1 6908 38 [THYROID AND HEPATITIS C]. AUTOIMMUNE THYROID DISEASES ARE COMPLEX DISEASES THAT DEVELOP AS A RESULT OF INTERACTIONS BETWEEN GENETIC, EPIGENETIC AND ENVIRONMENTAL FACTORS. IFNA THERAPY OF CHRONIC HCV INFECTION IS ASSOCIATED WITH SUBCLINICAL OR CLINICAL THYROIDITIS, WHILE THE RELATIONSHIP BETWEEN THYROIDITIS AND VIRUS C INFECTION IS STILL DEBATED. 2012 2 5830 19 STRESS, THYROID DYSREGULATION, AND THYROID CANCER IN CHILDREN AND ADOLESCENTS: PROPOSED IMPENDING MECHANISMS. STRESS IS A POTENTIAL CATALYST FOR THYROID DYSREGULATION THROUGH CROSS-COMMUNICATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AND HYPOTHALAMIC-PITUITARY-THYROID (HPT) AXES. STRESS AND STRESSORS EXPOSURE MOTIVATES MOLECULAR MECHANISMS AFFECTING COMPOUND FEEDBACK LOOPS OF THE HPT AXIS. WHILE THERE IS EVIDENCE OF CONNECTION BETWEEN STRESS AND THYROID DYSREGULATION, THE QUESTION WHETHER THIS CONNECTION IS IMPLICATED IN THE DEVELOPMENT OF THYROID CANCER (TC) REMAINS UNANSWERED. IN VIEW OF THE RISING INCIDENCE OF TC IN BOTH ADULTS AND CHILDREN ALONGSIDE THE INCREASING STRESS IN OUR MODERN SOCIETY, THERE IS A NEED TO UNDERSTAND POSSIBLE INTERRELATIONS BETWEEN STRESS, THYROID DYSREGULATION, AND TC. PROLONGED GLUCOCORTICOID SECRETION DUE TO STRESS INTERFERES WITH IMMUNE SYSTEM RESPONSE BY ALTERING THE CYTOKINES, INDUCING LOW-GRADE CHRONIC INFLAMMATION, AND SUPPRESSING FUNCTION OF IMMUNE-PROTECTIVE CELLS. CHRONIC INFLAMMATION IS A RISK FACTOR LINKED TO TC. THE ROLE OF AUTOIMMUNITY HAS BEEN A MATTER OF CONTROVERSY. HOWEVER, THERE IS EPIDEMIOLOGICAL CONNECTION BETWEEN AUTOIMMUNE THYROID DISEASE (AITD) AND TC; PATIENTS WITH AITD SHOW INCREASED INCIDENCE IN PAPILLARY THYROID CARCINOMA (PTC), AND THOSE WITH TC SHOW A HIGH PREVALENCE OF INTRATHYROIDAL LYMPHOCYTE INFILTRATION AND THYROID AUTOANTIBODIES. TIMING AND DURATION-DEPENDENT EXPOSURE TO SPECIFIC ENDOCRINE DISRUPTING CHEMICALS (EDCS) HAS AN IMPACT ON THYROID DEVELOPMENT, FUNCTION, AND PROLIFERATION, LEADING TO THYROID DISEASE AND POTENTIALLY CANCER. THYROID HORMONE IMBALANCE, CHRONIC INFLAMMATION, AND EDCS ARE POTENTIAL RISK FACTORS FOR OXIDATIVE STRESS. OXYGEN FREE RADICALS ARE CAPABLE OF CAUSING DNA DAMAGE VIA STIMULATION OF THE MITOGEN-ACTIVATING PROTEIN KINASE OR PHOSPHATIDYLINOSITOL-3-KINASE AND/OR NUCLEAR FACTOR KB PATHWAYS, RESULTING IN TC-ASSOCIATED GENE MUTATIONS SUCH AS RET/PTC, AKAP9-BRAF, NTRK1, RAASF, PIK3CA, AND PTEN. STRESSFUL EVENTS DURING THE CRITICAL PERIODS OF PRENATAL AND EARLY LIFE CAN INFLUENCE NEUROENDOCRINE REGULATION AND INDUCE EPIGENETIC CHANGES. ABERRANT METHYLATION OF TUMOR SUPPRESSOR GENES SUCH AS P16INK4A, RASSF, AND PTEN IS ASSOCIATED WITH PTC; HISTONE H3 ACETYLATION IS SHOWN TO BE HIGHER IN TC, AND THYROID-SPECIFIC NONCODING RNAS ARE DOWNREGULATED IN PTC. THIS REVIEW FOCUSES ON THE ABOVE PROPOSED MECHANISMS THAT POTENTIALLY LEAD TO THYROID TUMORIGENESIS WITH THE AIM TO HELP IN THE DEVELOPMENT OF NOVEL PROGNOSTIC AND THERAPEUTIC STRATEGIES FOR TC. 2023 3 5564 11 ROLE OF HYPERMETHYLATION OF DAP-KINASE CPG ISLAND IN THE DEVELOPMENT OF THYROID LYMPHOMA. DEATH-ASSOCIATED PROTEIN-KINASE (DAP-KINASE) IS A SERINE/THREONINE KINASE WITH A DEATH DOMAIN THAT IS INVOLVED IN APOPTOSIS INDUCED BY INTERFERON-GAMMA, TNF-ALPHA, AND FAS LIGAND. EPIGENETIC DOWN-REGULATION OF DAP-KINASE GENE EXPRESSION BY HYPERMETHYLATION OF ITS PROMOTER REGION WAS REPORTED IN B-CELL MALIGNANCIES. PREVIOUS PATHOEPIDEMIOLOGIC STUDIES INDICATED THAT THYROID LYMPHOMA (TL) EVOLVES AMONG ACTIVE LYMPHOID CELLS IN CHRONIC LYMPHOCYTIC THYROIDITIS (CLTH). WITH USE OF METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION, THE METHYLATION STATUS OF DAP-KINASE CPG ISLAND WAS EXAMINED IN THYROID LESIONS OF 19 CASES WITH TL AND 9 WITH CLTH. THE FREQUENCY OF METHYLATION WAS HIGHER IN TL CASES (16 OF 19, 84.2%) THAN IN CLTH CASES (2 OF 9, 22.2%) (P < 0.01). DNA EXTRACTED FROM PERIPHERAL BLOOD LEUKOCYTES FROM TL AND CLTH CASES NEVER SHOWED METHYLATION, INDICATING THAT THE METHYLATION OCCURRED SOMATICALLY IN THE LESIONAL LYMPHOCYTES IN THYROID. THESE FINDINGS SUGGESTED THAT METHYLATION OF THE DAP-KINASE PROMOTER REGION MIGHT BE INVOLVED IN THE DEVELOPMENT OF TL FROM CLTH. 2000 4 3258 36 HEPATITIS C AND INTERFERON INDUCED THYROIDITIS. AUTOIMMUNE THYROID DISEASES (AITDS) ARE COMPLEX DISEASES THAT DEVELOP AS A RESULT OF INTERACTIONS BETWEEN GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS. SIGNIFICANT PROGRESS HAS BEEN MADE IN OUR UNDERSTANDING OF THE GENETIC AND ENVIRONMENTAL TRIGGERS CONTRIBUTING TO AITD. THE MAJOR ENVIRONMENTAL TRIGGERS OF AITD INCLUDE IODINE, SMOKING, MEDICATIONS, PREGNANCY, AND POSSIBLY STRESS. IN THIS REVIEW WE WILL FOCUS ON TWO WELL-DOCUMENTED ENVIRONMENTAL TRIGGERS OF AITD, HEPATITIS C VIRUS (HCV) INFECTION AND INTERFERON ALPHA (IFNA) THERAPY. CHRONIC HCV INFECTION HAS BEEN SHOWN TO BE ASSOCIATED WITH INCREASED INCIDENCE OF CLINICAL AND SUBCLINICAL AUTOIMMUNE THYROIDITIS (I.E. THE PRESENCE OF THYROID ANTIBODIES IN EUTHYROID SUBJECTS). MOREOVER, IFNA THERAPY OF CHRONIC HCV INFECTION IS ASSOCIATED WITH SUBCLINICAL OR CLINICAL THYROIDITIS IN UP TO 40% OF CASES WHICH CAN BE AUTOIMMUNE, OR NON-AUTOIMMUNE THYROIDITIS. IN SOME CASES INTERFERON INDUCED THYROIDITIS (IIT) IN CHRONIC HCV PATIENTS MAY RESULT IN SEVERE SYMPTOMATOLOGY NECESSITATING DISCONTINUATION OF THERAPY. WHILE THE EPIDEMIOLOGY AND CLINICAL PRESENTATION OF HCV AND INTERFERON INDUCED THYROIDITIS HAVE BEEN WELL CHARACTERIZED, THE MECHANISMS CAUSING THESE CONDITIONS ARE STILL POORLY UNDERSTOOD. 2010 5 4963 21 PATHOGENESIS OF THYROID NODULES: HISTOLOGICAL CLASSIFICATION? THYROID NODULE GENESIS MAY BE CONSIDERED AS AN AMPLIFICATION OF THYROID HETEROGENEITY DUE TO GENETIC AND/OR EPIGENETIC MECHANISMS. WE CLASSIFIED THE THYROID NODULES IN FIVE TYPES WITH DISTINCT HISTOLOGICAL FEATURES: HYPERPLASTIC, NEOPLASTIC, COLLOID, CYSTIC AND THYROIDITIC NODULES. HYPERPLASTIC: THYROCYTE PROLIFERATION IS UNDER THE CONTROL OF TSH BUT SEVERAL OTHER PARACRINE AND AUTOCRINE FACTORS ARE SECRETED BY FOLLICULAR CELLS, THE STROMAL APPARATUS AND THE LYMPHOCYTES, WHICH ARE IMPLICATED IN INITIATION AND PERPETUATION OF THYROID HYPERPLASIA. GROWTH OCCURS MAINLY THROUGH TSHR, CAMP AND PKA. CONSTITUTIVE CAMP OVERPRODUCTION HAS BEEN SHOWN TO BE DUE TO POINT MUTATION OF THE TSHR OR GS PROTEIN, PRODUCING OVERGROWTH AND HYPERFUNCTION. NEOPLASTIC: SEVERAL ACTIVATED ONCOGENES HAVE BEEN IDENTIFIED IN THYROID MALIGNANCIES. ONCOGENES RELEVANT TO THE THYROID CARCINOGENESIS ARE: MUTATED TSHR AND GSP (CONSTITUTIVE ACTIVATION OF CAMP); TRK (RECEPTOR FOR NGF); RET/PTC (PHOSPHORYLATION OF TYROSINE KINASE RECEPTOR)--AN ISOFORM OF THIS ONCOGENE IS INDUCED BY RADIATION: RAS (IT ENCODES GS PROTEINS TRANSDUCING MITOGENIC SIGNALS); AND C-MET (RECEPTOR FOR HEPATOCYTE GROWTH FACTOR). THE EVOLUTION OF A DIFFERENTIATED THYROID CANCER TOWARDS AN UNDIFFERENTIATED CANCER IS DUE TO A MUTATION OF A FAMILY OF PROTEINS (I.E., P53), WHICH ACTS AS A BRAKE, PREVENTING THE GENOMIC INSTABILITY OF CANCER. IT IS SUGGESTED THAT A TUMOR INITIATES BY RET OR RAS AND POSSIBLY PROGRESSES--AS A RESULT OF ADDITIONAL MUTATIONS AND BY P53 MUTATION--TO ANAPLASTIC CARCINOMA. COLLOID: FLATTENING OF THE EPITHELIUM AND DILATATION OF FOLLICLES CONTAINING VISCOUS MATERIAL--MADE UP BY A CONCENTRATED SOLUTION OF THYROGLOBULIN (HTG)--IS THE CHARACTERISTIC OF THE COLLOID NODULE. A DEFECT OF INTRALUMINAL REABSORPTION OF HTG HAS BEEN SUGGESTED BUT NOT PROVEN. EXPERIMENTALLY, A LOAD OF IODINE IS ABLE TO CHANGE THYROID HYPERPLASIA TO A COLLOID FEATURE; HOWEVER, A LOAD OF IODINE IS RARELY FOUND IN THE CLINICAL HISTORY OF PATIENTS. A NEW CLUE TO THE PATHOGENESIS COMES FROM THE FINDING THAT A RELEVANT PART OF THE COLLOID (10-20%) IS MADE UP OF INSOLUBLE GLOBULES, WHERE HTG IS COMPACTED IN A POLYMERIC FORM. IT IS SUGGESTED THAT STOCKING HTG INTO GLOBULES IS DEFECTIVE IN COLLOID NODULES, LEADING TO ENORMOUS ENLARGEMENT OF THE FOLLICLE. CYSTIC: IT IS ESTIMATED THAT BETWEEN 15 AND 40% OF THYROID NODULES ARE PARTLY OR ENTIRELY CYSTIC. THE 'TRUE CYST' IS RARE; MOST OF THE SO-CALLED CYSTIC NODULES ARE 'PSEUDOCYSTS', WHICH FOLLOW NECROSIS AND COLLIQUATION. NECROSIS ISSUES AS AN IMBALANCE BETWEEN GROWTH AND THE PRECISELY REGULATED PROCESS OF ANGIOGENESIS. MORE RECENTLY, THE VEGF/VPF HAS BEEN FOUND TO BE AT THE ORIGIN OF RECENT AND RECURRENT CYSTS. IMMUNOTOXIC AND APOPTOTIC MECHANISMS HAVE ALSO BEEN SUGGESTED. CHEMICAL ANALYSIS OF CYSTIC FLUID SHOWED A 'DENATURED' AND 'SERUM-LIKE' PATTERN SUGGESTING DIFFERENT MECHANISMS IN THE PATHOGENESIS OF THE PSEUDOCYSTIC THYROID NODULES. THYROIDITIC: NODULAR LYMPHOCYTIC THYROIDITIS (NLT) INCLUDES TWO DIFFERENT ENTITIES: 1) LYMPHOCYTE THYROIDITIS GROWING AS A NODULE IN A HYPERPLASTIC OR NORMAL GLAND, AND 2) LYMPHOCYTE THYROIDITIS ASSOCIATED IN THE SAME NODULE WITH OTHER NODULAR DISEASES OF THE THYROID: PAPILLARY THYROID CARCINOMA AND LYMPHOMA HAVE BEEN FOUND TO BE ASSOCIATED TO CHRONIC LYMPHOCYTIC THYROIDITIS. 2001 6 6831 11 [HYPERMETHYLATION OF DAP-KINASE GENE CPG ISLAND IN MALIGNANT LYMPHOMA WITH B-CELL PHENOTYPE]. DEATH-ASSOCIATED PROTEIN-KINASE(DAP-KINASE) IS A PRO-APOPTOTIC SERINE/THREONINE KINASE WITH A DEATH DOMAIN, WHICH IS INVOLVED IN APOPTOSIS INDUCED BY INTERFERON-GAMMA, TUMOR NECROSIS FACTOR-ALPHA, AND FAS LIGAND. EPIGENETIC DOWN-REGULATION OF DAP-KINASE GENE EXPRESSION BY HYPERMETHYLATION OF ITS PROMOTER REGION WAS REPORTED IN CERTAIN KINDS OF MALIGNANCIES. PREVIOUS PATHO-EPIDEMIOLOGICAL STUDIES INDICATED THAT THYROID LYMPHOMA(TL) EVOLVES AMONG ACTIVE LYMPHOID CELLS IN CHRONIC LYMPHOCYTIC THYROIDITIS(CLTH). WITH THE USE OF METHYLATION SPECIFIC POLYMERASE CHAIN REACTION, METHYLATION STATUS OF DAP-KINASE CPG ISLAND WAS EXAMINED IN THYROID LESIONS OF 19 CASES WITH TL AND 9 WITH CLTH. FREQUENCY OF METHYLATION WAS HIGHER IN TL CASES(16 OF 19, 84.2%) THAN IN CLTH CASES(2 OF 9, 22.2%) (P < 0.01). DNA EXTRACTED FROM PERIPHERAL BLOOD LEUKOCYTES FROM TL AND CLTH CASES NEVER SHOWED METHYLATION, INDICATING THAT THE METHYLATION OCCURRED SOMATICALLY IN LESIONAL LYMPHOCYTES IN THE THYROID. WE ALSO EXAMINED THE METHYLATION STATUS OF DAP-KINASE GENE IN 16 CASES OF T-CELL MALIGNANCIES INCLUDING EIGHT ADULT T-CELL LEUKEMIA/LYMPHOMA AND 24 NK/T-CELL, 34 B-CELL, AND TWO IMMUNOPHENOTYPICALLY UNDETERMINED LYMPHOMAS. FREQUENCY OF METHYLATION WAS HIGHER IN B-CELL(27 OF 34, 79.4%) THAN IN T-CELL MALIGNANCIES(EIGHT OF 16, 50%) (P < 0.05). FIFTEEN OF 24(62.5%) NK/T-CELL LYMPHOMAS SHOWED DNA METHYLATION. HEMATOPOIETIC CELL LINES WITH A METHYLATED GENE WERE RESISTANT TO APOPTOSIS. TREATMENT OF THE CELLS WITH A DEMETHYLATING AGENT RESTORED APOPTOTIC CELL DEATH IN ONE B-CELL LYMPHOMA CELL LINE WITH DNA METHYLATION. OUR RESULTS SUGGESTED THAT SUPPRESSION OF DAP-KINASE EXPRESSION BY DNA METHYLATION MIGHT PLAY A ROLE IN THE DEVELOPMENT OF B-CELL MALIGNANCIES. 2001 7 6727 20 VITILIGO AND CHRONIC AUTOIMMUNE THYROIDITIS. VITILIGO, THE DISCOLORATION OF THE SKIN, HAS DIFFERENT AUTOIMMUNE MECHANISMS REFLECTED BY MANY BIOMARKERS AS SHOWN BY SKIN HISTOLOGY, STAINING FOR CD4 AND CD8 T LYMPHOCYTES, CHEMOKINE LIGAND 9 OR CIRCULATING CYTOKINES SUCH AS INTERLEUKIN (IL)-1 BETA, INTERFERON (IFN)-GAMMA, TRANSFORMING GROWTH FACTOR (TGF)-BETA, ANTIBODIES, MARKERS OF OXIDATIVE STRESS, CHEMOKINES, AND OTHERS. IN THIS NARRATIVE REVIEW, WE AIM TO OVERVIEW VITILIGO IN RELATIONSHIP WITH CHRONIC AUTOIMMUNE THYROIDITIS. REGARDING VITILIGO, MORE THAN 50 DIFFERENT GENETIC LOCI HAVE BEEN ASSOCIATED WITH THIS DISEASE, AND THE HERITABILITY IS HIGH. THERE IS A 20% RISK OF AN ENVIRONMENTAL CONNECTION WHICH MAY ALSO ACT AS A TRIGGER; MOREOVER, THE ASSOCIATION WITH HUMAN LEUKOCYTE ANTIGEN (HLA) EXPRESSION IS WELL RECOGNIZED. THE SPECIFIC LESIONS DISPLAY CD8+ TISSUE-RESIDENT MEMORY T CELLS AS CONTINUOUS KEY ACTIVATORS OF MELANOCYTES. THE ASSOCIATION WITH CHRONIC THYROIDITIS IS BASED ON COMMON AUTOIMMUNE BACKGROUND AND EXCESSIVE REACTIVE OXYGEN SPECIES THAT DESTROY MELANOCYTES AND THYROCYTES (OXIDATIVE STRESS HYPOTHESIS) WITH THYROXINE AND MELANIN AS TARGET MOLECULES, THUS SHARING A COMMON ORIGIN: TYROSINE. MOREOVER, COMMON EPIGENETIC ANOMALIES OR MUTATIONS OF THE FORKHEAD TRANSCRIPTION FACTOR D3 (FOXD3) HAVE BEEN DESCRIBED. SINCE VITILIGO AFFECTS UP TO 1-2% OF THE POPULATION WORLDWIDE AND 34% OF PATIENTS HAVE POSITIVE THYROID ANTIBODIES, APART FROM COMMON AUTOIMMUNITY BACKGROUND AND OXIDATIVE STRESS TOXICITY, THE ASSOCIATION IS CLINICALLY RELEVANT FOR DIFFERENT PRACTITIONERS. 2021 8 3694 16 INFLAMMATORY COMPONENTS OF THE THYROID CANCER MICROENVIRONMENT: AN AVENUE FOR IDENTIFICATION OF NOVEL BIOMARKERS. THE INCIDENCE OF THYROID CANCER IN THE UNITED STATES IS ON THE RISE WITH AN APPRECIABLY HIGH DISEASE RECURRENCE RATE OF 20-30%. ANAPLASTIC THYROID CANCER (ATC), ALTHOUGH RARE IN OCCURRENCE, IS AN AGGRESSIVE FORM OF CANCER WITH LIMITED TREATMENT OPTIONS AND BLEAK CURE RATES. THIS CHAPTER USES DISCUSSIONS OF IN VITRO MODELS THAT ARE REPRESENTATIVE OF PAPILLARY, ANAPLASTIC, AND FOLLICULAR THYROID CANCER TO EVALUATE THE CROSSTALK BETWEEN SPECIFIC CELLS OF THE TUMOR MICROENVIRONMENT (TME), WHICH SERVES AS A HIGHLY HETEROGENEOUS REALM OF SIGNALING CASCADES AND METABOLISM THAT ARE ASSOCIATED WITH TUMORIGENESIS. THE CELLULAR CONSTITUENTS OF THE TME CARRY OUT VARYING CHARACTERISTIC IMMUNOMODULATORY FUNCTIONS THAT ARE DISCUSSED THROUGHOUT THIS CHAPTER. THE AFOREMENTIONED CELL TYPES INCLUDE CANCER-ASSOCIATED FIBROBLASTS (CAFS), ENDOTHELIAL CELLS (ECS), AND CANCER STEM CELLS (CSCS), AS WELL AS SPECIFIC IMMUNE CELLS, INCLUDING NATURAL KILLER (NK) CELLS, DENDRITIC CELLS (DCS), MAST CELLS, T REGULATORY (TREG) CELLS, CD8+ T CELLS, AND TUMOR-ASSOCIATED MACROPHAGES (TAMS). TAM-MEDIATED INFLAMMATION IS ASSOCIATED WITH A POOR PROGNOSIS OF THYROID CANCER, AND THE MOLECULAR BASIS OF THE CELLULAR CROSSTALK BETWEEN MACROPHAGES AND THYROID CANCER CELLS WITH RESPECT TO INDUCING A METASTATIC PHENOTYPE IS NOT YET KNOWN. THE DYNAMIC NATURE OF THE PHYSIOLOGICAL TRANSITION TO PATHOLOGICAL METASTATIC PHENOTYPES WHEN ESTABLISHING THE TME ENCOMPASSES A WIDE RANGE OF CHARACTERISTICS THAT ARE FURTHER EXPLORED WITHIN THIS CHAPTER, INCLUDING THE ROLES OF SOMATIC MUTATIONS AND EPIGENETIC ALTERATIONS THAT DRIVE THE GENETIC HETEROGENEITY OF CANCER CELLS, ALLOWING FOR SELECTIVE ADVANTAGES THAT AID IN THEIR PROLIFERATION. INDUCTION OF THESE PROLIFERATING CELLS IS TYPICALLY ACCOMPLISHED THROUGH INFLAMMATORY INDUCTION, WHEREBY CHRONIC INFLAMMATION SETS UP A CONSTANT PHYSIOLOGICAL STATE OF INFLAMMATORY CELL RECRUITMENT. THE SECRETIONS OF THESE INFLAMMATORY CELLS CAN ALTER THE GENETIC MAKEUP OF PROLIFERATING CELLS, WHICH CAN IN TURN, PROMOTE TUMOR GROWTH.THIS CHAPTER ALSO PRESENTS AN IN-DEPTH ANALYSIS OF MOLECULAR INTERACTIONS WITHIN THE TME, INCLUDING SECRETORY CYTOKINES AND EXOSOMES. SINCE THE EXOSOMAL CARGO OF A CELL IS A REFLECTION AND FINGERPRINT OF THE ORIGINATING PARENTAL CELLS, THE PROFILING OF EXOSOMAL MIRNA DERIVED FROM THYROID CANCER CELLS AND MACROPHAGES IN THE TME MAY SERVE AS AN IMPORTANT STEP IN BIOMARKER DISCOVERY. IDENTIFICATION OF A DISTINCT SET OF TUMOR SUPPRESSIVE MIRNAS DOWNREGULATED IN ATC-SECRETED EXOSOMES INDICATES THEIR ROLE IN THE REGULATION OF TUMOR SUPPRESSIVE GENES THAT MAY INCREASE THE METASTATIC PROPENSITY OF ATC. ADDITIONALLY, THE HIGH EXPRESSION OF PRO-INFLAMMATORY CYTOKINES IN STUDIES LOOKING AT THYROID CANCER AND ACTIVATED MACROPHAGE CONDITIONED MEDIA SUGGESTS THE EXISTENCE OF AN INFLAMMATORY TME IN THYROID CANCER. NEW FINDINGS ARE SUGGESTIVE OF THE PRESENCE OF A METASTATIC NICHE IN ATC TISSUES THAT IS INFLUENCED BY THYROID TUMOR MICROENVIRONMENT SECRETOME-INDUCED EPITHELIAL TO MESENCHYMAL TRANSITION (EMT), MEDIATED BY A RECIPROCAL INTERACTION BETWEEN THE PRO-INFLAMMATORY M1 MACROPHAGES AND THE THYROID CANCER CELLS. THUS, TARGETING THE METASTATIC THYROID CARCINOMA MICROENVIRONMENT COULD OFFER POTENTIAL THERAPEUTIC BENEFITS AND SHOULD BE EXPLORED FURTHER IN PRECLINICAL AND TRANSLATIONAL MODELS OF HUMAN METASTATIC THYROID CANCER. 2021 9 5384 14 REDIFFERENTIATION OF RADIOIODINE-REFRACTORY THYROID CANCERS. THE MANAGEMENT OF RADIOIODINE REFRACTORY THYROID CANCERS (RAIR TC) IS CHALLENGING FOR THE CLINICIAN. TYROSINE KINASE INHIBITORS CLASSICALLY PRESCRIBED IN THIS SETTING CAN FAIL DUE TO PRIMARY OR ACQUIRED RESISTANCE OR THE NECESSITY OF DRUG WITHDRAWAL BECAUSE OF SERIOUS OR MODERATE BUT CHRONIC AND DELETERIOUS ADVERSE EFFECTS. THUS, THE CONCEPT OF REDIFFERENTIATION STRATEGY, WHICH INVOLVES TREATING PATIENTS WITH ONE OR MORE DRUGS CAPABLE OF RESTORING RADIOIODINE SENSITIVITY FOR RAIR TC, HAS EMERGED. THE AREA OF REDIFFERENTIATION STRATEGY LEADS TO THE CREATION OF NEW DEFINITIONS OF RAIR TC INCLUDING PERSISTENT NON RADIOIODINE-AVID PATIENTS AND 'TRUE' RAIR TC PATIENTS. THE LATTER GROUP PRESENTS A RESTORED OR INCREASED RADIOIODINE UPTAKE IN METASTATIC LESIONS BUT WITH NO RADIOLOGICAL RESPONSE ON CONVENTIONAL IMAGING, THAT IS, PROGRESSION OF A METASTATIC DISEASE, THUS PROVING THAT THEY ARE 'TRULY' RESISTANT TO THE RADIATION DELIVERED BY RADIOIODINE. UNLIKE THESE PATIENTS, METASTATIC TC PATIENTS WITH RESTORED RADIOIODINE UPTAKE OFFER THE HOPE OF PROLONGED REMISSION OR EVEN CURE OF THE DISEASE AS FOR RADIOIODINE-AVID METASTATIC TC. HERE, WE REVIEW THE DIFFERENT REDIFFERENTIATION STRATEGIES BASED ON THE UNDERLYING MOLECULAR MECHANISM LEADING TO THE SODIUM IODIDE SYMPORTER (NIS) AND RADIOIODINE UPTAKE REINDUCTION, THAT IS, BY MODULATING SIGNALING PATHWAYS, NIS TRANSCRIPTION, NIS TRAFFICKING TO THE PLASMA MEMBRANE, NIS POST-TRANSCRIPTIONAL REGULATION, BY GENE THERAPY AND OTHER POTENTIAL STRATEGIES. WE DISCUSS CLINICAL TRIALS AND PROMISING PRECLINICAL DATA OF POTENTIAL FUTURE TARGETS. 2020 10 30 21 A BRIEF LOOK AT HASHIMOTO'S DISEASE, ADRENAL INCIDENTALOMAS, OBESITY AND INSULIN RESISTANCE-COULD ENDOCRINE DISRUPTORS BE THE OTHER SIDE OF THE SAME COIN? HASHIMOTO'S DISEASE (HD) IS THE MOST COMMON CAUSE OF HYPOTHYROIDISM IN DEVELOPED COUNTRIES. THE EXACT PATHOMECHANISM BEHIND IT HAS NOT BEEN CLEARLY ESTABLISHED; HOWEVER, AN INTERPLAY OF GENETIC SUSCEPTIBILITY, ENVIRONMENTAL TRIGGERS (INCLUDING DIET) AND EPIGENETIC FACTORS SEEMS TO BE INVOLVED. AMONG THE LATTER, INCREASINGLY MORE ATTENTION HAS BEEN PAID TO SOME HORMONALLY ACTIVE SUBSTANCES, KNOWN AS ENDOCRINE DISRUPTORS, WHICH ARE COMMONLY USED WORLDWIDE. HD HAS BECOME A CONDITION WIDELY REPORTED IN THE MEDIA, ACTING AS A CULPRIT FOR INEXPLICABLE WEIGHT GAIN, CHRONIC FATIGUE OR WEAKNESS. NEVERTHELESS, THE RECOGNITION OF HD IS UNDENIABLY INCREASING AND REPRESENTS A MAJOR PUBLIC HEALTH BURDEN. AT THE SAME TIME, IMPROVING ACCESS TO IMAGING TESTS HAS INCREASED THE NUMBER OF INCIDENTALLY DIAGNOSED ADRENAL TUMORS. ABOVE ALL, THE WIDESPREAD USE OF CHEST COMPUTED TOMOGRAPHY (CT) DUE TO THE COVID-19 PANDEMIC HAS CONTRIBUTED TO FREQUENT INCIDENTAL DETECTION OF ADRENAL LESIONS. FORTUNATELY, A VAST MAJORITY OF THESE FINDINGS ARE ASYMPTOMATIC BENIGN TUMORS WITH NO EXCESSIVE HORMONAL ACTIVITY, AND THEREFORE, THEY ARE DEFINED AS ADRENAL INCIDENTALOMAS (AIS). INTERESTINGLY, RECENT STUDIES HAVE INDICATED THAT PATIENTS WITH AIS ARE MORE PRONE TO OBESITY AND INSULIN RESISTANCE. ALTHOUGH MUTUAL RELATIONSHIPS BETWEEN THE THYROID AND THE ADRENAL GLANDS HAVE BEEN STUDIED WIDELY, STILL, LITTLE IS KNOWN ABOUT THE POSSIBLE PATHOPHYSIOLOGICAL ASSOCIATIONS BETWEEN THYROID AUTOIMMUNITY AND THE OCCURRENCE OF ADRENAL INCIDENTALOMAS. THIS ARTICLE PRESENTS A BRIEF REVIEW OF THE COMMON ENDOCRINE DISORDERS WITH A SPECIAL FOCUS ON THE FREQUENTLY COEXISTING INSULIN RESISTANCE AND/OR OBESITY. FURTHERMORE, IN RESPONSE TO THE RECENT GROWING INTEREST IN ENDOCRINE DISRUPTORS, WITH THEIR TRANSGENERATIONAL EPIGENETIC EFFECTS THAT INFLUENCE HORMONAL SYSTEM FUNCTION, A CONCISE OVERVIEW OF THE TOPIC HAS ALSO BEEN INCLUDED. 2023 11 1106 14 COMBINED TOXICITY OF ENDOCRINE-DISRUPTING CHEMICALS: A REVIEW. THE COMBINED TOXICOLOGICAL ASSESSMENT PROVIDES A REALISTIC APPROACH FOR HAZARD EVALUATION OF CHEMICAL COCKTAILS THAT CO-EXISTED IN THE ENVIRONMENT. THIS REVIEW PROVIDES A HOLISTIC INSIGHT INTO THE STUDIES HIGHLIGHTING THE MIXTURE TOXICITY OF THE ENDOCRINE-DISRUPTING CHEMICALS (EDCS), ESPECIALLY FOCUSING ON THE SCREENING OF BIOCHEMICAL PATHWAYS AND OTHER TOXICOGENETIC ENDPOINTS. REVIEWED LITERATURE SHOWED THAT NUMEROUS MULTIPLEXED TOXICOGENOMIC TECHNIQUES WERE APPLIED TO DETERMINE REPRODUCTIVE EFFECTS IN VERTEBRATES, BUT LIMITED STUDIES WERE FOUND IN NON-MAMMALIAN SPECIES AFTER MIXTURE CHEMICAL EXPOSURE. FURTHER, WE FOUND THAT THE EXPERIMENTAL DESIGN AND CONCENTRATION SELECTION ARE THE TWO IMPORTANT PARAMETERS IN MIXTURE TOXICITY STUDIES THAT SHOULD BE TIME- AND COST-EFFECTIVE, HIGHLY PRECISE, AND ENVIRONMENTALLY RELEVANT. A SUMMARY OF EDC MIXTURES AFFECTING THE THYROID AXIS, ESTROGEN AXIS, ANDROGEN AXIS, GROWTH STRESS, AND IMMUNE SYSTEM VIA IN VIVO BIOASSAYS WAS ALSO PRESENTED. IT IS INTERESTING TO MENTION THAT MAJORITY OF ESTROGENIC EFFECTS OF THE MIXTURES WERE SEX-DEPENDENT, PARTICULARLY OBSERVED IN MALE FISH AS COMPARED TO FEMALE FISH. FURTHER, THE ANDROGEN AXIS WAS PERTURBED WITH SERIOUS MALFORMATIONS IN MALE RAT TESTIS (EPIDIDYMAL OR GUBERNACULAR LESIONS, AND DECIDUOUS SPERMATIDS). ALSO, TRANSGENERATIONAL EPIGENETIC EFFECTS WERE PROMOTED IN THE F(3) AND F(4) GENERATIONS IN THE FORM OF DNA METHYLATION EPIMUTATIONS IN SPERM, INCREASING POLYCYSTIC OVARIES AND REDUCING THE OFFSPRING. SIMILARLY, INCREASED OXIDATIVE STRESS, HIGH ANTIOXIDANT ENZYMATIC ACTIVITIES, DISTURBED ESTROUS CYCLE, AND DECREASED STEROIDOGENESIS WERE THE COMMONLY FOUND EFFECTS AFTER ACUTE OR CHRONIC EXPOSURE TO EDC MIXTURES. IMPORTANTLY, THE CONCENTRATION ADDITION (CA) AND INDEPENDENT ACTION (IA) MODELS BECAME MORE PREVALENT AND SUITABLE PREDICTIVE MODELS TO UNVEIL THE PROMINENCE OF SYNERGISTIC ESTROGENIC AND ANTI-ANDROGENIC EFFECTS OF CHEMICAL MIXTURES. MORE IMPORTANTLY, THIS REVIEW ENCOMPASSES THE RESEARCH CHALLENGES AND GAPS IN THE EXISTING KNOWLEDGE AND SPECIFIC FUTURE RESEARCH PERSPECTIVES ON COMBINED TOXICITY. 2021 12 2840 15 FRAMEWORK ANALYSIS FOR THE CARCINOGENIC MODE OF ACTION OF NITROBENZENE. NITROBENZENE (CASRN: 98-95-3) HAS BEEN SHOWN TO INDUCE CANCERS IN MANY TISSUES INCLUDING KIDNEY, LIVER, AND THYROID, FOLLOWING CHRONIC INHALATION IN ANIMALS. HOWEVER, WITH A FEW EXCEPTIONS, GENOTOXICITY ASSAYS USING NITROBENZENE HAVE GIVEN NEGATIVE RESULTS. SOME DNA BINDING/ADDUCT STUDIES HAVE BROUGHT FORTH QUESTIONABLE RESULTS AND, CONSIDERING THE AVAILABLE WEIGHT OF EVIDENCE, IT DOES NOT APPEAR THAT NITROBENZENE CAUSES CANCER VIA A GENOTOXIC MODE OF ACTION. NITROBENZENE PRODUCES A NUMBER OF FREE RADICALS DURING ITS REDUCTIVE METABOLISM, IN THE GUT AS WELL AS AT THE CELLULAR LEVEL, AND GENERATES SUPEROXIDE ANION AS A BY-PRODUCT DURING OXIDATIVE MELABOLISM. THE REACTIVE SPECIES GENERATED DURING NITROBENZENE METABOLISM ARE CONSIDERED CANDIDATES FOR CARCINOGENICITY. FURTHERMORE, SEVERAL LINES OF EVIDENCE SUGGEST THAT NITROBENZENE EXERTS ITS CARCINOGENICITY THROUGH A NON-DNA REACTIVE (EPIGENETIC) FASHION, SUCH AS A STRONG TEMPORAL RELATIONSHIP BETWEEN NON-, PRE-, AND NEOPLASTIC LESIONS LEADING TO CARCINOGENESIS. IN THIS REPORT, WE FIRST DESCRIBE THE ABSORPTION, DISTRIBUTION, METABOLISM, AND EXCRETION OF NITROBENZENE FOLLOWED BY A SUMMARY OF THE AVAILABLE GENOTOXICITY STUDIES AND THE ONLY AVAILABLE CANCER BIOASSAY. WE SUBSEQUENTLY REFER TO THE MODE OF ACTION FRAMEWORK OF THE U.S. ENVIRONMENTAL PROTECTION AGENCY'S 2005 GUIDELINES FOR CARCINOGEN RISK ASSESSMENT AS A BASIS FOR PRESENTING POSSIBLE MODES OF ACTION FOR NITROBENZENE-INDUCED CANCERS OF THE LIVER, THYROID, AND KIDNEY, AS SUPPORTED BY THE AVAILABLE EXPERIMENTAL DATA. THE RATIONALE(S) REGARDING HUMAN RELEVANCE OF EACH MODE OF ACTION IS ALSO PRESENTED. FINALLY, WE HYPOTHESIZE THAT THE CARCINOGENIC MODE OF ACTION FOR NITROBENZENE IS MULTIFACTORIAL IN NATURE AND REFLECTIVE OF FREE RADICALS, INFLAMMATION, AND/OR ALTERED METHYLATION. 2007 13 1148 21 CONGENITAL HYPOTHYROIDISM AND THYROID CANCER. DIFFERENTIATED THYROID CARCINOMA (DTC) COMBINED WITH CONGENITAL HYPOTHYROIDISM (CH) IS A RARE SITUATION, AND THERE IS NO WELL-ESTABLISHED CAUSAL RELATIONSHIP. CH IS A COMMON CONGENITAL ENDOCRINE, WHILE DTC OCCURRING IN CHILDHOOD REPRESENTS 0.4-3% OF ALL MALIGNANCIES AT THIS STAGE OF LIFE. THE ASSOCIATION OF CH WITH DTC COULD BE RELATED TO DYSHORMONOGENETIC GOITER (DHG) OR DEVELOPMENTAL ABNORMALITIES. THIS REVIEW WILL EXPLORE THE CLINICAL FEATURES AND THE MOLECULAR MECHANISMS POTENTIALLY ASSOCIATED WITH THE APPEARANCE OF DTC IN CH: SPORADIC SOMATIC DRIVER MUTATIONS, CHRONIC INCREASE OF THYROID-STIMULATING HORMONE (TSH) LEVELS, HIGHER CONCENTRATIONS OF HYDROGEN PEROXIDE (H2O2), CELL DIVISION CYCLE ASSOCIATED 8 (BORELAIN/CDC8) GENE MUTATIONS, AND IN OTHERS GENES ASSOCIATED WITH CH - EITHER ALONE OR ASSOCIATED WITH THE MECHANISMS INVOLVED IN DYSHORMONOGENESIS. THERE ARE SOME PITFALLS IN THE DIAGNOSIS OF THYROID CANCER IN PATIENTS WITH CH WITH NODULAR GOITER, AS THE PROPER CYTOLOGICAL DIAGNOSIS OF NODULES OF PATIENTS WITH DYSHORMONOGENESIS MIGHT BE DEMANDING DUE TO THE SPECIFIC ARCHITECTURAL AND CYTOLOGICAL APPEARANCE, WHICH MAY LEAD TO AN ERRONEOUS INTERPRETATION OF MALIGNANCY. THE PURPOSE OF THIS ARTICLE IS TO SUGGEST AN ANALYTICAL FRAMEWORK THAT EMBRACES THE FUNDAMENTAL RELATIONSHIPS BETWEEN THE VARIOUS ASPECTS OF CH AND CDT. IN FACE OF THIS SCENARIO, THE ENTIRE GENETIC AND EPIGENETIC CONTEXT, THE COMPLEX FUNCTIONING, AND CROSS TALK OF CELL SIGNALING MAY DETERMINE CELLULAR MECHANISMS PROMOTING BOTH THE MAINTENANCE OF THE DIFFERENTIATED STATE OF THE THYROID FOLLICULAR CELL AND THE DISRUPTION OF ITS HOMEOSTASIS LEADING TO CANCER. WHEREAS, THE EXACT MECHANISMS FOR THYROID CANCER DEVELOPMENT IN CH REMAIN TO BE ELUCIDATED. 2021 14 5450 15 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 15 3934 17 LIVER TUMOR INDUCTION. THE SIGNIFICANCE OF THE DEVELOPMENT OF NODULAR LIVER LESIONS IN RODENTS FOLLOWING THE ADMINISTRATION OF TEST AGENTS RAISES SEVERAL QUESTIONS WHICH COULD BE PLACED IN ONE OF TWO GENERAL CATEGORIES: DIAGNOSTIC AND INTERPRETATIONAL. FROM A DIAGNOSTIC POINT OF VIEW, THE PROPER CLASSIFICATION OF LIVER TUMORS INTO A BENIGN AND MALIGNANT CATEGORY HAS TO BE BASED ON THE DIRECT CORRELATION BETWEEN THE MORPHOLOGY AND THE BIOLOGIC BEHAVIOR OF THE LESIONS. THEREFORE, EXTREME CARE SHOULD BE TAKEN TO SEPARATE THE MALIGNANT TUMORS FROM THE BENIGN AND THE BENIGN NEOPLASIA FROM THE HYPERPLASIA. THE SUBSTITUTION OF THE TERM "NEOPLASTIC NODULE" FOR HYPERPLASTIC NODULE IN RATS IS MISLEADING. MOST OF THESE NODULES, WHEN INDUCED UNDER SPECIAL EXPERIMENTAL CONDITIONS, MAY REGRESS OR REMODEL AND THUS THEY ARE NOT NEOPLASTIC IN NATURE. CHRONIC CARCINOGENICITY BIOASSAYS SHOULD INCLUDE "STOP" TYPE OF TREATMENT LEAVING ENOUGH OF THE OBSERVATIONAL TIME TO ESTABLISH THE FATE OF INDUCED NODULAR LESIONS. THE INDUCTION OF HISTOCHEMICALLY CHANGED FOCI CAN SERVE ONLY AS AN INDICATION OF POTENTIAL HEPATOCARCINOGENICITY AND SHOULD NOT BE EQUATED WITH THE INDUCTION OF BONA FIDE CANCER. THE BIOLOGIC INTERPRETATION OF NODULAR LIVER LESIONS, ESPECIALLY IN MICE, NEEDS FURTHER SCRUTINY BECAUSE THESE LESIONS HAVE A TENDENCY TO DEVELOP SPONTANEOUSLY WITH HIGH INCIDENCE IN SOME STRAINS. THIS CHARACTERISTIC THEN RAISES THE QUESTION AS TO THE MECHANISM BY WHICH VARIOUS AGENTS AUGMENT AND/OR ACCELERATE THE DEVELOPMENT OF SUCH TUMORS. IS THIS ACTION PRIMARILY PROMOTING OR INITIATING IN NATURE OR DOES IT REPRESENT THE INDUCTION OF TUMORS DE NOVO? THE ANSWER TO THIS DILEMMA MAY HAVE A DECISIVE BEARING ON CARCINOGENIC RISK ASSESSMENT AND THE TYPE OF REGULATORY ACTION, SINCE THE PROMOTING AGENTS POSSESS A THRESHOLD EFFECT AND THE PROMOTED CHANGES MAY REGRESS FOLLOWING WITHDRAWAL OF TREATMENT. THE INTERPRETATION OF HEPATOCARCINOGENESIS IS FURTHER COMPLICATED BY THE FACT THAT SEVERAL FACTORS, SUCH AS SEX HORMONAL ENVIRONMENT, INCREASED MITOTIC ACTIVITY FOLLOWING AN EXCESSIVE LOSS OF PARENCHYMAL CELLS, DEGREE OF CALORIC INTAKE, ENZYMATIC COMPLEMENT, AND ANIMALS' AGE AT THE TIME OF THE EXPOSURE TO A TEST AGENT, MAY INFLUENCE THE OUTCOME OF LIVER TUMOR DEVELOPMENT BY MODULATING "INITIATION" AND/OR "PROMOTION" OF CARCINOGENESIS. BROAD FLUCTUATION IN THE HISTORIC INCIDENCE OF LIVER TUMORS FURTHER COMPOUNDS THE COMPLEXITY OF THE PROPER BIOASSAY INTERPRETATION. THE SPECIFICALLY DESIGNED EXPERIMENTS MAY HAVE THE OBJECTIVE TO EXPLORE PREDOMINANTLY THE INITIATING OR PROMOTING EFFECTS OF THE AGENT. SUCH PROTOCOLS SHOULD BE USED WHENEVER NECESSARY TO DIFFERENTIATE BETWEEN THESE TWO MECHANISMS OF ACTION. IN THE CAUCASIANS, THE "SPONTANEOUS" DEVELOPMENT OF THE PRIMARY HEPATOCELLULAR TUMORS IS RARE. THE MAJORITY OF THESE TUMORS ARE MALIGNANT AND RAPIDLY FATAL. ACCORDING TO SOME HUMAN PATHOLOGISTS, THE BENIGN VARIETY OF LIVER TUMORS IS RARE AND IT DOES NOT REPRESENT NECESSARILY A PREMALIGNANT STAGE IN TUMOR DEVELOPMENT. CARCINOMA OF THE LIVER MAY OCCUR IN INFANCY, ESPECIALLY IN MALES BEFORE THE AGE OF 2 YEARS. THIS SUGGESTS A GENETIC CAUSATION OR CARCINOGENIC EXPOSURE IN UTERO. ONE OF THE GEOGRAPHIC FACTORS WHICH SIGNIFICANTLY ENHANCES THE INCIDENCE OF HEPATOCELLULAR CARCINOMA IN HUMANS IS EXPOSURE TO AFLATOXIN B(1) WHICH IS APPARENTLY POTENTIATED BY CONCURRENT LIVER CIRRHOSIS. BECAUSE MANY MORE AGENTS HAVE BEEN FOUND TO BE HEPATOCARCINOGENIC IN MICE AND RATS THAN IN MEN, A QUESTION ARISES AS TO THE DIRECT RELEVANCE OF RODENT STUDIES TO HUMANS. A BALANCED ASSESSMENT OF THE CARCINOGENICITY OF THE AGENT COULD ONLY BE REACHED IN CONSIDERING BOTH THE PHARMACOKINETICS AND THE DEVELOPMENT OF MALIGNANT NEOPLASIA IN OTHER ORGANS. IN THE CASE OF POSITIVE CARCINOGENICITY ASSESSMENT, THE OUTCOME OF THE MUTAGENICITY BIOASSAYS CAN SUGGEST GENIC (GENOTOXIC) OR PARAGENIC (EPIGENETIC) MODE OF ACTION IN MAMMALIAN SYSTEMS. 1982 16 5843 12 STUDIES ON THE CARCINOGENICITY OF POTASSIUM IODIDE IN F344 RATS. A CHRONIC TOXICITY AND CARCINOGENICITY STUDY, IN WHICH MALE AND FEMALE F344/DUCRJ RATS WERE GIVEN POTASSIUM IODIDE (KI) IN THE DRINKING WATER AT CONCENTRATIONS OF 0, 10, 100 OR 1000 PPM FOR 104 WEEKS, AND A TWO-STAGE CARCINOGENICITY STUDY OF APPLICATION AT 0 OR 1000 PPM FOR 83 WEEKS FOLLOWING A SINGLE INJECTION OF N-BIS(2-HYDROXYPROPYL)NITROSAMINE (DHPN), WERE CONDUCTED. IN THE FORMER, SQUAMOUS CELL CARCINOMAS WERE INDUCED IN THE SALIVARY GLANDS OF THE 1000 PPM GROUP, BUT NO TUMORS WERE OBSERVED IN THE THYROID. IN THE TWO-STAGE CARCINOGENICITY STUDY, THYROIDAL WEIGHTS AND THE INCIDENCE OF THYROID TUMORS DERIVED FROM THE FOLLICULAR EPITHELIUM WERE SIGNIFICANTLY INCREASED IN THE DHPN+KI AS COMPARED WITH THE DHPN ALONE GROUP. THE RESULTS OF OUR STUDIES SUGGEST THAT EXCESS KI HAS A THYROID TUMOR-PROMOTING EFFECT, BUT KI PER SE DOES NOT INDUCE THYROID TUMORS IN RATS. IN THE SALIVARY GLAND, KI WAS SUGGESTED TO HAVE CARCINOGENIC POTENTIAL VIA AN EPIGENETIC MECHANISM, ONLY ACTIVE AT A HIGH DOSE. 2000 17 6683 14 UV RADIATION AND AIR POLLUTION AS DRIVERS OF MAJOR AUTOIMMUNE CONDITIONS. AUTOIMMUNE DISEASES COMPRISE A VERY HETEROGENEOUS GROUP OF DISORDERS CHARACTERIZED BY DISRUPTIVE IMMUNE RESPONSES AGAINST SELF-ANTIGENS, CHRONIC MORBIDITY AND INCREASED MORTALITY. THE INCIDENCE AND PREVALENCE OF MAJOR AUTOIMMUNE CONDITIONS ARE PARTICULARLY HIGH IN THE WESTERN WORLD, AT NORTHERN LATITUDES, AND IN INDUSTRIALIZED COUNTRIES. THIS STUDY WILL MAINLY FOCUS ON FIVE MAJOR AUTOIMMUNE CONDITIONS, NAMELY TYPE 1 DIABETES, MULTIPLE SCLEROSIS, INFLAMMATORY BOWEL DISEASES, RHEUMATOID ARTHRITIS, AND AUTOIMMUNE THYROID DISORDERS. EPIDEMIOLOGICAL AND EXPERIMENTAL EVIDENCE SUGGESTS A PROTECTIVE ROLE OF SUNLIGHT EXPOSURE ON THE ETIOLOGY OF MAJOR AUTOIMMUNE CONDITIONS MEDIATED BY THE ENDOGENOUS PRODUCTION OF VITAMIN D AND NITRIC OXIDE. A HISTORICAL PERSPECTIVE SHOWS HOW THE RISE OF ANTHROPOGENIC AIR POLLUTANTS IS TEMPORALLY ASSOCIATED WITH DRAMATIC INCREASES IN INCIDENCE OF THESE CONDITIONS. THE SCATTERING CAUSED BY AMBIENT PARTICULATE MATTER AND THE PRESENCE OF TROPOSPHERIC OZONE CAN REDUCE THE ENDOGENOUS PRODUCTION OF VITAMIN D AND NITRIC OXIDE, WHICH ARE IMPLICATED IN MAINTAINING THE IMMUNE HOMEOSTASIS. AIR POLLUTANTS HAVE DIRECT DETRIMENTAL EFFECTS ON THE HUMAN BODY AND ARE DEEMED RESPONSIBLE OF AN INCREASINGLY HIGHER PORTION OF THE ANNUAL BURDEN OF HUMAN MORBIDITY AND MORTALITY. AIR POLLUTION CONTRIBUTES IN SYSTEMIC INFLAMMATION, ACTIVATES OXIDATIVE PATHWAYS, INDUCES EPIGENETIC ALTERATIONS, AND MODULATES THE FUNCTION AND PHENOTYPE OF DENDRITIC CELLS, TREGS, AND T-CELLS. IN THIS REVIEW, WE PROVIDE EPIDEMIOLOGICAL AND MECHANISTIC INSIGHTS REGARDING THE ROLE OF UV-MEDIATED EFFECTS IN IMMUNITY AND HOW ANTHROPIC-DERIVED AIR POLLUTION MAY AFFECT MAJOR AUTOIMMUNE CONDITIONS THROUGH DIRECT AND INDIRECT MECHANISMS. 2023 18 4383 17 MITOCHONDRIAL EPIGENETICS AND ENVIRONMENTAL HEALTH: MAKING A CASE FOR ENDOCRINE DISRUPTING CHEMICALS. RECENT STUDIES IMPLICATE MITOCHONDRIAL DYSFUNCTION IN THE DEVELOPMENT AND PROGRESSION OF NUMEROUS CHRONIC DISEASES, WHICH MAY BE PARTIALLY DUE TO MODIFICATIONS IN MITOCHONDRIAL DNA (MTDNA). THERE IS ALSO MOUNTING EVIDENCE THAT EPIGENETIC MODIFICATIONS TO MTDNA MAY BE AN ADDITIONAL LAYER OF REGULATION THAT CONTROLS MITOCHONDRIAL BIOGENESIS AND FUNCTION. SEVERAL ENVIRONMENTAL FACTORS (EG, SMOKING, AIR POLLUTION) HAVE BEEN ASSOCIATED WITH ALTERED MTDNA METHYLATION IN A HANDFUL OF MECHANISTIC STUDIES AND IN OBSERVATIONAL HUMAN STUDIES. HOWEVER, LITTLE IS UNDERSTOOD ABOUT OTHER ENVIRONMENTAL CONTAMINANTS THAT INDUCE MTDNA EPIGENETIC CHANGES. NUMEROUS ENVIRONMENTAL TOXICANTS ARE CLASSIFIED AS ENDOCRINE DISRUPTING CHEMICALS (EDCS). BEYOND THEIR ACTIONS ON HORMONAL PATHWAYS, EDC EXPOSURE IS ASSOCIATED WITH ELEVATED OXIDATIVE STRESS, WHICH MAY OCCUR THROUGH OR RESULT IN MITOCHONDRIAL DYSFUNCTION. ALTHOUGH ONLY A FEW STUDIES HAVE ASSESSED THE IMPACTS OF EDCS ON MTDNA METHYLATION, THE CURRENT REVIEW PROVIDES REASONS TO CONSIDER MTDNA EPIGENETIC DISRUPTION AS A MECHANISM OF ACTION OF EDCS AND REVIEWS POTENTIAL LIMITATIONS RELATED TO CURRENTLY AVAILABLE EVIDENCE. FIRST, THERE IS SUFFICIENT EVIDENCE THAT EDCS (INCLUDING BISPHENOLS AND PHTHALATES) DIRECTLY TARGET MITOCHONDRIAL FUNCTION, AND MORE DIRECT EVIDENCE IS NEEDED TO CONNECT THIS TO MTDNA METHYLATION. SECOND, THESE AND OTHER EDCS ARE POTENT MODULATORS OF NUCLEAR DNA EPIGENETICS, INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS. FINALLY, EDCS HAVE BEEN SHOWN TO DISRUPT SEVERAL MODULATORS OF MTDNA METHYLATION, INCLUDING DNA METHYLTRANSFERASES AND THE MITOCHONDRIAL TRANSCRIPTION FACTOR A/NUCLEAR RESPIRATORY FACTOR 1 PATHWAY. TAKEN TOGETHER, THESE STUDIES HIGHLIGHT THE NEED FOR FUTURE RESEARCH EVALUATING MTDNA EPIGENETIC DISRUPTION BY EDCS AND TO DETAIL SPECIFIC MECHANISMS RESPONSIBLE FOR SUCH DISRUPTIONS. 2020 19 653 17 BISPHENOL A, HYPERTENSION, AND CARDIOVASCULAR DISEASES: EPIDEMIOLOGICAL, LABORATORY, AND CLINICAL TRIAL EVIDENCE. BISPHENOL A (BPA) EXPOSURE HAS BECOME ONE OF THE MOST COMMON ENVIRONMENTAL CHEMICAL EXPOSURES IN HUMANS. THERE IS GROWING EVIDENCE REGARDING AN ASSOCIATION BETWEEN BPA EXPOSURE, HYPERTENSION, AND CARDIOVASCULAR DISEASES (CVD). IF BPA EXPOSURE IS INDEED ASSOCIATED WITH RAISED BLOOD PRESSURE AND CVD, IT WOULD BE A MAJOR PUBLIC HEALTH PROBLEM. THEREFORE, WE REVIEWED THE EPIDEMIOLOGICAL, LABORATORY, AND CLINICAL TRIAL EVIDENCE FOR AN ASSOCIATION BETWEEN BPA EXPOSURE, CVD, AND HYPERTENSION, AND DISCUSSED THE POSSIBLE MECHANISMS IN THIS ARTICLE. CROSS-SECTIONAL STUDIES IN VARIOUS ETHNICITIES SUGGESTED A POSSIBLE ASSOCIATION BETWEEN BPA EXPOSURE AND HYPERTENSION; THIS ASSOCIATION WAS SUPPORTED BY A PANEL STUDY AND A RANDOMIZED CLINICAL TRIAL. DESPITE THE DISCORDANCE AMONG CROSS-SECTIONAL STUDIES ABOUT AN ASSOCIATION BETWEEN BPA EXPOSURE AND CVD, A LONGITUDINAL STUDY SHOWS THAT BPA EXPOSURE IS A RISK FACTOR FOR CVD. THE EFFECTS OF BPA EXPOSURE SUCH AS ENDOCRINAL DISTURBANCE, INDUCTION OF OXIDATIVE STRESS AND INFLAMMATION, EPIGENETIC CHANGE, AND LINKS WITH OTHER CHRONIC DISEASES MAY HIGHLIGHT A POSSIBLE MECHANISM BETWEEN BPA EXPOSURE, CVD, AND HYPERTENSION. TO CLARIFY THE CAUSAL RELATIONSHIP, WELL-DESIGNED STUDIES ARE NEEDED IN THE FUTURE. 2016 20 4805 13 OBESITY AND METABOLIC COMORBIDITIES: ENVIRONMENTAL DISEASES? OBESITY AND METABOLIC COMORBIDITIES REPRESENT INCREASING HEALTH PROBLEMS. ENDOCRINE DISRUPTING COMPOUNDS (EDCS) ARE EXOGENOUS AGENTS THAT CHANGE ENDOCRINE FUNCTION AND CAUSE ADVERSE HEALTH EFFECTS. MOST EDCS ARE SYNTHETIC CHEMICALS; SOME ARE NATURAL FOOD COMPONENTS AS PHYTOESTROGENS. PEOPLE ARE EXPOSED TO COMPLEX MIXTURES OF CHEMICALS THROUGHOUT THEIR LIVES. EDCS IMPACT HORMONE-DEPENDENT METABOLIC SYSTEMS AND BRAIN FUNCTION. LABORATORY AND HUMAN STUDIES PROVIDE COMPELLING EVIDENCE THAT HUMAN CHEMICAL CONTAMINATION CAN PLAY A ROLE IN OBESITY EPIDEMIC. CHEMICAL EXPOSURES MAY INCREASE THE RISK OF OBESITY BY ALTERING THE DIFFERENTIATION OF ADIPOCYTES. EDCS CAN ALTER METHYLATION PATTERNS AND NORMAL EPIGENETIC PROGRAMMING IN CELLS. OXIDATIVE STRESS MAY BE INDUCED BY MANY OF THESE CHEMICALS, AND ACCUMULATING EVIDENCE INDICATES THAT IT PLAYS IMPORTANT ROLES IN THE ETIOLOGY OF CHRONIC DISEASES. THE INDIVIDUAL SENSITIVITY TO CHEMICALS IS VARIABLE, DEPENDING ON ENVIRONMENT AND ABILITY TO METABOLIZE HAZARDOUS CHEMICALS. A NUMBER OF GENES, ESPECIALLY THOSE REPRESENTING ANTIOXIDANT AND DETOXIFICATION PATHWAYS, HAVE POTENTIAL APPLICATION AS BIOMARKERS OF RISK ASSESSMENT. THE POTENTIAL HEALTH EFFECTS OF COMBINED EXPOSURES MAKE THE RISK ASSESSMENT PROCESS MORE COMPLEX COMPARED TO THE ASSESSMENT OF SINGLE CHEMICALS. TECHNIQUES AND METHODS NEED TO BE FURTHER DEVELOPED TO FILL DATA GAPS AND INCREASE THE KNOWLEDGE ON HARMFUL EXPOSURE COMBINATIONS. 2013