1 2938 76 GENETIC AND EPIGENETIC ALTERATIONS IN BARRETT'S ESOPHAGUS AND ESOPHAGEAL ADENOCARCINOMA. ESOPHAGEAL ADENOCARCINOMA (EAC) DEVELOPS FROM BARRETT'S ESOPHAGUS (BE), WHEREIN NORMAL SQUAMOUS EPITHELIA IS REPLACED BY SPECIALIZED INTESTINAL METAPLASIA IN RESPONSE TO CHRONIC GASTROESOPHAGEAL ACID REFLUX. BE CAN PROGRESS TO LOW- AND HIGH-GRADE DYSPLASIA, INTRAMUCOSAL, AND INVASIVE CARCINOMA. BOTH BE AND EAC ARE CHARACTERIZED BY LOSS OF HETEROZYGOSITY, ANEUPLOIDY, SPECIFIC GENETIC MUTATIONS, AND CLONAL DIVERSITY. GIVEN THE LIMITATIONS OF HISTOPATHOLOGY, GENOMIC AND EPIGENOMIC ANALYSES MAY IMPROVE THE PRECISION OF RISK STRATIFICATION. ASSAYS TO DETECT MOLECULAR ALTERATIONS ASSOCIATED WITH NEOPLASTIC PROGRESSION COULD BE USED TO IMPROVE THE PATHOLOGIC ASSESSMENT OF BE/EAC AND TO SELECT HIGH-RISK PATIENTS FOR MORE INTENSIVE SURVEILLANCE. 2015 2 4437 50 MOLECULAR EVOLUTION OF METAPLASIA TO ADENOCARCINOMA IN THE ESOPHAGUS. ESOPHAGEAL ADENOCARCINOMA (EAC) DEVELOPS FROM BARRETT'S ESOPHAGUS (BE), A CONDITION WHERE THE NORMAL SQUAMOUS EPITHELIA IS REPLACED BY SPECIALIZED INTESTINAL METAPLASIA IN RESPONSE TO CHRONIC GASTROESOPHAGEAL ACID REFLUX. IN A MINORITY OF INDIVIDUALS, BE CAN PROGRESS TO LOW- AND HIGH-GRADE DYSPLASIA AND EVENTUALLY TO INTRA-MUCOSAL AND THEN INVASIVE CARCINOMA. BE PROVIDES RESEARCHERS WITH A UNIQUE MODEL TO CHARACTERIZE THE PROCESS BY WHICH A CARCINOMA ARISES FROM ITS PRECURSOR LESION. MOLECULAR STUDIES OF BE HAVE DEMONSTRATED THAT IT IS NOT SIMPLY A METAPLASTIC TISSUE, BUT RATHER IT HARBORS FREQUENT ALTERATIONS THAT ARE ALSO PRESENT IN DYSPLASTIC BE AND IN EAC. BOTH BE AND EAC ARE CHARACTERIZED BY LOSS OF HETEROZYGOSITY, ANEUPLOIDY, SPECIFIC GENETIC MUTATIONS, AND CLONAL DIVERSITY. EPIGENETIC ABNORMALITIES, PRIMARY ALTERATIONS IN DNA METHYLATION, ARE ALSO FREQUENTLY SEEN IN BE AND EAC. CANDIDATE GENE AND ARRAY-BASED APPROACHES HAVE DEMONSTRATED THAT NUMEROUS TUMOR SUPPRESSOR GENES EXHIBIT ABERRANT PROMOTER METHYLATION, AND SOME OF THESE ALTERED GENES ARE ASSOCIATED WITH THE NEOPLASTIC PROGRESSION OF BE. IT HAS ALSO BEEN SHOWN THAT THE BE AND EAC EPIGENOMES ARE CHARACTERIZED BY HYPOMETHYLATION OF INTRAGENIC AND NON-CODING REGIONS RECENT STUDIES HAVE ALSO PROVIDED NEW INSIGHT INTO THE EVOLUTIONARY FORCES UNDERLYING THE MOLECULAR ALTERATIONS SEEN IN BE AND EAC AND INTO THE MOLECULAR PATHOGENESIS OF EAC. 2018 3 864 25 CHROMOSOMAL INSTABILITY IN ORAL SQUAMOUS CELL CARCINOMA. ORAL SQUAMOUS CELL CARCINOMA (OSCC) DEMONSTRATES AN INCREASING RATE DUE TO HIGH RISK HUMAN PAPILLOMA VIRUS (HR-HPV) PERSISTENT INFECTION, AND ALSO TO CHRONIC CIGARETTE AND ALCOHOL CONSUMPTION. GROSS CHROMOSOMAL ALTERATIONS (POLYSOMY, ANEUPLOIDY, INTRA-CHROMOSOME REARRANGEMENTS) AND SPECIFIC GENE ABERRATIONS SUCH AS AMPLIFICATIONS, DELETIONS, POINT MUTATIONS COMBINED OR NOT WITH EPIGENETIC ONES (PROMOTER METHYLATIONS AND MIRNA DEREGULATIONS) ARE RESPONSIBLE FOR THE PROGRESSIVE TRANSFORMATION OF NORMAL SQUAMOUS CELL EPITHELIA TO THE CORRESPONDING MALIGNANT. CHROMOSOMAL INSTABILITY (CI) -BASED ON STRUCTURAL OR NUMERICAL ABNORMALITIES- LEADS TO SPECIFIC ABNORMAL KARYOTYPES COMBINED OR NOT WITH FUNCTIONAL SUPPRESSOR GENE INACTIVATION AND ONCOGENE OVERACTIVATION IN SOLID MALIGNANCIES, INCLUDING OSCC. EXTENSIVE CYTOGENETIC ANALYSES HAVE SHOWN THAT GROSS ALTERATIONS (GAINS/LOSSES) IN CHROMOSOMES 3, 4, 7, 8, 9, 11, 14, 17, 18, 19 AND ALSO 20 FORM DIFFERENT CI PATTERNS IN OSCC, WHICH IN CONJUNCTION WITH AN AGGRESSIVE PHENOTYPE (PRESENCE OF LYMPH NODAL METASTASIS) NEGATIVELY AFFECT THE PROGNOSIS IN THE CORRESPONDING PATIENTS. IN THE MAJORITY OF OSCC CASES, LOSS OF CHROMOSOMAL BANDS ARE ALMOST EQUALLY DETECTED COMPARED WITH GAINS REGARDING THE CHROMOSOMES REFERRED ABOVE. IN THE CURRENT SPECIAL MOLECULAR PAPER WE EXPLORED THE ROLE OF CI IN THE PROGRESSION AND BIOLOGICAL BEHAVIOR OF OSCCS. 2018 4 4387 23 MITOTIC DYSFUNCTION ASSOCIATED WITH AGING HALLMARKS. AGING IS A BIOLOGICAL PROCESS CHARACTERIZED BY THE PROGRESSIVE DETERIORATION OF PHYSIOLOGICAL FUNCTIONS KNOWN TO BE THE MAIN RISK FACTOR FOR CHRONIC DISEASES AND DECLINING HEALTH. THERE HAS BEEN AN EMERGING CONNECTION BETWEEN AGING AND ANEUPLOIDY, AN ABERRANT NUMBER OF CHROMOSOMES, EVEN THOUGH THE MOLECULAR MECHANISMS BEHIND AGE-ASSOCIATED ANEUPLOIDY REMAIN LARGELY UNKNOWN. IN RECENT YEARS, SEVERAL GENETIC PATHWAYS AND BIOCHEMICAL PROCESSES CONTROLLING THE RATE OF AGING HAVE BEEN IDENTIFIED AND PROPOSED AS AGING HALLMARKS. PRIMARY HALLMARKS THAT CAUSE THE ACCUMULATION OF CELLULAR DAMAGE INCLUDE GENOMIC INSTABILITY, TELOMERE ATTRITION, EPIGENETIC ALTERATIONS AND LOSS OF PROTEOSTASIS (LOPEZ-OTIN ET AL., CELL 153:1194-1217, 2013). HERE WE REVIEW THE PROVOCATIVE LINK BETWEEN THESE AGING HALLMARKS AND THE LOSS OF CHROMOSOME SEGREGATION FIDELITY DURING CELL DIVISION, WHICH COULD SUPPORT THE CORRELATION BETWEEN AGING AND ANEUPLOIDY SEEN OVER THE PAST DECADES. SECONDLY, WE REVIEW THE SYSTEMIC IMPACTS OF ANEUPLOIDY IN CELL PHYSIOLOGY AND EMPHASIZE HOW THESE INCLUDE SOME OF THE PRIMARY HALLMARKS OF AGING. BASED ON THE EVIDENCE, WE PROPOSE A MUTUAL CAUSALITY BETWEEN AGING AND ANEUPLOIDY, AND SUGGEST MODULATION OF MITOTIC FIDELITY AS A POTENTIAL MEANS TO AMELIORATE HEALTHY LIFESPAN. 2017 5 1975 27 EPIGENETIC ALTERATIONS FROM BARRETT'S ESOPHAGUS TO ESOPHAGEAL ADENOCARCINOMA. BARRETT'S ESOPHAGUS (BE) IS A DISEASE ENTITY THAT IS A SEQUELA OF CHRONIC GASTROESOPHAGEAL REFLUX DISEASE THAT MAY RESULT IN ESOPHAGEAL ADENOCARCINOMA (EAC) DUE TO COLUMNAR EPITHELIAL DYSPLASIA. THE HISTOLOGICAL DEGREE OF DYSPLASIA IS THE SOLE BIOMARKER FREQUENTLY UTILIZED BY CLINICIANS. HOWEVER, THE COST OF ENDOSCOPY AND THE FACT THAT THE DEGREE OF DYSPLASIA DOES NOT PROGRESS IN MANY PATIENTS WITH BE DIMINISH THE EFFECTIVENESS OF HISTOLOGICAL GRADING AS A PERFECT BIOMARKER. MULTIPLE OR MORE QUANTITATIVE BIOMARKERS ARE REQUIRED BY CLINICIANS SINCE EARLY DIAGNOSIS IS CRUCIAL IN ESOPHAGEAL ADENOCANCERS, WHICH HAVE A HIGH MORTALITY RATE. THE PRESENCE OF EPIGENETIC FACTORS IN THE EARLY STAGES OF THIS NEOPLASTIC TRANSFORMATION HOLDS PROMISE AS A PREDICTIVE BIOMARKER. IN THIS REVIEW, CURRENT STUDIES ON DNA METHYLATIONS, HISTONE MODIFICATIONS, AND NONCODING RNAS (MIRNAS) THAT HAVE BEEN DISCOVERED DURING THE PROGRESSION FROM BE DYSPLASIA TO EAC WERE COLLATED. 2023 6 4438 28 MOLECULAR FINDINGS IN BARRETT'S EPITHELIUM. BARRETT'S METAPLASIA IS A PREMALIGNANT CONDITION AND REMAINS THE NUMBER ONE RISK FACTOR FOR DEVELOPING ADENOCARCINOMA. THE HISTOLOGIC CHANGES LEADING TO ADENOCARCINOMA ARE ACCOMPANIED BY GENETIC DISTURBANCES OF THE EPITHELIAL CELLS ITSELF AS WELL AS THE SURROUNDING STROMA. GENETIC AND EPIGENETIC EVENTS AFFECT THE CELL CYCLE, LEADING TO GROWTH SELF-SUFFICIENCY AND IGNORATION OF ANTIGROWTH SIGNALS. THE BALANCE OF CELL TURNOVER IS INSTABLE BY AVOIDANCE OF APOPTOSIS AND A GENERAL LIMITLESS OF THE REPLICATIVE POTENTIAL OF THE (MUTATED) STEM CELLS. SUSTAINED ANGIOGENESIS, NOT ONLY A CONSEQUENCE OF CHRONIC INFLAMMATION, MAY PRECEDE INVASION OF GENETICALLY INSTABLE (ANEUPLOID) CELLS. THE PRINCIPAL GENETIC CHANGES IN BARRETT'S CARCINOGENESIS ARE COMPARABLE TO THOSE KNOWN FROM OTHER EPITHELIAL MALIGNANCIES. LOSS OF P16 GENE EXPRESSION (BY DELETION OR HYPERMETHYLATION), THE LOSS OF P53 EXPRESSION (BY MUTATION AND DELETION), THE INCREASE IN CYCLIN EXPRESSION, AND THE LOSSES OF RB, APC AS WELL AS VARIOUS CHROMOSOMAL LOCI HAVE BEEN REPORTED. SINCE THESE GENETIC OR EPIGENETIC ALTERATIONS ARE NEITHER TUMOR NOR STAGE SPECIFIC, THEY COULD NOT GAIN DIAGNOSTIC SIGNIFICANCE AS BIOMARKERS UNTIL NOW. 2004 7 1099 28 COLONIC CARCINOGENESIS IN IBD: MOLECULAR EVENTS. PATIENTS WITH ULCERATIVE COLITIS (UC) AND CROHN'S DISEASE (CD) ARE AT INCREASED RISK OF DEVELOPING INTESTINAL CANCERS VIA MECHANISMS THAT REMAIN INCOMPLETELY UNDERSTOOD. SEVERAL EVIDENCES SUGGEST A CAUSAL LINK BETWEEN CHRONIC INFLAMMATION AND THE DEVELOPMENT OF CANCER IN THE GASTROINTESTINAL TRACT. IN FACT, PATIENTS WITH UC ARE EXPOSED TO REPEATED EPISODES OF INFLAMMATION THAT PREDISPOSE TO VARIOUS TUMORIGENIC EVENTS AND THE SEQUENCE OF THESE EVENTS ARE DIFFERENT FROM THOSE THAT CONTRIBUTE TO DEVELOP A SPORADIC COLORECTAL CANCER. IN UC CARCINOGENESIS THE EARLY EVENTS ARE REPRESENTED BY DNA METHYLATION THAT PRODUCE AN INHIBITION OF ONCO-SUPPRESSOR GENES, MUTATION OF P53, ANEUPLOIDY AND MICROSATELLITE INSTABILITY. HYPERMETHYLATION OF TUMOR SUPPRESSORS AND DNA MISMATCH REPAIR GENE PROMOTER REGIONS, IS AN EPIGENETIC MECHANISM OF GENE SILENCING THAT CONTRIBUTES TO TUMORIGENESIS AND MIGHT REPRESENT THE FIRST STEP IN INFLAMMATORY CARCINOGENESIS. P53 IS FREQUENTLY MUTATED IN THE EARLY STAGES OF UC-ASSOCIATED CANCER, IN 33-67% OF PATIENTS WITH DYSPLASIA AND IN 83-95% OF UC RELATED CANCER PATIENTS. MOREOVER, ANEUPLOIDY IS AN INDEPENDENT RISK FACTOR FOR FORTHCOMING CARCINOGENESIS IN UC FINALLY, THE INCONSISTENCY BETWEEN THE HIGH CUMULATIVE RATE OF DYSPLASIA IN UC AND THE RELATIVELY LOWER INCIDENCE OF INVASIVE CANCER RAISES THE QUESTION ABOUT THE MECHANISMS OF IMMUNOSURVEILLANCE THAT MAY PREVENT MALIGNANT PROGRESSION OF NEOPLASM IN THE COLON IN MOST CASES. CO-STIMULATORY MOLECULE CD80 UP-REGULATION IN COLONIC MUCOSA IN UC DYSPLASIA MAY BE ONE OF THESE MECHANISM. 2011 8 563 42 BARRETT'S ESOPHAGUS: CAN BIOMARKERS PREDICT PROGRESSION TO MALIGNANCY? BARRETT'S ESOPHAGUS (BE) IS ONE OF THE MOST COMMON PREMALIGNANT LESIONS AND CAN PROGRESS TO ESOPHAGEAL ADENOCARCINOMA. IT IS CHARACTERIZED HISTOLOGICALLY BY A SPECIALIZED INTESTINAL METAPLASIA THAT REPLACES THE SQUAMOUS EPITHELIUM OF THE DISTAL ESOPHAGUS, AND IS ASSOCIATED WITH CHRONIC GASTROESOPHAGEAL REFLUX DISEASE AND OBESITY. SIMILAR TO THE ADENOMA-CARCINOMA SEQUENCE OF COLORECTAL CARCINOMAS, ESOPHAGEAL ADENOCARCINOMA DEVELOPS THROUGH PROGRESSION FROM BE TO LOW- AND HIGH-GRADE DYSPLASIA, THEN TO ADENOCARCINOMA WITH ACCUMULATION OF GENETIC AND EPIGENETIC ABNORMALITIES. THE EXACT MALIGNANCY POTENTIAL OF BE IS UNCERTAIN. DYSPLASIA IS THE MOST PREDICTIVE MARKER FOR RISK OF ESOPHAGEAL ADENOCARCINOMA, WHEREAS ENDOSCOPIC AND HISTOLOGICAL DIAGNOSES ARE STILL THE GOLD STANDARD FOR SURVEILLANCE OF PATIENTS WITH BE. HOWEVER, BOTH ARE LIMITED, EITHER BY SAMPLING ERRORS IN BIOPSIES OR BY DIFFERENCES IN HISTOLOGICAL INTERPRETATION. SEVERAL STUDIES HAVE IDENTIFIED CANDIDATE BIOMARKERS THAT MAY HAVE PREDICTIVE VALUE AND MAY SERVE AS ADDITIONAL FACTORS FOR THE RISK ASSESSMENT OF ESOPHAGEAL ADENOCARCINOMA. THIS REVIEW DISCUSSES THE ROLE OF BIOMARKERS IN THE PROGRESSION FROM BE TO ADENOCARCINOMA, FOCUSING ON CLINICAL AND MOLECULAR MARKERS. 2008 9 2015 32 EPIGENETIC BIOMARKERS IN ESOPHAGEAL CANCER. THE ABERRANT DNA METHYLATION OF TUMOR SUPPRESSOR GENES IS WELL DOCUMENTED IN ESOPHAGEAL CANCER, INCLUDING ADENOCARCINOMA (EAC) AND SQUAMOUS CELL CARCINOMA (ESCC) AS WELL AS IN BARRETT'S ESOPHAGUS (BE), A PRE-MALIGNANT CONDITION THAT IS ASSOCIATED WITH CHRONIC ACID REFLUX. BE IS A WELL-RECOGNIZED RISK FACTOR FOR THE DEVELOPMENT OF EAC, AND CONSEQUENTLY THE STANDARD OF CARE IS FOR INDIVIDUALS WITH BE TO BE PLACED IN ENDOSCOPIC SURVEILLANCE PROGRAMS AIMED AT DETECTING EARLY HISTOLOGIC CHANGES THAT ASSOCIATE WITH AN INCREASED RISK OF DEVELOPING EAC. YET BECAUSE THE ABSOLUTE RISK OF EAC IN INDIVIDUALS WITH BE IS MINIMAL, A CLINICAL NEED IN THE MANAGEMENT OF BE IS THE IDENTIFICATION OF ADDITIONAL RISK MARKERS THAT WILL INDICATE INDIVIDUALS WHO ARE AT A SIGNIFICANT ABSOLUTE RISK OF EAC SO THAT THEY MAY BE SUBJECTED TO MORE INTENSIVE SURVEILLANCE. THE BEST CURRENTLY AVAILABLE RISK MARKER IS THE DEGREE OF DYSPLASIA IN ENDOSCOPIC BIOPSIES FROM THE ESOPHAGUS; HOWEVER, THIS MARKER IS SUBOPTIMAL FOR A VARIETY OF REASONS. TO DATE, THERE ARE NO MOLECULAR BIOMARKERS THAT HAVE BEEN TRANSLATED TO WIDESPREAD CLINICAL PRACTICE. THE SEARCH FOR BIOMARKERS, INCLUDING HYPERMETHYLATED GENES, FOR EITHER THE DIAGNOSIS OF BE, EAC, OR ESCC OR FOR RISK STRATIFICATION FOR THE DEVELOPMENT OF EAC IN THOSE WITH BE IS CURRENTLY AN AREA OF ACTIVE RESEARCH. IN THIS REVIEW, WE SUMMARIZE THE STATUS OF IDENTIFIED CANDIDATE EPIGENETIC BIOMARKERS FOR BE, EAC, AND ESCC. MOST OF THESE ABERRANTLY METHYLATED GENES HAVE BEEN DESCRIBED IN THE CONTEXT OF EARLY DETECTION OR DIAGNOSTIC MARKERS; OTHERS MIGHT PROVE USEFUL FOR ESTIMATING PROGNOSIS OR PREDICTING RESPONSE TO TREATMENT. FINALLY, SPECIAL ATTENTION WILL BE PAID TO SOME OF THE CHALLENGES THAT MUST BE OVERCOME IN ORDER TO DEVELOP CLINICALLY USEFUL ESOPHAGEAL CANCER BIOMARKERS. 2014 10 2843 24 FREQUENT CPG ISLAND METHYLATION IN PRECURSOR LESIONS AND EARLY GASTRIC ADENOCARCINOMAS. GASTRIC CARCINOGENESIS INVOLVES MULTIPLE GENETIC AND EPIGENETIC ALTERATIONS. EPIGENETIC SILENCING OF TUMOR-RELATED GENES DUE TO CPG ISLAND METHYLATION (CIM) HAS BEEN RECENTLY REPORTED IN GASTRIC CANCER, BUT THE ROLE IN PRECURSOR LESIONS IS NOT WELL UNDERSTOOD. WE ANALYSED THE METHYLATION STATUS OF THE TUMOR SUPPRESSOR GENE P16, THE DNA MISMATCH REPAIR GENE HMLH1, AND FOUR CPG ISLANDS (MINT1, MINT2, MINT25, AND MINT31) USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION IN 35 POLYPOID ADENOMAS AND 46 FLAT DYSPLASIAS UNASSOCIATED WITH CARCINOMA, 34 EARLY ADENOCARCINOMAS (T1N0M0) AND ASSOCIATED ADENOMAS/DYSPLASIAS, AND CORRESPONDING ADJACENT NON-NEOPLASTIC MUCOSA. THE EXTENT OF CIM WAS DEFINED BY THE FRACTION OF METHYLATED LOCI (METHYLATION INDEX), AND COMPARED WITH PREVIOUSLY CHARACTERIZED GENETIC ALTERATIONS (MICROSATELLITE INSTABILITY (MSI) AND APC GENE MUTATION). WE FOUND THAT METHYLATION OF P16 WAS MORE FREQUENT IN ADENOCARCINOMA-ASSOCIATED DYSPLASIAS/ADENOMAS (29%) AND ADENOCARCINOMAS (44%) AS COMPARED TO FLAT DYSPLASIAS (4%) AND ADENOMAS (18%) UNASSOCIATED WITH ADENOCARCINOMA (P=0.001). THE MEAN METHYLATION INDEX INCREASED FROM NORMAL/CHRONIC GASTRITIS (CG) MUCOSA (0.09) TO INTESTINAL METAPLASIA (IM) (0.16), FLAT DYSPLASIAS (0.40) OR POLYPOID ADENOMAS (0.41) UNASSOCIATED WITH CARCINOMA, DYSPLASIAS/ADENOMAS ASSOCIATED WITH CARCINOMA (0.44), AND ADENOCARCINOMAS (0.44). THERE WAS NO DIFFERENCE IN FREQUENCIES OF HIGH-LEVEL CPG ISLAND METHYLATION (CIM-H, METHYLATION INDEX > OR =0.5) AMONG FLAT DYSPLASIAS (50%) AND POLYPOID ADENOMAS (51%) UNASSOCIATED WITH CARCINOMA, DYSPLASIAS/ADENOMAS ASSOCIATED WITH ADENOCARCINOMA (47%), AND ADENOCARCINOMA (47%). CIM-H WAS PRESENT IN 15% OF IM, BUT NOT IN NORMAL/CG MUCOSA. THERE WAS A SIGNIFICANT CORRELATION BETWEEN METHYLATION OF HMLH1 AND HIGH-LEVEL OF MICROSATELLITE INSTABILITY (MSI-H): METHYLATION OF HMLH1 WAS PRESENT IN 71% OF MSI-H TUMORS, BUT ONLY 8% OF MSI-LOW TUMORS AND 13% OF MICROSATELLITE-STABLE TUMORS (P=0.0001). THERE WAS NO STATISTICAL DIFFERENCE BETWEEN METHYLATION INDEX AND APC MUTATION. OUR RESULTS INDICATE THAT CONCURRENT PROMOTER METHYLATION IS AN EARLY AND FREQUENT EVENT IN GASTRIC TUMORIGENESIS, INCLUDING BOTH MSI-H AND MICROSATELLITE-STABLE NEOPLASMS. METHYLATION OF THE P16 GENE MAY CONTRIBUTE TO THE MALIGNANT TRANSFORMATION OF GASTRIC PRECURSOR LESIONS. 2004 11 732 19 CANCER DRUG RESISTANCE: THE CENTRAL ROLE OF THE KARYOTYPE. CURRENT GENETIC AND EPIGENETIC THEORIES OF CANCER-SPECIFIC DRUG RESISTANCE DO NOT ADEQUATELY EXPLAIN: (I) THE KARYOTYPIC CHANGES THAT COINCIDE WITH RESISTANCE, (II) THE HIGH RATES AT WHICH CANCER CELLS ACQUIRE AND ENHANCE RESISTANCE COMPARED TO THE RATES OF CONVENTIONAL MUTATION, (III) THE WIDE RANGES OF RESISTANCE SUCH AS MULTIDRUG RESISTANCE, (IV) THE FREQUENT OCCURRENCE OF INTRINSIC DRUG RESISTANCE. WE HAVE RECENTLY PROPOSED, THAT SPECIFIC KARYOTYPIC ALTERATIONS ARE SUFFICIENT FOR DRUG RESISTANCE VIA NEW TRANSCRIPTOMES OF COOPERATIVE GENES, INDEPENDENT OF GENE MUTATION. THIS MECHANISM GENERATES NEW PHENOTYPES JUST LIKE TRISOMY 21 GENERATES DOWN SYNDROME. THESE KARYOTYPIC CHANGES ARE GENERATED BY CANCER-SPECIFIC ANEUPLOIDY AUTOCATALYTICALLY, BECAUSE ANEUPLOIDY DESTABILIZES THE KARYOTYPE BY MISBALANCING TEAMS OF PROTEINS THAT SYNTHESIZE, REPAIR AND SEGREGATE CHROMOSOMES. EVIDENCE FOR THIS CHROMOSOMAL MECHANISM IS AS FOLLOWS: (I) RESISTANCE IS PROPORTIONAL TO THE NUMBER OF CLONAL CHROMOSOMAL ALTERATIONS COMPARED TO DRUG-SENSITIVE PRECURSORS. (II) THE HIGH RATES AT WHICH CANCER CELLS ACQUIRE DRUG RESISTANCE ARE COMPARABLE WITH THE RATES, AS HIGH AS 10(-2) PER CELL GENERATION, AT WHICH THEIR KARYOTYPES CHANGE-DIMMING HOPES FOR GENE-SPECIFIC THERAPIES. (III) MULTIDRUG RESISTANCE PROBABLY REFLECTS UN-SELECTED TRANSCRIPTOMES OF KARYOTYPES SELECTED FOR RESISTANCE AGAINST SPECIFIC DRUGS. (IV) INTRINSIC DRUG RESISTANCE PROBABLY REFLECTS UNSELECTED TRANSCRIPTOMES OF KARYOTYPES SELECTED FOR ONCOGENICITY. WE ALSO ADDUCE EVIDENCE THAT RESISTANCE OF CHRONIC MYELOID LEUKEMIA AGAINST THE DRUG IMATINIB IS CHROMOSOMAL, ALTHOUGH IT IS WIDELY BELIEVED TO BE DUE TO MUTATION OF A KINASE. 2007 12 4134 31 MECHANISMS OF HUMAN HEPATOCARCINOGENESIS. THE MAJOR RISK FACTORS AND ETIOLOGICAL AGENTS RESPONSIBLE FOR DEVELOPMENT OF HEPATOCELLULAR CARCINOMA IN HUMANS HAVE BEEN IDENTIFIED AND CHARACTERIZED. AMONG THESE ARE CHRONIC INFECTION WITH HEPATITIS B VIRUS OR HEPATITIS C VIRUS, EXPOSURE TO AFLATOXIN B1, AND CIRRHOSIS OF ANY ETIOLOGY (INCLUDING ALCOHOLIC CIRRHOSIS AND CIRRHOSIS ASSOCIATED WITH GENETIC LIVER DISEASES). BOTH CHRONIC HEPATITIS AND CIRRHOSIS REPRESENT MAJOR PRENEOPLASTIC CONDITIONS OF THE LIVER AS THE MAJORITY OF HEPATOCELLULAR CARCINOMAS ARISE IN THESE PATHOLOGICAL SETTINGS. HEPATOCARCINOGENESIS REPRESENTS A LINEAR AND PROGRESSIVE PROCESS IN WHICH SUCCESSIVELY MORE ABERRANT MONOCLONAL POPULATIONS OF HEPATOCYTES EVOLVE. REGENERATIVE HEPATOCYTES IN FOCAL LESIONS IN THE INFLAMED LIVER (CHRONIC HEPATITIS OR CIRRHOSIS) GIVE RISE TO HYPERPLASTIC HEPATOCYTE NODULES, AND THESE PROGRESS TO DYSPLASTIC NODULES, WHICH ARE THOUGHT TO BE THE DIRECT PRECURSOR OF HEPATOCELLULAR CARCINOMA. IN MOST CASES, THE NEOPLASTIC TRANSFORMATION OF HEPATOCYTES RESULTS FROM ACCUMULATION OF GENETIC DAMAGE DURING THE REPETITIVE CELLULAR PROLIFERATION THAT OCCURS IN THE INJURED LIVER IN RESPONSE TO PARACRINE GROWTH FACTOR AND CYTOKINE STIMULATION. HEPATOCELLULAR CARCINOMAS EXHIBIT NUMEROUS GENETIC ABNORMALITIES (INCLUDING CHROMOSOMAL DELETIONS, REARRANGEMENTS, ANEUPLOIDY, GENE AMPLIFICATIONS, AND MUTATIONS), AS WELL AS EPIGENETIC ALTERATIONS (INCLUDING MODULATION OF DNA METHYLATION). THESE GENETIC AND EPIGENETIC ALTERATIONS COMBINE TO ACTIVATE POSITIVE MEDIATORS OF CELLULAR PROLIFERATION (INCLUDING CELLULAR PROTO-ONCOGENES AND THEIR MITOGENIC SIGNALING PATHWAYS) AND INACTIVATE NEGATIVE MEDIATORS OF CELLULAR PROLIFERATION (INCLUDING TUMOR SUPPRESSOR GENES), RESULTING IN CELLS WITH AUTONOMOUS GROWTH POTENTIAL. HOWEVER, HEPATOCELLULAR CARCINOMAS EXHIBIT A HIGH DEGREE OF GENETIC HETEROGENEITY, SUGGESTING THAT MULTIPLE MOLECULAR PATHWAYS MAY BE INVOLVED IN THE GENESIS OF SUBSETS OF HEPATOCELLULAR NEOPLASMS. CONTINUED INVESTIGATION OF THE MECHANISMS OF HEPATOCARCINOGENESIS WILL REFINE OUR CURRENT UNDERSTANDING OF THE MOLECULAR AND CELLULAR BASIS FOR NEOPLASTIC TRANSFORMATION IN LIVER, ENABLING THE DEVELOPMENT OF EFFECTIVE STRATEGIES FOR PREVENTION AND/OR MORE EFFECTIVE TREATMENT OF HEPATOCELLULAR CARCINOMA. 2003 13 5181 26 PREMALIGNANT LESIONS IN GASTRIC CANCER. DESPITE A PLATEAU IN INCIDENCE, GASTRIC CANCER IS ONE OF THE MOST COMMON CANCERS WORLDWIDE AND CAUSES CONSIDERABLE MORBIDITY AND MORTALITY. PREMALIGNANT GASTRIC LESIONS ARE WELL KNOWN RISK FACTORS FOR THE DEVELOPMENT OF INTESTINAL-TYPE GASTRIC ADENOCARCINOMAS. IN THIS MULTISTEP MODEL OF GASTRIC CARCINOGENESIS, HELICOBACTER PYLORI CAUSES CHRONIC ACTIVE INFLAMMATION OF THE GASTRIC MUCOSA, WHICH SLOWLY PROGRESSES THROUGH THE PREMALIGNANT STAGES OF ATROPHIC GASTRITIS, INTESTINAL METAPLASIA, AND ADENOMA/DYSPLASIA TO GASTRIC CARCINOMA. THIS PROGRESSION IS PARALLELED BY A STEPWISE ACCUMULATION OF MULTIPLE GENETIC AND EPIGENETIC ABNORMALITIES. DETECTION, TREATMENT, AND MOLECULAR ANALYSES OF PREMALIGNANT LESIONS MAY THUS PROVIDE A BASIS FOR GASTRIC CANCER PREVENTION. THIS REVIEW DESCRIBES AN OVERVIEW OF CURRENT KNOWLEDGE ON PREMALIGNANT GASTRIC LESIONS. IT ALSO REVIEWS THE ISSUE OF SURVEILLANCE OF PATIENTS WITH PREMALIGNANT LESIONS IN ORDER TO IMPROVE THE SURVIVAL OF PATIENTS WITH GASTRIC CANCER. 2010 14 5180 20 PREMALIGNANT CONDITIONS OF GASTRIC CANCER. PREMALIGNANT LESIONS OF GASTRIC CANCER ENCOMPASS A VARIETY OF CONDITIONS SUCH AS CHRONIC GASTRITIS, INTESTINAL METAPLASIA AND DYSPLASIA, IN WHICH ELEVATED RISK OF DEVELOPING GASTRIC CANCER HAVE BEEN DOCUMENTED. AMONG THEM, INTESTINAL METAPLASIA IS FREQUENTLY ENCOUNTERED IN OUR DAILY ENDOSCOPIC EXAMINATION, YET ITS CLINICAL SIGNIFICANCE IS OFTEN UNDERESTIMATED DESPITE OF A NUMBER OF REPORTS DEMONSTRATING GENETIC AND EPIGENETIC ALTERATIONS IN THE INTESTINAL METAPLASTIC MUCOSA. IN THIS REVIEW, I WILL DESCRIBE THE MOLECULAR MECHANISMS OF PHENOTYPIC CHANGES FROM GASTRIC MUCOSA TO INTESTINAL METAPLASIA BASED ON OUR ANALYSIS OF MOUSE MODEL OF INTESTINAL METAPLASIA GENERATED BY ECTOPIC EXPRESSION OF CDX2 IN CONJUNCTION WITH THE STUDIES WITH HUMAN INTESTINAL METAPLASIA. 2013 15 2996 14 GENETIC PROFILE AND MICROSATELLITE INSTABILITY IN A CASE OF SECONDARY ESOPHAGEAL SQUAMOUS CELL CARCINOMA 12 YEARS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR APLASTIC ANEMIA. WE REPORT ON A 16-YEAR-OLD JAPANESE BOY IN WHOM AN ESOPHAGEAL SQUAMOUS CELL CARCINOMA (ESCC) DEVELOPED 12 YEARS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WAS PERFORMED FOR APLASTIC ANEMIA. A HIGH FREQUENCY OF MICROSATELLITE INSTABILITY WAS DETECTED IN SAMPLES OF ESCC. MOREOVER, THE DETECTION OF PATHOGENIC VARIANTS, INCLUDING SINGLE NUCLEOTIDE SUBSTITUTION OF TP53 (C.346C>T) AND BRCA2 (C.6952C>T) AND SPLICING OF KDM6A (C.1194+2T>G), SUGGEST THAT THE DEVELOPMENT OF ESCC IN THE PATIENT WAS TRIGGERED BY IMPAIRMENT OF CHECKPOINT AND REPAIR FOR DNA DAMAGE AND EPIGENETIC MODIFICATION THROUGH ACCUMULATION OF GENE MUTATIONS INDUCED BY CHRONIC GRAFT-VERSUS-HOST DISEASE AND PROLONGED ADMINISTRATION OF TACROLIMUS. 2020 16 562 28 BARRETT ESOPHAGUS: HISTORY, DEFINITION AND ETIOPATHOGENY. THE INJURY OF THE ESOPHAGEAL EPITHELIUM MAY BE DETERMINED BY THE REFLUX OF THE GASTRIC ACID IN THE ESOPHAGUS. BARRETT'S ESOPHAGUS (BE) IS CHARACTERIZED BY THE REPLACEMENT OF THE NORMAL SQUAMOUS EPITHELIUM WITH THE COLUMNAR EPITHELIUM, WHEN THE HEALING OF THE LESION OCCURS. ACCORDING TO SOME STUDIES, THE INCIDENCE OF THE ESOPHAGEAL ADENOCARCINOMA IN PATIENTS WITH BE IS OF ABOUT 0,5% PER YEAR. THE TERM BARRETT'S ESOPHAGUS IS SUBJECTED TO INTERPRETATION NOWADAYS, SO IT LACKS THE CLARITY NEEDED FOR THE CLINICAL AND SCIENTIFIC COMMUNICATION ON THE SUBJECT OF COLUMNAR METAPLASIA OF THE ESOPHAGEAL MUCOSA. THE MAJOR PATHOGENETIC FACTOR IN THE DEVELOPMENT OF BE IS REPRESENTED BY THE REFLUX DISEASE. THE CELLULAR ORIGIN OF BE IS CONTROVERSIAL AND IT REPRESENTS AN ISSUE THAT NEEDS TO BE RESOLVED BECAUSE IT WILL HAVE IMPLICATIONS IN THE PUTATIVE MOLECULAR MECHANISMS UNDERLYING THE METAPLASTIC PROCESS. THE EPIGENETIC OR GENETIC CHANGES, WHICH ALTER PROTEIN EXPRESSION, FUNCTION, AND/ OR ACTIVITY, IN POST-MITOTIC CELLS TO DRIVE TRANSDIFFERENTIATION OR IN STEM/ PROGENITOR CELLS SUCH THAT THEY ARE REPROGRAMMED TO DIFFERENTIATE INTO COLUMNAR RATHER THAN SQUAMOUS CELLS, ARE DRIVEN BY THE INFLAMMATORY ENVIRONMENT CREATED BY CHRONIC REFLUX. IN ORDER TO BE ABLE TO DEVELOP BETTER THERAPEUTIC STRATEGIES FOR THE PATIENTS WITH THIS DISEASE, AN INCREASING INTEREST IN UNDERSTANDING THE PATHOGENESIS OF BE AT THE CELLULAR AND MOLECULAR LEVEL PRESENTS THESE DAYS. 2014 17 2943 19 GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR SUPPRESSOR AND TUMOR-RELATED GENES IN GASTRIC CANCER. BOTH GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR SUPPRESSOR AND TUMOR-RELATED GENES INVOLVED IN THE PATHOGENESIS OF GASTRIC CANCER ARE REVIEWED HERE, AND MOLECULAR PATHWAYS OF GASTRIC CARCINOGENESIS ARE PROPOSED. GASTRIC CARCINOMAS ARE BELIEVED TO EVOLVE FROM NATIVE GASTRIC MUCOSA OR INTESTINAL METAPLASTIC MUCOSA THAT UNDERGOES GENETIC AND EPIGENETIC ALTERATIONS INVOLVING EITHER THE SUPPRESSOR PATHWAY (DEFECTS IN TUMOR SUPPRESSOR GENES) OR MUTATOR PATHWAY (DEFECTS IN DNA MISMATCH REPAIR GENES). METHYLATION OF E-CADHERIN IN NATIVE GASTRIC MUCOSA RESULTS IN UNDIFFERENTIATED CARCINOMAS (SUPPRESSOR PATHWAY), WHILE METHYLATION OF HMLHI RESULTS IN DIFFERENTIATED FOVEOLAR-TYPE CARCINOMAS (MUTATOR PATHWAY). THE MAJORITY OF DIFFERENTIATED GASTRIC CARCINOMAS HOWEVER, ARISE FROM INTESTINAL METAPLASTIC MUCOSA AND EXHIBIT STRUCTURAL ALTERATIONS OF TUMOR SUPPRESSOR GENES, ESPECIALLY P53. THEY APPEAR TO BE RELATED TO CHRONIC INJURY, PERHAPS DUE TO HELICOBACTER PYLORI INFECTION. APPROXIMATELY 20% OF DIFFERENTIATED CARCINOMAS (ORDINARY-TYPE) HAVE EVIDENCE OF MUTATOR PATHWAY TUMORIGENESIS. MUTATIONS OF E-CADHERIN ARE MAINLY INVOLVED IN THE PROGRESSION OF DIFFERENTIATED CARCINOMAS TO UNDIFFERENTIATED TUMORS. THE MOLECULAR PATHWAYS OF GASTRIC CARCINOGENESIS DEPEND ON THE HISTOLOGICAL BACKGROUND, AND GASTRIC CARCINOMAS SHOW DISTINCT BIOLOGICAL BEHAVIORS AS A RESULT OF DISCERNIBLE CELLULAR GENETIC AND EPIGENETIC ALTERATIONS. 2002 18 3439 27 HYPERMETHYLATION AND LOSS OF EXPRESSION OF GLUTATHIONE PEROXIDASE-3 IN BARRETT'S TUMORIGENESIS. CHRONIC GASTROESOPHAGEAL REFLUX DISEASE IS A KNOWN RISK FACTOR FOR BARRETT'S ESOPHAGUS (BE), WHICH INDUCES OXIDATIVE MUCOSAL DAMAGE. GLUTATHIONE PEROXIDASE-3 (GPX3) IS A SECRETORY PROTEIN WITH POTENT EXTRACELLULAR ANTIOXIDANT ACTIVITY. IN THIS STUDY, WE HAVE INVESTIGATED THE MRNA AND PROTEIN EXPRESSION OF GPX3, AND EXPLORED PROMOTER HYPERMETHYLATION AS AN EPIGENETIC MECHANISM FOR GPX3 GENE INACTIVATION DURING BARRETT'S CARCINOGENESIS. QUANTITATIVE REAL-TIME REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION ON 42 BARRETT'S ADENOCARCINOMAS (BAS) REVEALED CONSISTENTLY REDUCED LEVELS OF GPX3 MRNA IN 91% OF TUMOR SAMPLES. GPX3 PROMOTER HYPERMETHYLATION WAS DETECTED IN 62% OF BARRETT'S METAPLASIA, 82% OF DYSPLASIA, AND 88% OF BA SAMPLES. HYPERMETHYLATION OF BOTH ALLELES OF GPX3 WAS MOST FREQUENTLY SEEN IN BAS (P = .001). IMMUNOHISTOCHEMICAL STAINING OF GPX3 IN MATCHING TISSUE SECTIONS (NORMAL, BE, BARRETT'S DYSPLASIA, AND BA) REVEALED STRONG IMMUNOSTAINING FOR GPX3 IN NORMAL ESOPHAGEAL AND GASTRIC TISSUES. HOWEVER, WEAK TO ABSENT GPX3 STAINING WAS OBSERVED IN BARRETT'S DYSPLASIA AND ADENOCARCINOMA SAMPLES WHERE THE PROMOTER WAS HYPERMETHYLATED. THE DEGREE OF LOSS OF IMMUNOHISTOCHEMISTRY CORRELATED WITH THE HYPERMETHYLATION PATTERN (MONOALLELIC VERSUS BIALLELIC). THE OBSERVED HIGH FREQUENCY OF PROMOTER HYPERMETHYLATION AND PROGRESSIVE LOSS OF GPX3 EXPRESSION IN BA AND ITS ASSOCIATED LESIONS, TOGETHER WITH ITS KNOWN FUNCTION AS A POTENT ANTIOXIDANT, SUGGEST THAT EPIGENETIC INACTIVATION AND REGULATION OF GLUTATHIONE PATHWAY MAY BE CRITICAL IN THE DEVELOPMENT AND PROGRESSION OF BE. 2005 19 196 24 ACID REFLUX AND OESOPHAGEAL CANCER. BARRETT'S METAPLASIA IS ONE OF THE COMMONEST PREMALIGNANT LESIONS IN THE WESTERN WORLD FOLLOWING COLORECTAL ADENOMAS. ONE IN 50 OF THE ADULT POPULATION DEVELOPS BARRETT'S AS A CONSEQUENCE OF CHRONIC GASTRO-OESOPHAGEAL REFLUX. THE MUCOSAL INFLAMMATION SEEN WITHIN PATIENTS WITH GASTRO-OESOPHAGEAL REFLUX SEEMS LIKELY TO DRIVE THE GROWTH OF THE METAPLASTIC MUCOSA AND ALSO HELP DIRECT FURTHER ONCOLOGICAL CHANGE, YET THE MOLECULAR EVENTS THAT CHARACTERIZE THE PATHWAY FROM INFLAMMATION TO METAPLASIA TO DYSPLASIA AND ADENOCARCINOMA ARE POORLY UNDERSTOOD. THERE IS HOPE THAT UNDERSTANDING THE ROLE OF OESOPHAGEAL INFLAMMATION WILL PROVIDE IMPORTANT INSIGHT INTO THE DEVELOPMENT OF BARRETT'S METAPLASIA AND OESOPHAGEAL CANCER. THIS CHAPTER WILL DISCUSS THE INFLAMMATION SEEN WITHIN CONTEXT OF BARRETT'S OESOPHAGUS AND ALSO CLINICAL TRIALS WHICH HOPE TO ADDRESS THIS COMMON PREMALIGNANT DISEASE. THERE ARE SEVERAL ONGOING CLINICAL TRIALS WHICH ARE AIMING TO PROVIDE DATA USING ANTI-INFLAMMATORY THERAPIES TO TACKLE THIS IMPORTANT PREMALIGNANT CONDITION. THERE IS NEW DATA PRESENTED WHICH SUGGESTS THAT DATA FROM THE ASPIRIN ESOMEPRAZOLE CHEMOPREVENTION TRIAL (ASPECT) MAY HOLD THE CLUE TO DISEASE TREATMENT AND THAT THE CYTOKINE TNF-ALPHA SEEMS TO BE A KEY SIGNALLING MOLECULE IN THE METAPLASIA-DYSPLASIA-CARCINOMA SEQUENCE. SPECIFICALLY IT APPEARS THAT BOTH EPIGENETIC AND INHERITED GENETICS COOPERATE TO MODULATE THE PROGNOSIS. 2011 20 5628 14 SEMEN ABNORMALITIES, SPERM DNA DAMAGE AND GLOBAL HYPERMETHYLATION IN HEALTH WORKERS OCCUPATIONALLY EXPOSED TO IONIZING RADIATION. BACKGROUND: CYTOGENETIC STUDIES HAVE DEMONSTRATED THAT LOW LEVELS OF CHRONIC RADIATION EXPOSURE CAN POTENTIALLY INCREASE THE FREQUENCY OF CHROMOSOMAL ABERRATIONS AND ANEUPLOIDY IN SOMATIC CELLS. EPIDEMIOLOGICAL STUDIES HAVE SHOWN THAT HEALTH WORKERS OCCUPATIONALLY EXPOSED TO IONIZING RADIATION BEAR AN INCREASED RISK OF HEMATOLOGICAL MALIGNANCIES. OBJECTIVES: TO FIND THE INFLUENCE OF OCCUPATIONAL RADIATION EXPOSURE ON SEMEN CHARACTERISTICS, INCLUDING GENETIC AND EPIGENETIC INTEGRITY OF SPERMATOZOA IN A CHRONICALLY EXPOSED POPULATION. METHODS: THIS CROSS SECTIONAL STUDY INCLUDED 134 MALE VOLUNTEERS OF WHICH 83 WERE OCCUPATIONALLY EXPOSED TO IONIZING RADIATION AND 51 WERE NON-EXPOSED CONTROL SUBJECTS. SEMEN CHARACTERISTICS, SPERM DNA FRAGMENTATION, ANEUPLOIDY AND INCIDENCE OF GLOBAL HYPERMETHYLATION IN THE SPERMATOZOA WERE DETERMINED AND COMPARED BETWEEN THE NON-EXPOSED AND THE EXPOSED GROUP. RESULTS: DIRECT COMPARISON OF THE SEMEN CHARACTERISTICS BETWEEN THE NON-EXPOSED AND THE EXPOSED POPULATION REVEALED SIGNIFICANT DIFFERENCES IN MOTILITY CHARACTERISTICS, VIABILITY, AND MORPHOLOGICAL ABNORMALITIES (P<0.05-0.0001). ALTHOUGH, THE LEVEL OF SPERM DNA FRAGMENTATION WAS SIGNIFICANTLY HIGHER IN THE EXPOSED GROUP AS COMPARED TO THE NON-EXPOSED GROUP (P<0.05-0.0001), THE INCIDENCE OF SPERM ANEUPLOIDY WAS NOT STATISTICALLY DIFFERENT BETWEEN THE TWO GROUPS. HOWEVER, A SIGNIFICANT NUMBER OF HYPERMETHYLATED SPERMATOZOA WERE OBSERVED IN THE EXPOSED GROUP IN COMPARISON TO NON-EXPOSED GROUP (P<0.05). CONCLUSIONS: WE PROVIDE THE FIRST EVIDENCE ON THE DETRIMENTAL EFFECTS OF OCCUPATIONAL RADIATION EXPOSURE ON FUNCTIONAL, GENETIC AND EPIGENETIC INTEGRITY OF SPERM IN HEALTH WORKERS. HOWEVER, FURTHER STUDIES ARE REQUIRED TO CONFIRM THE POTENTIAL DETRIMENTAL EFFECTS OF IONIZING RADIATION IN THESE SUBJECTS. 2013