT FAMILIAL CANCERS HAS ALSO BEEN FOUND. THESE RESULTS HAVE LED TO A FOCUS ON EPIMUTATION AS A NOVEL ONCOGENIC MECHANISM. 2012 20 633 28 BIOLOGICAL EFFECTS AND EPIDEMIOLOGICAL CONSEQUENCES OF ARSENIC EXPOSURE, AND REAGENTS THAT CAN AMELIORATE ARSENIC DAMAGE IN VIVO. THROUGH CONTAMINATED DIET, WATER, AND OTHER FORMS OF ENVIRONMENTAL EXPOSURE, ARSENIC AFFECTS HUMAN HEALTH. THERE ARE MANY U.S. AND WORLDWIDE "HOT SPOTS" WHERE THE ARSENIC LEVEL IN PUBLIC WATER EXCEEDS THE MAXIMUM EXPOSURE LIMIT. THE BIOLOGICAL EFFECTS OF CHRONIC ARSENIC EXPOSURE INCLUDE GENERATION OF REACTIVE OXYGEN SPECIES (ROS), LEADING TO OXIDATIVE STRESS AND DNA DAMAGE, EPIGENETIC DNA MODIFICATION, INDUCTION OF GENOMIC INSTABILITY, AND INFLAMMATION AND IMMUNOMODULATION, ALL OF WHICH CAN INITIATE CARCINOGENESIS. HIGH ARSENIC EXPOSURE IS EPIDEMIOLOGICALLY ASSOCIATED WITH SKIN, LUNG, BLADDER, LIVER, KIDNEY AND PANCREATIC CANCER, AND CARDIOVASCULAR, NEURONAL, AND OTHER DISEASES. THIS REVIEW BRIEFLY SUMMARIZES THE BIOLOGICAL EFFECTS OF ARSENIC EXPOSURE AND EPIDEMIOLOGICAL CANCER STUDIES WORLDWIDE, AND PROVIDES AN OVERVIEW FOR EMERGING RODENT-BASED STUDIES OF REAGENTS THAT CAN AMELIORATE THE EFFECTS OF ARSENIC EXPOSURE IN VIVO. THESE REAGENTS MAY BE TRANSLATED TO HUMAN POPULATIONS FOR DISEASE PREVENTION. WE PROPOSE THE IMPORTANCE OF DEVELOPING A BIOMARKER-BASED PRECISION PREVENTION APPROACH FOR THE HEALTH ISSUES ASSOCIATED WITH ARSENIC EXPOSURE THAT AFFECTS MILLIONS OF PEOPLE WORLDWIDE. 2017