1 474 101 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 2 1917 34 ENVIRONMENTAL ARSENIC EXPOSURE: FROM GENETIC SUSCEPTIBILITY TO PATHOGENESIS. MORE THAN 200 MILLION PEOPLE IN 70 COUNTRIES ARE EXPOSED TO ARSENIC THROUGH DRINKING WATER. CHRONIC EXPOSURE TO THIS METALLOID HAS BEEN ASSOCIATED WITH THE ONSET OF MANY DISEASES, INCLUDING CANCER. EPIDEMIOLOGICAL EVIDENCE SUPPORTS ITS CARCINOGENIC POTENTIAL, HOWEVER, DETAILED MOLECULAR MECHANISMS REMAIN TO BE ELUCIDATED. DESPITE THE GLOBAL MAGNITUDE OF THIS PROBLEM, NOT ALL INDIVIDUALS FACE THE SAME RISK. SUSCEPTIBILITY TO THE TOXIC EFFECTS OF ARSENIC IS INFLUENCED BY ALTERATIONS IN GENES INVOLVED IN ARSENIC METABOLISM, AS WELL AS BIOLOGICAL FACTORS, SUCH AS AGE, GENDER AND NUTRITION. MOREOVER, CHRONIC ARSENIC EXPOSURE RESULTS IN SEVERAL GENOTOXIC AND EPIGENETIC ALTERATIONS TIGHTLY ASSOCIATED WITH THE ARSENIC BIOTRANSFORMATION PROCESS, RESULTING IN AN INCREASED CANCER RISK. IN THIS REVIEW, WE: 1) REVIEW THE ROLES OF INTER-INDIVIDUAL DNA-LEVEL VARIATIONS INFLUENCING THE SUSCEPTIBILITY TO ARSENIC-INDUCED CARCINOGENESIS; 2) DISCUSS THE CONTRIBUTION OF ARSENIC BIOTRANSFORMATION TO CANCER INITIATION; 3) PROVIDE INSIGHTS INTO EMERGING RESEARCH AREAS AND THE CHALLENGES IN THE FIELD; AND 4) COMPILE A RESOURCE OF PUBLICLY AVAILABLE ARSENIC-RELATED DNA-LEVEL VARIATIONS, TRANSCRIPTOME AND METHYLATION DATA. UNDERSTANDING THE MOLECULAR MECHANISMS OF ARSENIC EXPOSURE AND ITS SUBSEQUENT HEALTH EFFECTS WILL SUPPORT EFFORTS TO REDUCE THE WORLDWIDE HEALTH BURDEN AND ENCOURAGE THE DEVELOPMENT OF STRATEGIES FOR MANAGING ARSENIC-RELATED DISEASES IN THE ERA OF PERSONALIZED MEDICINE. 2018 3 2655 38 EPIMUTAGENESIS: A PROSPECTIVE MECHANISM TO REMEDIATE ARSENIC-INDUCED TOXICITY. ARSENIC TOXICITY IS A GLOBAL ISSUE, ADDRESSED BY THE WORLD HEALTH ORGANIZATION AS ONE OF THE MAJOR NATURAL CALAMITIES FACED BY HUMANS. MORE THAN 137 MILLION INDIVIDUALS IN 70 NATIONS ARE AFFECTED BY ARSENIC MAINLY THROUGH DRINKING WATER AND ALSO THROUGH DIET. CHRONIC ARSENIC EXPOSURE LEADS TO VARIOUS TYPES OF PATHO-PHYSIOLOGICAL END POINTS IN HUMANS INCLUDING CANCERS. ARSENIC, A XENOBIOTIC SUBSTANCE, IS BIOTRANSFORMED IN THE BODY TO ITS METHYLATED SPECIES BY USING THE PHYSIOLOGICAL S-ADENOSYL METHIONINE (SAM). SAM DICTATES METHYLATION STATUS OF THE GENOME AND ARSENIC METABOLISM LEADS TO DEPLETION OF SAM LEADING TO AN EPIGENETIC DISEQUILIBRIUM. SINCE EPIGENETICS IS ONE OF THE MAJOR PHENOMENON AT THE INTERFACE BETWEEN THE ENVIRONMENT AND HUMAN HEALTH IMPACT, ITS DISEQUILIBRIUM BY ARSENIC INFLICTS UPON THE CHROMATIN COMPACTION, GENE EXPRESSION, GENOMIC STABILITY AND A HOST OF BIOMOLECULAR INTERACTIONS, THE INTERACTOME WITHIN THE CELL. SINCE ARSENIC IS NOT MUTAGENIC BUT IS CARCINOGENIC IN NATURE, ARSENIC INDUCED EPIMUTAGENESIS HAS COME TO THE FOREFRONT SINCE IT DETERMINES THE TRANSCRIPTIONAL AND GENOMIC INTEGRITY OF THE CELL. ARSENIC TOXICITY BRINGS FORTH SEVERAL PATHOPHYSIOLOGICAL MANIFESTATIONS LIKE DERMATOLOGICAL NON-CANCEROUS, PRE-CANCEROUS AND CANCEROUS LESIONS, PERIPHERAL NEUROPATHY, DNA DAMAGE, RESPIRATORY DISORDERS AND CANCERS OF SEVERAL INTERNAL ORGANS. RECENTLY, SEVERAL DISEASES OF SIMILAR MANIFESTATIONS HAVE BEEN EXPLAINED WITH THE RELEVANT EPIGENETIC PERSPECTIVES REGARDING THE POSSIBLE MOLECULAR MECHANISM FOR THEIR ONSET. HENCE, IN THE CURRENT REVIEW, WE COMPREHENSIVELY TRY TO INTERCALATE THE INFORMATION ON ARSENIC-INDUCED EPIGENETIC ALTERATIONS OF DNA, HISTONES AND MICRORNA SO AS TO UNDERSTAND WHETHER THE ARSENIC-INDUCED TOXIC MANIFESTATIONS ARE BROUGHT ABOUT BY THE EPIGENETIC CHANGES. WE HIGHLIGHT THE NEED TO UNDERSTAND THE ASPECT OF EPIMUTAGENESIS AND SUBSEQUENT ALTERATIONS IN THE CELLULAR INTERACTOME DUE TO ARSENIC-INDUCED MOLECULAR CHANGES, WHICH MAY BE UTILIZED TO DEVELOP PUTATIVE THERAPEUTIC STRATEGIES TARGETING BOTH OXIDATIVE POTENTIAL AND EPIMUTAGENESIS IN HUMANS. 2015 4 4840 29 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 5 3210 35 HEALTH EFFECTS ASSOCIATED WITH PRE- AND PERINATAL EXPOSURE TO ARSENIC. INORGANIC ARSENIC IS A WELL-ESTABLISHED HUMAN CARCINOGEN, ABLE TO INDUCE GENETIC AND EPIGENETIC ALTERATIONS. MORE THAN 200 MILLION PEOPLE WORLDWIDE ARE EXPOSED TO ARSENIC CONCENTRATIONS IN DRINKING WATER EXCEEDING THE RECOMMENDED WHO THRESHOLD (10MUG/L). ADDITIONALLY, CHRONIC EXPOSURE TO LEVELS BELOW THIS THRESHOLD IS KNOWN TO RESULT IN LONG-TERM HEALTH EFFECTS IN HUMANS. THE ARSENIC-RELATED HEALTH EFFECTS IN HUMANS ARE ASSOCIATED WITH ITS BIOTRANSFORMATION PROCESS, WHEREBY THE RESULTING METABOLITES CAN INDUCE MOLECULAR DAMAGE THAT ACCUMULATES OVER TIME. THE EFFECTS DERIVED FROM THESE ALTERATIONS INCLUDE GENOMIC INSTABILITY ASSOCIATED WITH OXIDATIVE DAMAGE, ALTERATION OF GENE EXPRESSION (INCLUDING CODING AND NON-CODING RNAS), GLOBAL AND LOCALIZED EPIGENETIC REPROGRAMMING, AND HISTONE POSTTRANSLATIONAL MODIFICATIONS. THESE ALTERATIONS DIRECTLY AFFECT MOLECULAR PATHWAYS INVOLVED IN THE ONSET AND PROGRESSION OF MANY CONDITIONS THAT CAN ARISE EVEN DECADES AFTER THE EXPOSURE OCCURS. IMPORTANTLY, ARSENIC METABOLITES GENERATED DURING ITS BIOTRANSFORMATION CAN ALSO PASS THROUGH THE PLACENTAL BARRIER, RESULTING IN FETAL EXPOSURE TO THIS CARCINOGEN AT SIMILAR LEVELS TO THOSE OF THE MOTHER. AS SUCH, MORE IMMEDIATE EFFECTS OF THE ARSENIC-INDUCED MOLECULAR DAMAGE CAN BE OBSERVED AS DETRIMENTAL EFFECTS ON FETAL DEVELOPMENT, PREGNANCY, AND BIRTH OUTCOMES. IN THIS REVIEW, WE FOCUS ON THE GENETIC AND EPIGENETIC DAMAGE ASSOCIATED WITH EXPOSURE TO LOW LEVELS OF ARSENIC, PARTICULARLY THOSE AFFECTING EARLY DEVELOPMENTAL STAGES. WE ALSO PRESENT HOW THESE ALTERATIONS OCCURRING DURING EARLY LIFE CAN IMPACT THE DEVELOPMENT OF CERTAIN DISEASES IN ADULT LIFE. 2021 6 6833 18 [HYPOTHETICAL LINK BETWEEN ENDOMETRIOSIS AND XENOBIOTICS-ASSOCIATED GENETICALLY MODIFIED FOOD]. ENDOMETRIOSIS IS AN OESTROGEN-DEPENDENT INFLAMMATORY DISEASE AFFECTING 10 % OF REPRODUCTIVE-AGED WOMEN. OFTEN ACCOMPANIED BY CHRONIC PELVIC PAIN AND INFERTILITY, ENDOMETRIOSIS RIGOROUSLY INTERFERES WITH WOMEN'S QUALITY OF LIFE. ALTHOUGH THE PATHOPHYSIOLOGY OF ENDOMETRIOSIS REMAINS UNCLEAR, A GROWING BODY OF EVIDENCE POINTS TO THE IMPLICATION OF ENVIRONMENTAL TOXICANTS. OVER THE LAST DECADE, AN INCREASE IN THE INCIDENCE OF ENDOMETRIOSIS HAS BEEN REPORTED AND COINCIDES WITH THE INTRODUCTION OF GENETICALLY MODIFIED FOODS IN OUR DIET. EVEN THOUGH ASSESSMENTS OF GENETICALLY MODIFIED FOOD RISK HAVE NOT INDICATED ANY HAZARD ON HUMAN HEALTH, XENOBIOTICS-ASSOCIATED GENETICALLY MODIFIED FOOD, SUCH AS PESTICIDES RESIDUES AND XENOPROTEINS, COULD BE HARMFUL IN THE LONG-TERM. THE "LOW-DOSE HYPOTHESIS", ACCUMULATION AND BIOTRANSFORMATION OF PESTICIDES-ASSOCIATED GENETICALLY MODIFIED FOOD AND THE MULTIPLIED TOXICITY OF PESTICIDES-FORMULATION ADJUVANTS SUPPORT THIS HYPOTHESIS. THIS REVIEW SUMMARIZES TOXIC EFFECTS (IN VITRO AND ON ANIMAL MODELS) OF SOME XENOBIOTICS-ASSOCIATED GENETICALLY MODIFIED FOOD, SUCH AS GLYPHOSATE AND CRY1AB PROTEIN, AND EXTRAPOLATES ON THEIR POTENTIAL ROLE IN THE PATHOPHYSIOLOGY OF ENDOMETRIOSIS. THEIR ROLES AS IMMUNE TOXICANTS, PRO-OXIDANTS, ENDOCRINE DISRUPTORS AND EPIGENETIC MODULATORS ARE DISCUSSED. 2010 7 3775 32 INTERACTIONS BETWEEN ARSENIC-INDUCED TOXICITY AND NUTRITION IN EARLY LIFE. EXPOSURE TO ARSENIC THROUGH DRINKING WATER IS A MAJOR PUBLIC HEALTH PROBLEM AFFECTING MOST COUNTRIES, ALTHOUGH THE SITUATION IS PARTICULARLY SEVERE IN LOW-INCOME NATIONS. THE HEALTH CONSEQUENCES OF CHRONIC ARSENIC EXPOSURE INCLUDE INCREASED RISK FOR VARIOUS FORMS OF CANCER AND NUMEROUS NONCANCER EFFECTS, INCLUDING DIABETES, SKIN DISEASES, CHRONIC COUGH, AND TOXIC EFFECTS ON LIVER, KIDNEY, CARDIOVASCULAR SYSTEM, AND PERIPHERAL AND CENTRAL NERVOUS SYSTEMS. IN RECENT YEARS INCREASING REPORTS OF EFFECTS ON FETAL AND CHILD DEVELOPMENT HAVE APPEARED. THERE SEEMS TO BE A WIDE VARIATION IN SUSCEPTIBILITY TO ARSENIC TOXICITY, WHICH IS LIKELY TO BE RELATED TO FACTORS SUCH AS VARIATION IN ARSENIC METABOLISM, NUTRITION, HOST-RELATED DEFENSE MECHANISMS, AND GENETIC PREDISPOSITION. THE MAIN MECHANISMS OF ARSENIC-NUTRITION INTERACTIONS INCLUDE ARSENIC-INDUCED OXIDATIVE STRESS, WHICH REQUIRES NUTRIENT-DEPENDENT DEFENSE SYSTEMS, AND ARSENIC METABOLISM (METHYLATION) VIA 1-CARBON METABOLISM, WHICH REQUIRES METHYL GROUPS, FOLIC ACID, VITAMIN B-12, AND BETAINE FOR THE REMETHYLATION OF HOMOCYSTEINE TO METHIONINE. AN EFFICIENT FIRST METHYLATION STEP IN COMBINATION WITH A SLOW SECOND METHYLATION STEP SEEMS TO BE MOST CRITICAL FROM A TOXICOLOGICAL POINT OF VIEW. A THIRD MODE OF ARSENIC-NUTRITION INTERACTION INVOLVES EPIGENETIC EFFECTS AND FETAL PROGRAMMING VIA DNA METHYLATION. 2007 8 633 30 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 9 2961 34 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 10 6406 21 THE SEARCH FOR RELIABLE BIOMARKERS OF DISEASE IN MULTIPLE CHEMICAL SENSITIVITY AND OTHER ENVIRONMENTAL INTOLERANCES. WHILST FACING A WORLDWIDE FAST INCREASE OF FOOD AND ENVIRONMENTAL ALLERGIES, THE MEDICAL COMMUNITY IS ALSO CONFRONTED WITH ANOTHER INHOMOGENEOUS GROUP OF ENVIRONMENT-ASSOCIATED DISABLING CONDITIONS, INCLUDING MULTIPLE CHEMICAL SENSITIVITY (MCS), FIBROMYALGIA, CHRONIC FATIGUE SYNDROME, ELECTRIC HYPERSENSITIVITY, AMALGAM DISEASE AND OTHERS. THESE SHARE THE FEATURES OF POLY-SYMPTOMATIC MULTI-ORGAN CUTANEOUS AND SYSTEMIC MANIFESTATIONS, WITH POSTULATED INHERITED/ACQUIRED IMPAIRED METABOLISM OF CHEMICAL/PHYSICAL/NUTRITIONAL XENOBIOTICS, TRIGGERING ADVERSE REACTIONS AT EXPOSURE LEVELS FAR BELOW TOXICOLOGICALLY-RELEVANT VALUES, OFTEN IN THE ABSENCE OF CLEAR-CUT ALLERGOLOGIC AND/OR IMMUNOLOGIC INVOLVEMENT. DUE TO THE LACK OF PROVEN PATHOGENIC MECHANISMS GENERATING MEASURABLE DISEASE BIOMARKERS, THESE ENVIRONMENTAL HYPERSENSITIVITIES ARE GENERALLY IGNORED BY SANITARY AND SOCIAL SYSTEMS, AS PSYCHOGENIC OR "MEDICALLY UNEXPLAINED SYMPTOMS". THE UNCONTROLLED APPLICATION OF DIAGNOSTIC AND TREATMENT PROTOCOLS NOT CORRESPONDING TO ACCEPTABLE LEVELS OF VALIDATION, SAFETY, AND CLINICAL EFFICACY, TO A STEADILY INCREASING NUMBER OF PATIENTS DEMANDING ASSISTANCE, OCCURS IN MANY COUNTRIES IN THE ABSENCE OF EVIDENCE-BASED GUIDELINES. HERE WE REVISE AVAILABLE INFORMATION SUPPORTING THE ORGANIC NATURE OF THESE CLINICAL CONDITIONS. FOLLOWING INTENSE RESEARCH ON GENE POLYMORPHISMS OF PHASE I/II DETOXIFICATION ENZYME GENES, SO FAR STATISTICALLY INCONCLUSIVE, EPIGENETIC AND METABOLIC FACTORS ARE UNDER INVESTIGATION, IN PARTICULAR FREE RADICAL/ANTIOXIDANT HOMEOSTASIS DISTURBANCES. THE FINDING OF RELEVANT ALTERATIONS OF CATALASE, GLUTATHIONE-TRANSFERASE AND PEROXIDASE DETOXIFYING ACTIVITIES SIGNIFICANTLY CORRELATING WITH CLINICAL MANIFESTATIONS OF MCS, HAS RECENTLY REGISTERED SOME PROGRESS TOWARDS THE IDENTIFICATION OF RELIABLE BIOMARKERS OF DISEASE ONSET, PROGRESSION, AND TREATMENT OUTCOMES. 2011 11 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 12 1157 21 CONTAMINANT METALS AS CARDIOVASCULAR RISK FACTORS: A SCIENTIFIC STATEMENT FROM THE AMERICAN HEART ASSOCIATION. EXPOSURE TO ENVIRONMENTAL POLLUTANTS IS LINKED TO INCREASED RISK OF CARDIOVASCULAR DISEASE. BEYOND THE EXTENSIVE EVIDENCE FOR PARTICULATE AIR POLLUTION, ACCUMULATING EVIDENCE SUPPORTS THAT EXPOSURE TO NONESSENTIAL METALS SUCH AS LEAD, CADMIUM, AND ARSENIC IS A SIGNIFICANT CONTRIBUTOR TO CARDIOVASCULAR DISEASE WORLDWIDE. HUMANS ARE EXPOSED TO METALS THROUGH AIR, WATER, SOIL, AND FOOD AND EXTENSIVE INDUSTRIAL AND PUBLIC USE. CONTAMINANT METALS INTERFERE WITH CRITICAL INTRACELLULAR REACTIONS AND FUNCTIONS LEADING TO OXIDATIVE STRESS AND CHRONIC INFLAMMATION THAT RESULT IN ENDOTHELIAL DYSFUNCTION, HYPERTENSION, EPIGENETIC DYSREGULATION, DYSLIPIDEMIA, AND CHANGES IN MYOCARDIAL EXCITATION AND CONTRACTILE FUNCTION. LEAD, CADMIUM, AND ARSENIC HAVE BEEN LINKED TO SUBCLINICAL ATHEROSCLEROSIS, CORONARY ARTERY STENOSIS, AND CALCIFICATION AS WELL AS TO INCREASED RISK OF ISCHEMIC HEART DISEASE AND STROKE, LEFT VENTRICULAR HYPERTROPHY AND HEART FAILURE, AND PERIPHERAL ARTERY DISEASE. EPIDEMIOLOGICAL STUDIES SHOW THAT EXPOSURE TO LEAD, CADMIUM, OR ARSENIC IS ASSOCIATED WITH CARDIOVASCULAR DEATH MOSTLY ATTRIBUTABLE TO ISCHEMIC HEART DISEASE. PUBLIC HEALTH MEASURES REDUCING METAL EXPOSURE ARE ASSOCIATED WITH REDUCTIONS IN CARDIOVASCULAR DISEASE DEATH. POPULATIONS OF COLOR AND LOW SOCIOECONOMIC MEANS ARE MORE COMMONLY EXPOSED TO METALS AND THEREFORE AT GREATER RISK OF METAL-INDUCED CARDIOVASCULAR DISEASE. TOGETHER WITH STRENGTHENING PUBLIC HEALTH MEASURES TO PREVENT METAL EXPOSURES, DEVELOPMENT OF MORE SENSITIVE AND SELECTIVE MEASUREMENT MODALITIES, CLINICAL MONITORING OF METAL EXPOSURES, AND THE DEVELOPMENT OF METAL CHELATION THERAPIES COULD FURTHER DIMINISH THE BURDEN OF CARDIOVASCULAR DISEASE ATTRIBUTABLE TO METAL EXPOSURE. 2023 13 5361 22 RECENT ADVANCES IN ARSENIC RESEARCH: SIGNIFICANCE OF DIFFERENTIAL SUSCEPTIBILITY AND SUSTAINABLE STRATEGIES FOR MITIGATION. ARSENIC CONTAMINATION IN DRINKING WATER AND ASSOCIATED ADVERSE OUTCOMES ARE ONE OF THE MAJOR HEALTH ISSUES IN MORE THAN 50 COUNTRIES WORLDWIDE. THE SCENARIO IS GETTING EVEN MORE DETRIMENTAL WITH INCREASING NUMBER OF AFFECTED PEOPLE AND NEWER SITES REPORTED FROM ALL OVER THE WORLD. APART FROM DRINKING WATER, THE PRESENCE OF ARSENIC HAS BEEN FOUND IN VARIOUS OTHER DIETARY SOURCES. CHRONIC ARSENIC TOXICITY AFFECTS MULTIPLE PHYSIOLOGICAL SYSTEMS AND MAY CAUSE MALIGNANCIES LEADING TO DEATH. EXPOSED INDIVIDUALS, RESIDING IN THE SAME AREA, DEVELOPED DIFFERENTIAL DERMATOLOGICAL LESION PHENOTYPES AND VARIED SUSCEPTIBILITY TOWARD VARIOUS OTHER ARSENIC-INDUCED DISEASE RISK, EVEN AFTER CONSUMING EQUIVALENT AMOUNT OF ARSENIC FROM THE SIMILAR SOURCE, OVER THE SAME DURATION OF TIME. RESEARCHES SO FAR INDICATE THAT DIFFERENTIAL SUSCEPTIBILITY PLAYS AN IMPORTANT ROLE IN ARSENIC-INDUCED DISEASE MANIFESTATION. IN THIS COMPREHENSIVE REVIEW, WE HAVE IDENTIFIED MAJOR POPULATION-BASED STUDIES OF THE LAST 20 YEARS, INDICATING POSSIBLE CAUSES OF DIFFERENTIAL SUSCEPTIBILITY EMPHASIZING ARSENIC METHYLATION CAPACITY, VARIATION IN HOST GENOME (SINGLE NUCLEOTIDE POLYMORPHISM), AND INDIVIDUAL EPIGENETIC PATTERN (DNA METHYLATION, HISTONE MODIFICATION, AND MIRNA EXPRESSION). HOLISTIC MULTIDISCIPLINARY STRATEGIES NEED TO BE IMPLEMENTED WITH FEW SUSTAINABLE YET COST-EFFECTIVE SOLUTIONS LIKE ALTERNATIVE WATER SOURCE, TREATMENT OF ARSENIC-CONTAMINATED WATER, NEW ADAPTATIONS IN IRRIGATION SYSTEM, SIMPLE MODIFICATIONS IN COOKING STRATEGY, AND DIETARY SUPPLEMENTATIONS TO COMBAT THIS MENACE. OUR REVIEW FOCUSES ON THE PRESENT PERSPECTIVES OF ARSENIC RESEARCH WITH SPECIAL EMPHASIS ON THE PROBABLE CAUSES OF DIFFERENTIAL SUSCEPTIBILITY TOWARD CHRONIC ARSENIC TOXICITY AND SUSTAINABLE REMEDIATION STRATEGIES. 2020 14 3511 29 IDIOPATHIC ENVIRONMENTAL INTOLERANCES (IEI): FROM MOLECULAR EPIDEMIOLOGY TO MOLECULAR MEDICINE. INHERITED OR ACQUIRED IMPAIRMENT OF XENOBIOTICS METABOLISM IS A POSTULATED MECHANISM UNDERLYING ENVIRONMENT-ASSOCIATED PATHOLOGIES SUCH AS MULTIPLE CHEMICAL SENSITIVITY, FIBROMYALGIA, CHRONIC FATIGUE SYNDROME, DENTAL AMALGAM DISEASE, AND OTHERS, ALSO COLLECTIVELY NAMED IDIOPATHIC ENVIRONMENTAL INTOLERANCES (IEI). IN VIEW OF THE POOR CURRENT KNOWLEDGE OF THEIR ETIOLOGY AND PATHOGENESIS, AND THE ABSENCE OF RECOGNISED GENETIC AND METABOLIC MARKERS OF THE DISEASES. THEY ARE OFTEN CONSIDERED "MEDICALLY UNEXPLAINED SYNDROMES",. THESE DISABLING CONDITIONS SHARE THE FEATURES OF POLYSYMPTOMATIC MULTI-ORGAN SYNDROMES, CONSIDERED BY PART OF THE MEDICAL COMMUNITY TO BE ABERRANT RESPONSES TRIGGERED BY EXPOSURE TO LOW-DOSE ORGANIC AND INORGANIC CHEMICALS AND METALS, IN CONCENTRATIONS FAR BELOW AVERAGE REFERENCE LEVELS ADMITTED FOR ENVIRONMENTAL TOXICANTS. A GENETIC PREDISPOSITION TO ALTERED BIOTRANSFORMATION OF ENVIRONMENTAL CHEMICALS, DRUGS, AND METALS, AND OF ENDOGENOUS LOW-MOLECULAR WEIGHT METABOLITES, CAUSED BY POLYMORPHISMS OF GENES CODING FOR XENOBIOTIC METABOLIZING ENZYMES, THEIR RECEPTORS AND TRANSCRIPTION FACTORS APPEARS TO BE INVOLVED IN THE SUSCEPTIBILITY TO THESE ENVIRONMENT-ASSOCIATED PATHOLOGIES, ALONG WITH EPIGENETIC FACTORS. FREE RADICAL/ANTIOXIDANT HOMEOSTASIS MAY ALSO BE HEAVILY IMPLICATED, INDIRECTLY BY AFFECTING THE REGULATION OF XENOBIOTIC METABOLIZING ENZYMES, AND DIRECTLY BY CAUSING INCREASED LEVELS OF OXIDATIVE PRODUCTS, IMPLICATED IN THE CHRONIC DAMAGE OF CELLS AND TISSUES, WHICH IS IN PART CORRELATED WITH CLINICAL SYMPTOMS. MORE SYSTEMATIC STUDIES OF MOLECULAR EPIDEMIOLOGY, TOXICO- AND PHARMACO-GENOMICS, ELUCIDATING THE MECHANISMS OF REGULATION, EXPRESSION, INDUCTION, AND ACTIVITY OF ANTIOXIDANT/DETOXIFYING ENZYMES, AND THE POSSIBLE ROLE OF INFLAMMATORY MEDIATORS, PROMISE A BETTER UNDERSTANDING OF THIS PATHOLOGICALLY INCREASED SENSITIVITY TO LOW-LEVEL CHEMICAL STIMULI, AND A SOLID BASIS FOR EFFECTIVE INDIVIDUALIZED ANTIOXIDANT- AND/OR CHELATOR-BASED TREATMENTS. 2010 15 5557 28 ROLE OF GENOMIC INSTABILITY IN ARSENIC-INDUCED CARCINOGENICITY. A REVIEW. EXPOSURE TO CHRONIC ARSENIC TOXICITY IS ASSOCIATED WITH CANCER. ALTHOUGH UNSTABLE GENOME IS A CHARACTERISTIC FEATURE OF CANCER CELLS, THE MECHANISMS LEADING TO GENOMIC INSTABILITY IN ARSENIC-INDUCED CARCINOGENESIS ARE POORLY UNDERSTOOD. WHILE THERE ARE EXCELLENT REVIEWS RELATING TO GENOMIC INSTABILITY IN GENERAL, THERE IS NO COMPREHENSIVE REVIEW PRESENTING THE MECHANISMS INVOLVED IN ARSENIC-INDUCED GENOMIC INSTABILITY. THIS REVIEW WAS UNDERTAKEN TO PRESENT THE CURRENT STATE OF RESEARCH IN THIS AREA AND TO HIGHLIGHT THE MAJOR MECHANISMS THAT MAY INVOLVED IN ARSENIC-INDUCED GENOMIC INSTABILITY LEADING TO CANCER. GENOMIC INSTABILITY IS BROADLY CLASSIFIED INTO CHROMOSOMAL INSTABILITY (CIN), PRIMARILY ASSOCIATED WITH MITOTIC ERRORS; AND MICROSATELLITE INSTABILITY (MIN), ASSOCIATED WITH DNA LEVEL INSTABILITY. ARSENIC-INDUCED GENOMIC INSTABILITY IS ESSENTIALLY MULTI-FACTORIAL IN NATURE AND INVOLVES MOLECULAR CROSS-TALK ACROSS SEVERAL CELLULAR PATHWAYS, AND IS MODULATED BY A NUMBER OF ENDOGENOUS AND EXOGENOUS FACTORS. ARSENIC AND ITS METABOLITES GENERATE OXIDATIVE STRESS, WHICH IN TURN INDUCES GENOMIC INSTABILITY THROUGH DNA DAMAGE, IRREVERSIBLE DNA REPAIR, TELOMERE DYSFUNCTION, MITOTIC ARREST AND APOPTOSIS. IN ADDITION TO GENETIC ALTERATION; EPIGENETIC REGULATION THROUGH PROMOTER METHYLATION AND MIRNA EXPRESSION ALTERS GENE EXPRESSION PROFILING LEADING TO GENOME MORE VULNERABLE AND UNSTABLE TOWARDS CANCER RISK. MOREOVER, MUTATIONS OR SILENCING OF PRO-APOPTOTIC GENES CAN LEAD TO GENOMIC INSTABILITY BY ALLOWING SURVIVAL OF DAMAGED CELLS THAT WOULD OTHERWISE DIE. ALTHOUGH A LARGE BODY OF INFORMATION IS NOW GENERATED REGARDING ARSENIC-INDUCED CARCINOGENESIS; FURTHER STUDIES EXPLORING GENOME-WIDE ASSOCIATION, ROLE OF ENVIRONMENT AND DIET ARE NEEDED FOR A BETTER UNDERSTANDING OF THE ARSENIC-INDUCED GENOMIC INSTABILITY. 2013 16 4140 16 MECHANISMS OF P-GLYCOPROTEIN ALTERATION DURING ANTICANCER TREATMENT: ROLE IN THE PHARMACOKINETIC AND PHARMACOLOGICAL EFFECTS OF VARIOUS SUBSTRATE DRUGS. IN CLINICAL PHARMACOTHERAPY, THERAPEUTIC BENEFITS AND ADVERSE EFFECTS OF MEDICINES DIFFER SUBSTANTIALLY BETWEEN INDIVIDUALS AND ARE OFTEN DETERMINED BY THEIR BLOOD LEVELS. CRITICAL REGULATORS INFLUENCING THE PHARMACOKINETICS AND PHARMACODYNAMICS OF DRUGS INCLUDE DRUG TRANSPORTERS AND DRUG-METABOLIZING ENZYMES. AMONG THESE, WE HAVE FOCUSED ON P-GLYCOPROTEIN (P-GP), A DRUG EFFLUX TRANSPORTER. A GROWING BODY OF EVIDENCE INDICATES THAT THE EXPRESSION AND FUNCTIONAL ACTIVITY OF P-GP ARE ALTERED UNDER SEVERAL PATHOLOGICAL CONDITIONS, BY EXPOSURE TO SUBSTRATE DRUGS OF P-GP, AND BY INGESTION OF CERTAIN FOODS. IN THIS CRITICAL REVIEW, WE DISCUSS THE MECHANISMS BY WHICH ANTICANCER DRUGS, MOST OF WHICH ARE P-GP SUBSTRATES, ALTER THE EXPRESSION AND FUNCTIONAL ACTIVITY OF P-GP IN TUMORS AND NORMAL TISSUES AFTER CHRONIC TREATMENT. ACCUMULATING EVIDENCE SHOWS THAT VARIOUS TRANSCRIPTION FACTORS, IN ADDITION TO EPIGENETIC AND POST-TRANSLATIONAL FACTORS, MODULATE P-GP EXPRESSION, WHICH ALTERS THE PHARMACOKINETICS AND PHARMACOLOGICAL EFFECTS OF DRUGS. THEREFORE, IT IS IMPORTANT TO CONSIDER INDIVIDUAL PATIENTS WITH REGARD TO DRUG-TAKING HISTORY, AS WELL AS LEVELS OF P-GP EXPRESSION AND FUNCTION, WHEN PROVIDING CLINICAL PHARMACOTHERAPY. 2014 17 5450 26 REPRODUCTIVE TOXICITY OF COMBINED EFFECTS OF ENDOCRINE DISRUPTORS ON HUMAN REPRODUCTION. CONFLUENCE OF ENVIRONMENTAL, GENETIC, AND LIFESTYLE VARIABLES IS RESPONSIBLE FOR DETERIORATION OF HUMAN FECUNDITY. ENDOCRINE DISRUPTORS OR ENDOCRINE DISRUPTING CHEMICALS (EDCS) MAY BE FOUND IN A VARIETY OF FOODS, WATER, AIR, BEVERAGES, AND TOBACCO SMOKE. IT HAS BEEN DEMONSTRATED IN EXPERIMENTAL INVESTIGATIONS THAT A WIDE RANGE OF ENDOCRINE DISRUPTING CHEMICALS HAVE NEGATIVE EFFECTS ON HUMAN REPRODUCTIVE FUNCTION. HOWEVER, EVIDENCE ON THE REPRODUCTIVE CONSEQUENCES OF HUMAN EXPOSURE TO ENDOCRINE DISRUPTING CHEMICALS IS SPARSE AND/OR CONFLICTING IN THE SCIENTIFIC LITERATURE. THE COMBINED TOXICOLOGICAL ASSESSMENT IS A PRACTICAL METHOD FOR ASSESSING THE HAZARDS OF COCKTAILS OF CHEMICALS, CO-EXISTING IN THE ENVIRONMENT. THE CURRENT REVIEW PROVIDES A COMPREHENSIVE OVERVIEW OF STUDIES EMPHASIZING THE COMBINED TOXICITY OF ENDOCRINE DISRUPTING CHEMICALS ON HUMAN REPRODUCTION. ENDOCRINE DISRUPTING CHEMICALS INTERACT WITH EACH OTHER TO DISRUPT THE DIFFERENT ENDOCRINE AXES, RESULTING IN SEVERE GONADAL DYSFUNCTIONS. TRANSGENERATIONAL EPIGENETIC EFFECTS HAVE ALSO BEEN INDUCED IN GERM CELLS, MOSTLY THROUGH DNA METHYLATION AND EPIMUTATIONS. SIMILARLY, AFTER ACUTE OR CHRONIC EXPOSURE TO ENDOCRINE DISRUPTING CHEMICALS COMBINATIONS, INCREASED OXIDATIVE STRESS (OS), ELEVATED ANTIOXIDANT ENZYMATIC ACTIVITY, DISRUPTED REPRODUCTIVE CYCLE, AND REDUCED STEROIDOGENESIS ARE OFTEN REPORTED CONSEQUENCES. THE ARTICLE ALSO DISCUSSES THE CONCENTRATION ADDITION (CA) AND INDEPENDENT ACTION (IA) PREDICTION MODELS, WHICH REVEAL THE IMPORTANCE OF VARIOUS SYNERGISTIC ACTIONS OF ENDOCRINE DISRUPTING CHEMICALS MIXTURES. MORE CRUCIALLY, THIS EVIDENCE-BASED STUDY ADDRESSES THE RESEARCH LIMITATIONS AND INFORMATION GAPS, AS WELL AS PARTICULARLY PRESENTS THE FUTURE RESEARCH VIEWS ON COMBINED ENDOCRINE DISRUPTING CHEMICALS TOXICITY ON HUMAN REPRODUCTION. 2023 18 480 23 ARSENIC-INDUCED CARCINOGENESIS: THE IMPACT OF MIRNA DYSREGULATION. ARSENIC IS A TOXIC METALLOID WIDELY PRESENT IN THE EARTH'S CRUST, AND IS A PROVEN HUMAN CARCINOGEN. CHRONIC ARSENIC EXPOSURE MAINLY THROUGH DRINKING WATER CAUSES SKIN, LUNG, AND URINARY BLADDER CANCERS, AND IS ASSOCIATED WITH LIVER, PROSTATE, AND KIDNEY CANCERS, CARDIOVASCULAR AND NEUROLOGICAL DISORDERS, AND DIABETES. SEVERAL MODES OF ACTION HAVE BEEN SUGGESTED IN ARSENIC CARCINOGENESIS. HOWEVER, THE MOLECULAR ETIOLOGY OF ARSENIC-INDUCED CANCER REMAINS UNCLEAR. RECENT EVIDENCE CLEARLY INDICATES THAT GENE EXPRESSION MODIFICATIONS INDUCED BY ARSENIC MAY INVOLVE EPIGENETIC ALTERATIONS, INCLUDING MIRNA DYSREGULATION. MANY MIRNAS HAVE BEEN IMPLICATED IN DIFFERENT HUMAN CANCERS AS A CONSEQUENCE OF LOSSES AND OR GAINS OF MIRNA FUNCTION THAT CONTRIBUTE TO CANCER DEVELOPMENT. PROGRESS IN IDENTIFYING MIRNA DYSREGULATION INDUCED BY ARSENIC HAS BEEN MADE USING DIFFERENT APPROACHES AND MODELS. THE PRESENT REVIEW DISCUSSES THE RECENT DATA REGARDING DYSREGULATED EXPRESSION OF MIRNA IN ARSENIC-INDUCED MALIGNANT TRANSFORMATION IN VITRO, GAPS IN CURRENT UNDERSTANDING AND DEFICIENCIES IN CURRENT MODELS FOR ARSENIC-INDUCED CARCINOGENESIS, AND FUTURE DIRECTIONS OF RESEARCH THAT WOULD IMPROVE OUR KNOWLEDGE REGARDING THE MECHANISMS INVOLVED IN ARSENIC-INDUCED CARCINOGENESIS. 2018 19 1993 27 EPIGENETIC AND EPITRANSCRIPTOMIC MECHANISMS OF CHROMIUM CARCINOGENESIS. HEXAVALENT CHROMIUM [CR(VI)], A GROUP I CARCINOGEN CLASSIFIED BY THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER (IARC), REPRESENTS ONE OF THE MOST COMMON OCCUPATIONAL AND ENVIRONMENTAL POLLUTANTS. THE FINDINGS FROM HUMAN EPIDEMIOLOGICAL AND LABORATORY ANIMAL STUDIES SHOW THAT LONG-TERM EXPOSURE TO CR(VI) CAUSES LUNG CANCER AND OTHER CANCER. ALTHOUGH CR(VI) IS A WELL-RECOGNIZED CARCINOGEN, THE MECHANISM OF CR(VI) CARCINOGENESIS HAS NOT BEEN WELL UNDERSTOOD. DUE TO THE FACT THAT CR(VI) UNDERGOES A SERIES OF METABOLIC REDUCTIONS ONCE ENTERING CELLS TO GENERATE REACTIVE CR METABOLITES AND REACTIVE OXYGEN SPECIES (ROS) CAUSING GENOTOXICITY, CR(VI) IS GENERALLY CONSIDERED AS A GENOTOXIC CARCINOGEN. HOWEVER, MORE AND MORE STUDIES HAVE DEMONSTRATED THAT ACUTE OR CHRONIC CR(VI) EXPOSURE ALSO CAUSES EPIGENETIC DYSREGULATIONS INCLUDING CHANGING DNA METHYLATION, HISTONE POSTTRANSLATIONAL MODIFICATIONS AND REGULATORY NON-CODING RNA (MICRORNA AND LONG NON-CODING RNA) EXPRESSIONS. MOREOVER, EMERGING EVIDENCE SHOWS THAT CR(VI) EXPOSURE IS ALSO CAPABLE OF ALTERING CELLULAR EPITRANSCRIPTOME. GIVEN THE INCREASINGLY RECOGNIZED IMPORTANCE OF EPIGENETIC AND EPITRANSCRIPTOMIC DYSREGULATIONS IN CANCER INITIATION AND PROGRESSION, IT IS BELIEVED THAT CR(VI) EXPOSURE-CAUSED EPIGENETIC AND EPITRANSCRIPTOMIC CHANGES COULD PLAY IMPORTANT ROLES IN CR(VI) CARCINOGENESIS. THE GOAL OF THIS CHAPTER IS TO REVIEW THE EPIGENETIC AND EPITRANSCRIPTOMIC EFFECTS OF CR(VI) EXPOSURE AND DISCUSS THEIR ROLES IN CR(VI) CARCINOGENESIS. BETTER UNDERSTANDING THE MECHANISM OF CR(VI) CARCINOGENESIS MAY IDENTIFY NEW MOLECULAR TARGETS FOR MORE EFFICIENT PREVENTION AND TREATMENT OF CANCER RESULTING FROM CR(VI) EXPOSURE. 2023 20 6038 17 THE CHEMICAL DEFENSIVE SYSTEM IN THE PATHOBIOLOGY OF IDIOPATHIC ENVIRONMENT-ASSOCIATED DISEASES. CHEMICAL DEFENSIVE SYSTEM CONSISTING OF BIO-SENSORING, TRANSMITTING, AND RESPONSIVE ELEMENTS HAS BEEN EVOLVED TO PROTECT MULTI-CELLULAR ORGANISMS AGAINST ENVIRONMENTAL CHEMICAL INSULTS (XENOBIOTICS) AND TO MAINTAIN HOMEOSTASIS OF ENDOGENOUS LOW MOLECULAR WEIGHT METABOLITES (ENDOBIOTICS). BOTH GENETIC AND EPIGENETIC DEFECTS OF THE SYSTEM IN ASSOCIATION WITH CARCINOGENESIS AND INDIVIDUAL SENSITIVITY TO ANTI-TUMOR THERAPIES HAVE BEEN INTENSELY STUDIED. RECENTLY, SEVERAL NON-TUMOR HUMAN PATHOLOGIES WITH EVIDENT ENVIRONMENTAL COMPONENTS SUCH AS RATHER RARE FUNCTIONAL SYNDROMES (MULTIPLE CHEMICAL SENSITIVITY, CHRONIC FATIGUE, PERSIAN GULF, AND FIBROMYALGIA NOW COLLECTIVELY LABELED AS IDIOPATHIC ENVIRONMENTAL INTOLERANCES) AND COMMON DISEASES (VITILIGO AND SYSTEMIC LUPUS ERYTHEMATOSUS) HAVE BECOME SUBJECTS OF THE RESEARCH ON THE IMPAIRED METABOLISM AND DETOXIFICATION OF XENOBIOTICS AND ENDOGENOUS TOXINS. HERE, WE COLLECTED AND CRITICALLY REVIEWED EPIDEMIOLOGICAL, GENETIC, AND BIOCHEMICAL DATA ON THE INVOLVEMENT AND POSSIBLE ROLE OF CYTOCHROME P450 SUPER FAMILY ENZYMES, GLUTATHIONE-S-TRANSFERASE ISOZYMES, CATECHOL-O-METHYL-TRANSFERASE, UDP-GLUCURONOSYL TRANSFERASES, AND PROTEINS DETOXIFYING INORGANIC AND ORGANIC PEROXIDES (CATALASE, GLUTATHIONE PEROXIDASE, AND PEROXIREDOXIN) IN THE ABOVE PATHOLOGIES. GENETIC PREDISPOSITION ASSESSED MAINLY BY SINGLE NUCLEOTIDE POLYMORPHISM AND GENE EXPRESSION ANALYSES REVEALED CORRELATIONS BETWEEN DEFECTS IN GENES ENCODING XENOBIOTIC-METABOLIZING AND/OR DETOXIFYING ENZYMES AND RISK/SEVERITY OF THESE SYNDROMES/DISEASES. PROTEOME ANALYSIS IDENTIFIED ABNORMAL EXPRESSION OF THE ENZYMES. THEIR FUNCTIONS WERE AFFECTED EPIGENETICALLY LEADING TO METABOLIC IMPAIRMENT AND, AS A CONSEQUENCE, TO THE NEGATIVE HEALTH OUTCOMES SHARED BY SOME OF THESE PATHOLOGIES. DATA OBTAINED SO FAR SUGGEST THAT DISTINCT COMPONENTS OF THE CHEMICAL DEFENSIVE SYSTEM COULD BE SUITABLE MOLECULAR TARGETS FOR FUTURE PATHOGENIC THERAPIES. 2009