1 3671 192 INFLAMMATION AND CANCER. INFECTION AND INFLAMMATION ACCOUNT FOR APPROXIMATELY 25% OF CANCER-CAUSING FACTORS. INFLAMMATION-RELATED CANCERS ARE CHARACTERIZED BY MUTAGENIC DNA LESIONS, SUCH AS 8-OXO-7,8-DIHYDRO-2'-DEOXYGUANOSINE (8-OXODG) AND 8-NITROGUANINE. OUR PREVIOUS STUDIES DEMONSTRATED THE FORMATION OF 8-OXODG AND 8-NITROGUANINE IN THE TISSUES OF CANCER AND PRECANCEROUS LESIONS DUE TO INFECTION (E.G., OPISTHORCHIS VIVERRINI-RELATED CHOLANGIOCARCINOMA, SCHISTOSOMA HAEMATOBIUM-ASSOCIATED BLADDER CANCER, HELICOBACTER PYLORI-INFECTED GASTRIC CANCER, HUMAN PAPILLOMAVIRUS-RELATED CERVICAL CANCER, EPSTEIN-BARR VIRUS-INFECTED NASOPHARYNGEAL CARCINOMA) AND PRO-INFLAMMATORY FACTORS (E.G., ASBESTOS, NANOMATERIALS, AND INFLAMMATORY DISEASES SUCH AS BARRETT'S ESOPHAGUS AND ORAL LEUKOPLAKIA). INTERESTINGLY, SEVERAL OF OUR STUDIES SUGGESTED THAT INFLAMMATION-ASSOCIATED DNA DAMAGE IN CANCER STEM-LIKE CELLS LEADS TO CANCER DEVELOPMENT WITH AGGRESSIVE CLINICAL FEATURES. REACTIVE OXYGEN/NITROGEN SPECIES FROM INFLAMMATION DAMAGE NOT ONLY DNA BUT ALSO OTHER BIOMACROMOLECULES, SUCH AS PROTEINS AND LIPIDS, RESULTING IN THEIR DYSFUNCTION. WE IDENTIFIED OXIDATIVELY DAMAGED PROTEINS IN CANCER TISSUES BY 2D OXYBLOT FOLLOWED BY MALDI-TOF/TOF. AS AN EXAMPLE, OXIDATIVELY DAMAGED TRANSFERRIN RELEASED IRON ION, WHICH MAY MEDIATE FENTON REACTIONS AND GENERATE ADDITIONAL REACTIVE OXYGEN SPECIES. DYSFUNCTION OF ANTI-OXIDATIVE PROTEINS DUE TO THIS DAMAGE MIGHT INCREASE OXIDATIVE STRESS. SUCH DAMAGE IN BIOMACROMOLECULES MAY FORM A VICIOUS CYCLE OF OXIDATIVE STRESS, LEADING TO CANCER DEVELOPMENT. EPIGENETIC ALTERATIONS SUCH AS DNA METHYLATION AND MICRORNA DYSREGULATION PLAY VITAL ROLES IN CARCINOGENESIS, ESPECIALLY IN INFLAMMATION-RELATED CANCERS. WE EXAMINED EPIGENETIC ALTERATIONS, DNA METHYLATION AND MICRORNA DYSREGULATION, IN EPSTEIN-BARR VIRUS-RELATED NASOPHARYNGEAL CARCINOMA IN THE ENDEMIC AREA OF SOUTHERN CHINA AND FOUND SEVERAL DIFFERENTIALLY METHYLATED TUMOR SUPPRESSOR GENE CANDIDATES BY USING A NEXT-GENERATION SEQUENCER. AMONG THESE CANDIDATES, WE REVEALED HIGHER METHYLATION RATES OF RAS-LIKE ESTROGEN-REGULATED GROWTH INHIBITOR (RERG) IN BIOPSY SPECIMENS OF NASOPHARYNGEAL CARCINOMA MORE CONVENIENTLY BY USING RESTRICTION ENZYME-BASED REAL-TIME PCR. THIS RESULT MAY HELP TO IMPROVE CANCER SCREENING STRATEGIES. WE PROFILED MICRORNAS OF NASOPHARYNGEAL CARCINOMA TISSUES USING MICROARRAYS. QUANTITATIVE RT-PCR ANALYSIS CONFIRMED THE CONCORDANT DOWNREGULATION OF MIR-497 IN CANCER TISSUES AND PLASMA, SUGGESTING THAT PLASMA MIR-497 COULD BE USED AS A DIAGNOSTIC BIOMARKER FOR NASOPHARYNGEAL CARCINOMA. CHRONIC INFLAMMATION PROMOTES GENETIC AND EPIGENETIC ABERRATIONS, WITH VARIOUS PATHOGENESES. THESE CHANGES MAY BE USEFUL BIOMARKERS IN LIQUID BIOPSY FOR EARLY DETECTION AND PREVENTION OF CANCER. 2018 2 5582 54 ROLE OF NITRATIVE AND OXIDATIVE DNA DAMAGE IN INFLAMMATION-RELATED CARCINOGENESIS. CHRONIC INFLAMMATION INDUCED BY BIOLOGICAL, CHEMICAL, AND PHYSICAL FACTORS HAS BEEN FOUND TO BE ASSOCIATED WITH THE INCREASED RISK OF CANCER IN VARIOUS ORGANS. WE REVEALED THAT INFECTIOUS AGENTS INCLUDING LIVER FLUKE, HELICOBACTER PYLORI, AND HUMAN PAPILLOMA VIRUS AND NONINFECTIOUS AGENTS SUCH AS ASBESTOS FIBER INDUCED INOS-DEPENDENT FORMATION OF 8-NITROGUANINE AND 8-OXO-7, 8-DIHYDRO-2'-DEOXYGUANOSINE (8-OXODG) IN CANCER TISSUES AND PRECANCEROUS REGIONS. OUR RESULTS WITH THE COLOCALIZATION OF PHOSPHORYLATED ATM AND GAMMA-H2AX WITH 8-OXODG AND 8-NITROGUANINE IN INFLAMMATION-RELATED CANCER TISSUES SUGGEST THAT DNA BASE DAMAGE LEADS TO DOUBLE-STRANDED BREAKS. IT IS INTERESTING FROM THE ASPECT OF GENETIC INSTABILITY. WE ALSO DEMONSTRATED IL-6-MODULATED INOS EXPRESSION VIA STAT3 AND EGFR IN EPSTEIN-BARR-VIRUS-ASSOCIATED NASOPHARYNGEAL CARCINOMA AND FOUND PROMOTER HYPERMETHYLATION IN SEVERAL TUMOR SUPPRESSOR GENES. SUCH EPIGENETIC ALTERATION MAY OCCUR BY CONTROLLING THE DNA METHYLATION THROUGH IL-6-MEDIATED JAK/STAT3 PATHWAYS. COLLECTIVELY, 8-NITROGUANINE WOULD BE A USEFUL BIOMARKER FOR PREDICTING THE RISK OF INFLAMMATION-RELATED CANCERS. 2012 3 2122 46 EPIGENETIC IMPACT OF INFECTION ON CARCINOGENESIS: MECHANISMS AND APPLICATIONS. VIRAL AND BACTERIAL INFECTIONS ARE INVOLVED IN THE DEVELOPMENT OF HUMAN CANCERS, SUCH AS LIVER, NASOPHARYNGEAL, CERVICAL, HEAD AND NECK, AND GASTRIC CANCERS. ABERRANT DNA METHYLATION IS FREQUENTLY PRESENT IN THESE CANCERS, AND SOME OF THE ABERRANTLY METHYLATED GENES ARE CAUSALLY INVOLVED IN CANCER DEVELOPMENT AND PROGRESSION. NOTABLY, ABERRANT DNA METHYLATION CAN BE PRESENT EVEN IN NON-CANCEROUS OR PRECANCEROUS TISSUES, AND ITS LEVELS CORRELATE WITH THE RISK OF CANCER DEVELOPMENT, PRODUCING A SO-CALLED 'EPIGENETIC FIELD FOR CANCERIZATION'. MECHANISTICALLY, MOST VIRAL OR BACTERIAL INFECTIONS INDUCE DNA METHYLATION INDIRECTLY VIA CHRONIC INFLAMMATION, BUT RECENT STUDIES HAVE INDICATED THAT SOME VIRUSES HAVE DIRECT EFFECTS ON THE EPIGENETIC MACHINERY OF HOST CELLS. FROM A TRANSLATIONAL VIEWPOINT, A RECENT MULTICENTER PROSPECTIVE COHORT STUDY DEMONSTRATED THAT ASSESSMENT OF THE EXTENT OF ALTERATIONS IN DNA METHYLATION IN NON-CANCEROUS TISSUES CAN BE USED TO PREDICT CANCER RISK. FURTHERMORE, SUPPRESSION OF ABERRANT DNA METHYLATION WAS SHOWN TO BE A USEFUL STRATEGY FOR CANCER PREVENTION IN AN ANIMAL MODEL. HERE, WE REVIEW THE INVOLVEMENT OF ABERRANT DNA METHYLATION IN VARIOUS TYPES OF INFECTION-ASSOCIATED CANCERS, ALONG WITH INDIVIDUAL INDUCTION MECHANISMS, AND WE DISCUSS THE APPLICATION OF THESE FINDINGS FOR CANCER PREVENTION, DIAGNOSIS, AND THERAPY. 2016 4 4114 39 MECHANISMS FOR THE INDUCTION OF GASTRIC CANCER BY HELICOBACTER PYLORI INFECTION: ABERRANT DNA METHYLATION PATHWAY. MULTIPLE PATHOGENIC MECHANISMS BY WHICH HELICOBACTER PYLORI INFECTION INDUCES GASTRIC CANCER HAVE BEEN ESTABLISHED IN THE LAST TWO DECADES. IN PARTICULAR, ABERRANT DNA METHYLATION IS INDUCED IN MULTIPLE DRIVER GENES, WHICH INACTIVATES THEM. METHYLATION PROFILES IN GASTRIC CANCER ARE ASSOCIATED WITH SPECIFIC SUBTYPES, SUCH AS MICROSATELLITE INSTABILITY. RECENT COMPREHENSIVE AND INTEGRATED ANALYSES SHOWED THAT MANY CANCER-RELATED PATHWAYS ARE MORE FREQUENTLY ALTERED BY ABERRANT DNA METHYLATION THAN BY MUTATIONS. ABERRANT DNA METHYLATION CAN EVEN BE PRESENT IN NONCANCEROUS GASTRIC MUCOSAE, PRODUCING AN "EPIGENETIC FIELD FOR CANCERIZATION." MECHANISTICALLY, H. PYLORI-INDUCED CHRONIC INFLAMMATION, BUT NOT H. PYLORI ITSELF, PLAYS A DIRECT ROLE IN THE INDUCTION OF ABERRANT DNA METHYLATION. THE EXPRESSION OF THREE INFLAMMATION-RELATED GENES, IL1B, NOS2, AND TNF, IS HIGHLY ASSOCIATED WITH THE INDUCTION OF ABERRANT DNA METHYLATION. IMPORTANTLY, THE DEGREE OF ACCUMULATED ABERRANT DNA METHYLATION IS STRONGLY CORRELATED WITH GASTRIC CANCER RISK. A RECENT MULTICENTER PROSPECTIVE COHORT STUDY DEMONSTRATED THE UTILITY OF EPIGENETIC CANCER RISK DIAGNOSIS FOR METACHRONOUS GASTRIC CANCER. SUPPRESSION OF ABERRANT DNA METHYLATION BY A DEMETHYLATING AGENT WAS SHOWN TO INHIBIT GASTRIC CANCER DEVELOPMENT IN AN ANIMAL MODEL. INDUCTION OF ABERRANT DNA METHYLATION IS THE MAJOR PATHWAY BY WHICH H. PYLORI INFECTION INDUCES GASTRIC CANCER, AND THIS CAN BE UTILIZED FOR TRANSLATIONAL OPPORTUNITIES. 2017 5 2994 43 GENETIC PATHOGENESIS OF INFLAMMATION-ASSOCIATED CANCERS IN DIGESTIVE ORGANS. EPIDEMIOLOGICAL, CLINICAL, AND BIOLOGICAL STUDIES CONVINCINGLY DEMONSTRATE THAT CHRONIC INFLAMMATION PREDISPOSES TO THE DEVELOPMENT OF HUMAN CANCERS. IN DIGESTIVE ORGANS, INFLAMMATION-ASSOCIATED CANCERS INCLUDE COLITIS-ASSOCIATED COLORECTAL CANCERS, HELICOBACTER PYLORI-ASSOCIATED GASTRIC CANCER, AS WELL AS BARRETT'S ESOPHAGUS AND ESOPHAGEAL ADENOCARCINOMA ASSOCIATED WITH CHRONIC DUODENOGASTRIC-ESOPHAGEAL REFLUX. CANCER IS A GENOMIC DISEASE, AND STEPWISE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS OF TUMOR-RELATED GENES LEADS TO THE DEVELOPMENT OF TUMOR CELLS. RECENT GENOME ANALYSES SHOW THAT GENETIC ALTERATIONS, WHICH ARE EVOKED BY INFLAMMATION, ARE LATENTLY ACCUMULATED IN INFLAMED EPITHELIAL CELLS OF DIGESTIVE ORGANS. PRODUCTION OF REACTIVE OXYGEN AND ABERRANT EXPRESSION OF ACTIVATION-INDUCED CYTIDINE DEAMINASE, A NUCLEOTIDE-EDITING ENZYME, COULD BE INDUCED IN INFLAMED GASTROINTESTINAL EPITHELIAL CELLS AND PLAY A ROLE AS A GENOMIC MODULATOR OF INFLAMMATION-ASSOCIATED CARCINOGENESIS. UNDERSTANDING THE MOLECULAR LINKAGE BETWEEN INFLAMMATION AND GENETIC ALTERATIONS WILL OPEN UP A NEW FIELD OF TUMOR BIOLOGY AND PROVIDE A NOVEL STRATEGY FOR THE PREVENTION OF INFLAMMATION-ASSOCIATED TUMORIGENESIS. 2021 6 342 49 ALTERATIONS OF DNA METHYLATION ASSOCIATED WITH ABNORMALITIES OF DNA METHYLTRANSFERASES IN HUMAN CANCERS DURING TRANSITION FROM A PRECANCEROUS TO A MALIGNANT STATE. ALTERATIONS OF DNA METHYLATION ARE ONE OF THE MOST CONSISTENT EPIGENETIC CHANGES IN HUMAN CANCERS. HUMAN CANCERS GENERALLY SHOW GLOBAL DNA HYPOMETHYLATION ACCOMPANIED BY REGION-SPECIFIC HYPERMETHYLATION. ALTERATIONS OF DNA METHYLATION MAY RESULT IN CHROMOSOMAL INSTABILITY AS A RESULT OF CHANGES IN CHROMATIN STRUCTURE. DNA HYPERMETHYLATION OF CPG ISLANDS SILENCES VARIOUS TUMOR-RELATED GENES. ALTERATIONS OF DNA METHYLATION ARE FREQUENTLY OBSERVED IN CANCERS ASSOCIATED WITH CHRONIC INFLAMMATION AND/OR PERSISTENT INFECTION WITH VIRUSES OR OTHER PATHOGENIC MICROORGANISMS, SUCH AS HEPATITIS B OR C VIRUSES, EPSTEIN-BARR VIRUS, HUMAN PAPILLOMAVIRUS AND HELICOBACTER PYLORI, OR WITH CIGARETTE SMOKING. ACCUMULATING EVIDENCE SUGGESTS THAT ALTERATIONS OF DNA METHYLATION ARE INVOLVED EVEN IN THE EARLY AND PRECANCEROUS STAGES. ON THE OTHER HAND, IN PATIENTS WITH CANCERS, ABERRANT DNA METHYLATION IS SIGNIFICANTLY ASSOCIATED WITH POORER TUMOR DIFFERENTIATION, TUMOR AGGRESSIVENESS AND POOR PROGNOSIS. PRECANCEROUS CONDITIONS SHOWING ALTERATIONS OF DNA METHYLATION MAY PROGRESS RAPIDLY AND GENERATE MORE MALIGNANT CANCERS. DNA METHYLTRANSFERASE (DNMT) 1 OVER-EXPRESSION IS NOT A SECONDARY RESULT OF INCREASED CELL PROLIFERATIVE ACTIVITY BUT IS SIGNIFICANTLY CORRELATED WITH THE CPG ISLAND METHYLATOR PHENOTYPE, WHICH IS DEFINED AS FREQUENT DNA HYPERMETHYLATION OF C-TYPE CPG ISLANDS THAT ARE USUALLY METHYLATED IN A CANCER-SPECIFIC (NOT AGE-DEPENDENT) MANNER. SPLICING ALTERATION OF DNMT3B MAY RESULT IN CHROMOSOMAL INSTABILITY THROUGH DNA HYPOMETHYLATION OF PERICENTROMERIC SATELLITE REGIONS. ALTERATION OF DNA METHYLATION MAY BECOME AN INDICATOR FOR CARCINOGENETIC RISK ESTIMATION AND EARLY DIAGNOSIS OF CANCERS AND A BIOLOGICAL PREDICTOR OF POOR PROGNOSIS IN PATIENTS WITH CANCERS. CORRECTION OF DNA METHYLATION STATUS MAY OFFER A NEW STRATEGY FOR PREVENTION AND THERAPY OF CANCERS. 2007 7 5276 48 PROMOTER METHYLATION OF TUMOR-RELATED GENES IN GASTRIC CARCINOGENESIS. ABERRANT PROMOTER METHYLATION AND SUBSEQUENT SILENCING OF CANCER-RELATED GENES HAS BEEN RECOGNIZED AS AN IMPORTANT PATHWAY INVOLVED IN GASTRIC CARCINOGENESIS. IN FACT, SEVERAL FACTORS ARE BELIEVED TO CONTRIBUTE TO ITS INDUCTION IN GASTRIC EPITHELIA, INCLUDING AGING, DIET, CHRONIC INFLAMMATION AND INFECTION OF HELICOBACTER PYLORI (H. PYLORI) AND EPSTEIN-BARR VIRUS (EBV). HOWEVER, THE UNDERLING MECHANISMS ARE NOT COMPLETELY IDENTIFIED, DESPITE THE BELIEF THAT INCREASED EXPRESSION OR ACTIVITY OF DNA METHYLTRANSFERASES (DNMTS), OR DECREASED DEMETHYLATION ACTIVITY MAY CONTRIBUTE TO THE EXCESSIVE METHYLATION. A GREAT NUMBER OF GENES WITH PROMOTER METHYLATION HAVE BEEN OBSERVED IN GASTRIC CANCER (GC), AMONG WHICH P16INK4A (P16), MUT L HOMOLOGUE 1 (MLH1), EPITHELIAL-CADHERIN (E-CADHERIN), RUNT-RELATED TRANSCRIPTION FACTOR 3 (RUNX3), ADENOMATOUS POLYPOSIS COLI (APC), O(6)-METHYLGUANINE-DNA METHYLTRANSFERASE (MGMT), RAS ASSOCIATION DOMAIN FAMILY 1A (RASSF1A) AND DEATH-ASSOCIATED PROTEIN KINASE (DAPK) HAVE BEEN EXTENSIVELY STUDIED. UNLIKE THE DISTINCT METHYLATION CHARACTERIZATION IN SINGLE GENES, METHYLATION ANALYSIS OF MULTIPLE GENES MAY PROVIDE MORE INFORMATION IN RISK PREDICTION, EARLY DETECTION, PROGNOSIS ASSESSMENT AND CHEMOTHERAPY CHOICE FOR GC. SPECIFICALLY, PARTICULAR MONITORING AND SCREENING SHOULD BE PERFORMED ON THOSE OVER 45 YEARS OLD, WITH PRECANCEROUS GASTRIC DISEASE OR INFECTION OF H. PYLORI OR EBV. AS AN ALTERNATIVE TO TUMOR TISSUES, METHYLATION DETECTION IN PATIENT SERA OR GASTRIC WASHES MAY ALSO BE USED IN RISK PREDICTION AND EARLY DETECTION. HOWEVER, WHAT STILL POSES A GREAT CHALLENGE AS WELL AS A PUZZLE IS THE DETERMINATION OF THE VERY GENES THAT SHOULD BE USED IN METHYLATION ANALYSIS. BECAUSE EPIGENETIC ALTERATIONS ARE NORMALLY REVERSIBLE, DRUGS OR CHEMICAL COMPOUNDS WITH DEMETHYLATING ACTIVITY, SUCH AS 5-AZA-2'-DEOXYCYTIDINE (5-AZA-DC) COULD BE USED IN THE TREATMENT OF PATIENTS WITH MULTIPLE GENE METHYLATION. IN VIEW OF THE ADVERSE EFFECTS OF 5-AZA-DC, DNMT-TARGETED STRATEGY HAS BEEN PROPOSED AND MAY PROVE TO BE MORE EFFECTIVE THAN DEMETHYLATING AGENTS. 2012 8 4539 36 MULTISTAGE CARCINOGENESIS IN MOUSE SKIN. THE MOUSE SKIN MODEL OF MULTISTAGE CARCINOGENESIS HAS FOR MANY YEARS PROVIDED A CONCEPTUAL FRAMEWORK FOR STUDYING CARCINOGENESIS MECHANISMS AND POTENTIAL MEANS FOR INHIBITING SPECIFIC STAGES OF CARCINOGENESIS. THE PROCESS OF SKIN CARCINOGENESIS INVOLVES THE STEPWISE ACCUMULATION OF GENETIC CHANGE ULTIMATELY LEADING TO MALIGNANCY. INITIATION, THE FIRST STEP IN MULTISTAGE SKIN CARCINOGENESIS INVOLVES CARCINOGEN-INDUCED GENETIC CHANGES. A TARGET GENE IDENTIFIED FOR SOME SKIN TUMOR INITIATORS IS C-HA-RAS. THE SECOND STEP, THE PROMOTION STAGE, INVOLVES PROCESSES WHEREBY INITIATED CELLS UNDERGO SELECTIVE CLONAL EXPANSION TO FORM VISIBLE PREMALIGNANT LESIONS TERMED PAPILLOMAS. THE PROCESS OF TUMOR PROMOTION INVOLVES THE PRODUCTION AND MAINTENANCE OF A SPECIFIC AND CHRONIC HYPERPLASIA CHARACTERIZED BY A SUSTAINED CELLULAR PROLIFERATION OF EPIDERMAL CELLS. THESE CHANGES ARE BELIEVED TO RESULT FROM EPIGENETIC MECHANISMS SUCH AS ACTIVATION OF THE CELLULAR RECEPTOR, PROTEIN KINASE C, BY SOME CLASSES OF TUMOR PROMOTERS. THE PROGRESSION STAGE INVOLVES THE CONVERSION OF PAPILLOMAS TO MALIGNANT TUMORS, SQUAMOUS CELL CARCINOMAS. THE ACCUMULATION OF ADDITIONAL GENETIC CHANGES IN CELLS COMPRISING PAPILLOMAS HAS BEEN CORRELATED WITH TUMOR PROGRESSION, INCLUDING TRISOMIES OF CHROMOSOMES 6 AND 7 AND LOSS OF HETEROZYGOSITY. THE CURRENT REVIEW FOCUSES ON THE MECHANISMS INVOLVED IN MULTISTAGE SKIN CARCINOGENESIS, A SUMMARY OF KNOWN INHIBITORS OF SPECIFIC STAGES AND THEIR PROPOSED MECHANISMS OF ACTION, AND THE RELEVANCE OF THIS MODEL SYSTEM TO HUMAN CANCER. 1992 9 3067 47 GENOME-WIDE DNA METHYLATION PROFILES IN PRECANCEROUS CONDITIONS AND CANCERS. ALTERATIONS OF DNA METHYLATION, WHICH RESULT IN CHROMOSOMAL INSTABILITY AND SILENCING OF TUMOR-RELATED GENES, ARE AMONG THE MOST CONSISTENT EPIGENETIC CHANGES OBSERVED IN HUMAN CANCERS. ANALYSIS OF TISSUE SPECIMENS HAS REVEALED THAT DNA METHYLATION ALTERATIONS PARTICIPATE IN MULTISTAGE CARCINOGENESIS, EVEN FROM THE EARLY AND PRECANCEROUS STAGES, ESPECIALLY IN ASSOCIATION WITH CHRONIC INFLAMMATION AND/OR PERSISTENT VIRAL INFECTION, SUCH AS CHRONIC HEPATITIS OR LIVER CIRRHOSIS RESULTING FROM INFECTION WITH HEPATITIS B OR C VIRUS. DNA METHYLATION ALTERATIONS CAN ACCOUNT FOR THE HISTOLOGICAL HETEROGENEITY AND CLINICOPATHOLOGICAL DIVERSITY OF HUMAN CANCERS. OVEREXPRESSION OF DNA METHYLTRANSFERASE 1 IS NOT A SECONDARY RESULT OF INCREASED CELL PROLIFERATIVE ACTIVITY, BUT IS SIGNIFICANTLY CORRELATED WITH ACCUMULATION OF DNA HYPERMETHYLATION IN CPG ISLANDS OF TUMOR-RELATED GENES. ALTERATION OF DNA METHYLTRANSFERASE 3B SPLICING MAY RESULT IN CHROMOSOMAL INSTABILITY THROUGH DNA HYPOMETHYLATION IN PERICENTROMERIC SATELLITE REGIONS. GENOME-WIDE ANALYSIS OF DNA METHYLATION STATUS HAS REVEALED THAT THE DNA METHYLATION PROFILE AT THE PRECANCEROUS STAGE IS BASICALLY INHERITED BY THE CORRESPONDING CANCERS DEVELOPING IN INDIVIDUAL PATIENTS. DNA METHYLATION STATUS IS NOT SIMPLY ALTERED AT THE PRECANCEROUS STAGE; RATHER, DNA METHYLATION ALTERATIONS AT THE PRECANCEROUS STAGE MAY CONFER VULNERABILITY TO FURTHER GENETIC AND EPIGENETIC ALTERATIONS, GENERATE MORE MALIGNANT CANCERS, AND THUS DETERMINE PATIENT OUTCOME. THEREFORE, GENOME-WIDE DNA METHYLATION PROFILING MAY PROVIDE OPTIMAL INDICATORS FOR CARCINOGENETIC RISK ESTIMATION AND PROGNOSTICATION, AND THUS PROVIDE AN AVENUE FOR CANCER PREVENTION AND THERAPY ON AN INDIVIDUAL BASIS. 2010 10 3659 44 INDUCTION OF EPIGENETIC ALTERATIONS BY CHRONIC INFLAMMATION AND ITS SIGNIFICANCE ON CARCINOGENESIS. CHRONIC INFLAMMATION IS DEEPLY INVOLVED IN DEVELOPMENT OF HUMAN CANCERS, SUCH AS GASTRIC AND LIVER CANCERS. INDUCTION OF CELL PROLIFERATION, PRODUCTION OF REACTIVE OXYGEN SPECIES, AND DIRECT STIMULATION OF EPITHELIAL CELLS BY INFLAMMATION-INDUCING FACTORS HAVE BEEN CONSIDERED AS MECHANISMS INVOLVED. INFLAMMATION-RELATED CANCERS ARE KNOWN FOR THEIR MULTIPLE OCCURRENCES, AND ABERRANT DNA METHYLATION IS KNOWN TO BE PRESENT EVEN IN NONCANCEROUS TISSUES. IMPORTANTLY, FOR SOME CANCERS, THE DEGREE OF ACCUMULATION HAS BEEN DEMONSTRATED TO BE CORRELATED WITH RISK OF DEVELOPING CANCERS. THIS INDICATES THAT INFLAMMATION INDUCES ABERRANT EPIGENETIC ALTERATIONS IN A TISSUE EARLY IN THE PROCESS OF CARCINOGENESIS, AND ACCUMULATION OF SUCH ALTERATIONS FORMS "AN EPIGENETIC FIELD FOR CANCERIZATION." THIS ALSO SUGGESTS THAT INHIBITION OF INDUCTION OF EPIGENETIC ALTERATIONS AND REMOVAL OF THE ACCUMULATED ALTERATIONS ARE NOVEL APPROACHES TO CANCER PREVENTION. DISTURBANCES IN CYTOKINE AND CHEMOKINE SIGNALS AND INDUCTION OF CELL PROLIFERATIONS ARE IMPORTANT MECHANISMS OF HOW INFLAMMATION INDUCES ABERRANT DNA METHYLATION. ABERRANT DNA METHYLATION IS INDUCED IN SPECIFIC GENES, AND GENE EXPRESSION LEVELS, THE PRESENCE OF RNA POLYMERASE II (ACTIVE OR STALLED), AND TRIMETHYLATION OF H3K4 ARE INVOLVED IN THE SPECIFICITY. EXPRESSION OF DNA METHYLTRANSFERASES (DNMTS) IS NOT NECESSARILY INDUCED BY INFLAMMATION, AND LOCAL IMBALANCE BETWEEN DNMTS AND FACTORS THAT PROTECT GENES FROM DNA METHYLATION SEEMS TO BE IMPORTANT. 2010 11 4994 36 PERFORMANCE OF DNA METHYLATION ON THE MOLECULAR PATHOGENESIS OF HELICOBACTER PYLORI IN GASTRIC CANCER; TARGETED THERAPY APPROACH. GASTRIC CANCER (GC) IS A SIGNIFICANT CAUSE OF CANCER MORTALITY WHICH HAS LED TO FOCUSED EXPLORATION OF THE PATHOLOGY OF GC. THE ADVENT OF GENOME-WIDE ANALYSIS METHODS HAS MADE IT POSSIBLE TO UNCOVER GENETIC AND EPIGENETIC FLUCTUATION SUCH AS ABNORMAL DNA METHYLATION IN GENE PROMOTER REGIONS THAT IS EXPECTED TO PLAY A KEY ROLE IN GC. THE STUDY OF GASTRIC MALIGNANCIES REQUIRES AN ETIOLOGICAL PERSPECTIVE, AND HELICOBACTER PYLORI (H. PYLORI) WAS IDENTIFIED TO PLAY A ROLE IN GC. H. PYLORI INFECTION CAUSES CHRONIC INFLAMMATION OF THE GASTRIC EPITHELIUM CAUSING ABNORMAL POLYCLONAL METHYLATION, WHICH MIGHT RAISE THE RISK OF GC. IN THE LAST TWO DECADES, VARIOUS PATHOGENIC FACTORS BY WHICH H. PYLORI INFECTION CAUSES GC HAVE BEEN DISCOVERED. ABNORMAL DNA METHYLATION IS TRIGGERED IN SEVERAL GENES, RENDERING THEM INACTIVE. IN GC, METHYLATION PATTERNS ARE LINKED TO CERTAIN SUBTYPES INCLUDING MICROSATELLITE INSTABILITY. MULTIPLE CANCER-RELATED PROCESSES ARE MORE USUALLY CHANGED BY ABNORMAL DNA METHYLATION THAN THROUGH MUTATIONS, ACCORDING TO CURRENT GENERAL AND COMBINED INVESTIGATIONS. FURTHERMORE, THE AMOUNT OF ACQUIRED ABNORMAL DNA METHYLATION IS HEAVILY LINKED TO THE CHANCES OF DEVELOPING GC. THEREFORE, WE INVESTIGATED ABNORMAL DNA METHYLATION IN GC AND THE LINK BETWEEN METHYLATION AND H. PYLORI INFECTION. 2022 12 3686 37 INFLAMMATION-RELATED ABERRANT PATTERNS OF DNA METHYLATION: DETECTION AND ROLE IN EPIGENETIC DEREGULATION OF CANCER CELL TRANSCRIPTOME. IT IS NOW APPARENT THAT EPIGENETIC ABNORMALITIES, IN PARTICULAR ALTERED DNA METHYLATION, PLAY A CRUCIAL ROLE IN THE DEVELOPMENT AND PROGRESSION OF HUMAN CANCERS. DNA HYPERMETHYLATION AT PROMOTER CPG ISLANDS IS NOW RECOGNIZED AS A THIRD MECHANISM BY WHICH INACTIVATION OF TUMOR SUPPRESSOR GENES OCCURS. ABERRANT CPG ISLAND HYPERMETHYLATION IS ALSO FREQUENTLY OBSERVED IN CHRONIC INFLAMMATION AND PRECANCEROUS LESIONS, WHICH SUGGESTS THAT IT IS AN EARLY EVENT IN TUMORIGENESIS THAT COULD SERVE AS A USEFUL TUMOR MARKER. A VARIETY OF SCREENING TECHNIQUES HAVE BEEN DEVELOPED FOR GENOME-WIDE SCREENING OF METHYLATION STATUS. OF THOSE, TRANSCRIPTOME ANALYSIS COUPLED WITH PHARMACOLOGICAL UNMASKING HAS EMERGED AS A POWERFUL TOOL FOR REVEALING DNA METHYLATION PATTERNS IN CANCER CELLS AND IDENTIFYING NEW TUMOR MARKER CANDIDATES. 2009 13 332 42 ALTERATION OF EPIGENETIC PROFILE IN HUMAN HEPATOCELLULAR CARCINOMA AND ITS CLINICAL IMPLICATIONS. HEPATOCELLULAR CARCINOMA (HCC) IS A COMMON CANCER WORLDWIDE AND DEVELOPS AGAINST A BACKGROUND OF CHRONIC LIVER DAMAGE. A VARIETY OF HCC-RELATED GENES ARE KNOWN TO BE ALTERED BY GENETIC AND EPIGENETIC MECHANISMS. THEREFORE, INFORMATION REGARDING ALTERATION OF THE GENETIC AND EPIGENETIC PROFILES IN HCC IS ESSENTIAL FOR UNDERSTANDING THE BIOLOGY OF THIS TYPE OF TUMOR. METHYLATION AT CPG SITES IN GENE PROMOTERS IS KNOWN TO AFFECT THE TRANSCRIPTION OF THE CORRESPONDING GENES. ABNORMAL REGIONAL HYPERMETHYLATION IS OBSERVED IN THE 5' REGION OF SEVERAL TUMOR SUPPRESSOR GENES (TSGS) IN HCC, AND THIS HYPERMETHYLATION MAY PROMOTE CARCINOGENESIS THROUGH THE TRANSCRIPTIONAL INACTIVATION OF DOWNSTREAM TSGS. THE DNA DAMAGE INDUCED BY OXIDATION IS A TRIGGER OF ABNORMAL DNA METHYLATION AND INACTIVATION OF TSGS THROUGH RECRUITMENT OF THE POLYCOMB REPRESSIVE COMPLEX TO THE PROMOTER SEQUENCE. THUS, OXIDATIVE STRESS MAY BE RESPONSIBLE FOR THE EMERGENCE OF HCC FROM CHRONIC HEPATITIS AND LIVER CIRRHOSIS THROUGH THE EPIGENETIC ALTERATION OF TSGS. THERE HAVE BEEN SEVERAL ATTEMPTS TO APPLY EPIGENETIC INFORMATION TO THE DIAGNOSIS AND TREATMENT OF HCC. THE PREDICTIVE VALUE OF SELECTED METHYLATION EVENTS ON SURVIVAL IN HCC PATIENTS HAS BEEN REPORTED, AND THE METHYLATION PROFILE OF BACKGROUND LIVER COULD BE ASSOCIATED WITH RECURRENCE-FREE SURVIVAL OF HCC PATIENTS WHO HAVE UNDERGONE HEPATECTOMY. ANOTHER STUDY DETECTED METHYLATED DNA FROM HCC CELLS IN SERUM, AND THE CIRCULATING TUMOR DNA WAS REGARDED AS A POTENTIAL TUMOR MARKER. IN ADDITION, SEVERAL TRIALS OF HCC THERAPY HAVE TARGETED THE EPIGENETIC MACHINERY AND WERE BASED UPON COMPREHENSIVE ANALYSES OF DNA METHYLATION OF THIS TYPE OF TUMOR. HERE, WE PRESENT AN OVERVIEW OF RESEARCH REGARDING DNA METHYLATION STATUS IN HUMAN HCC AND DESCRIBE THE CLINICAL APPLICATION OF EPIGENETIC INFORMATION TO HCC. 2014 14 1582 43 DNA METHYLATION PROFILES IN PRECANCEROUS TISSUE AND CANCERS: CARCINOGENETIC RISK ESTIMATION AND PROGNOSTICATION BASED ON DNA METHYLATION STATUS. ALTERATIONS IN DNA METHYLATION, WHICH ARE ASSOCIATED WITH DNA METHYLTRANSFERASE ABNORMALITIES AND RESULT IN SILENCING OF TUMOR-RELATED GENES AND CHROMOSOMAL INSTABILITY, ARE INVOLVED EVEN IN PRECANCEROUS CHANGES IN VARIOUS ORGANS. DNA METHYLATION ALTERATIONS ALSO ACCOUNT FOR THE HISTOLOGICAL HETEROGENEITY AND CLINICOPATHOLOGICAL DIVERSITY OF HUMAN CANCERS. THEREFORE, WE HAVE ANALYZED DNA METHYLATION ON A GENOME-WIDE SCALE IN CLINICAL TISSUE SAMPLES. OUR APPROACH USING THE BACTERIAL ARTIFICIAL CHROMOSOME ARRAY-BASED METHYLATED CPG ISLAND AMPLIFICATION METHOD HAS REVEALED THAT DNA METHYLATION ALTERATIONS CORRELATED WITH THE FUTURE DEVELOPMENT OF MORE MALIGNANT CANCERS ARE ALREADY ACCUMULATED AT THE PRECANCEROUS STAGE IN THE KIDNEY, LIVER AND URINARY TRACT. DNA METHYLATION PROFILES AT PRECANCEROUS STAGES ARE BASICALLY INHERITED BY THE CORRESPONDING CANCERS DEVELOPING IN INDIVIDUAL PATIENTS. SUCH DNA METHYLATION ALTERATIONS MAY CONFER VULNERABILITY TO FURTHER GENETIC AND EPIGENETIC ALTERATIONS, GENERATE MORE MALIGNANT CANCERS, AND THUS DETERMINE PATIENT OUTCOME. ON THE BASIS OF BACTERIAL ARTIFICIAL CHROMOSOME ARRAY-BASED METHYLATED CPG ISLAND AMPLIFICATION DATA, INDICATORS FOR CARCINOGENETIC RISK ESTIMATION HAVE BEEN ESTABLISHED USING LIVER TISSUE SPECIMENS FROM PATIENTS WITH HEPATITIS VIRUS INFECTION, CHRONIC HEPATITIS AND LIVER CIRRHOSIS OR HISTOLOGICALLY NORMAL UROTHELIA, AND FOR PROGNOSTICATION USING BIOPSY OR SURGICALLY RESECTED SPECIMENS FROM PATIENTS WITH RENAL CELL CARCINOMA, HEPATOCELLULAR CARCINOMA AND UROTHELIAL CARCINOMA. SUCH GENOME-WIDE DNA METHYLATION PROFILING HAS NOW FIRMLY ESTABLISHED THE CLINICAL RELEVANCE OF TRANSLATIONAL EPIGENETICS. 2010 15 3220 46 HELICOBACTER PYLORI AND MICRORNAS: RELATION WITH INNATE IMMUNITY AND PROGRESSION OF PRENEOPLASTIC CONDITIONS. THE ACCEPTED PARADIGM FOR INTESTINAL-TYPE GASTRIC CANCER PATHOGENESIS IS A MULTISTEP PROGRESSION FROM CHRONIC GASTRITIS INDUCED BY HELICOBACTER PYLORI (H. PYLORI) TO GASTRIC ATROPHY, INTESTINAL METAPLASIA, DYSPLASIA AND ULTIMATELY GASTRIC CANCER. THE GENETIC AND MOLECULAR MECHANISMS UNDERLYING DISEASE PROGRESSION ARE STILL NOT COMPLETELY UNDERSTOOD AS ONLY A FRACTION OF COLONIZED INDIVIDUALS EVER DEVELOP NEOPLASIA SUGGESTING THAT BACTERIAL, HOST AND ENVIRONMENTAL FACTORS ARE INVOLVED. MICRORNAS ARE NONCODING RNAS THAT MAY INFLUENCE H. PYLORI-RELATED PATHOLOGY THROUGH THE REGULATION OF THE TRANSCRIPTION AND EXPRESSION OF VARIOUS GENES, PLAYING AN IMPORTANT ROLE IN INFLAMMATION, CELL PROLIFERATION, APOPTOSIS AND DIFFERENTIATION. INDEED, H. PYLORI HAVE BEEN SHOWN TO MODIFY MICRORNA EXPRESSION IN THE GASTRIC MUCOSA AND MICRORNAS ARE INVOLVED IN THE IMMUNE HOST RESPONSE TO THE BACTERIA AND IN THE REGULATION OF THE INFLAMMATORY RESPONSE. MICRORNAS HAVE A KEY ROLE IN THE REGULATION OF INFLAMMATORY PATHWAYS AND H. PYLORI MAY INFLUENCE INFLAMMATION-MEDIATED GASTRIC CARCINOGENESIS POSSIBLY THROUGH DNA METHYLATION AND EPIGENETIC SILENCING OF TUMOR SUPPRESSOR MICRORNAS. FURTHERMORE, MICRORNAS INFLUENCED BY H. PYLORI ALSO HAVE BEEN FOUND TO BE INVOLVED IN CELL CYCLE REGULATION, APOPTOSIS AND EPITHELIAL-MESENCHYMAL TRANSITION. ALTOGETHER, MICRORNAS SEEM TO HAVE AN IMPORTANT ROLE IN THE PROGRESSION FROM GASTRITIS TO PRENEOPLASTIC CONDITIONS AND NEOPLASTIC LESIONS AND SINCE EACH MICRORNA CAN CONTROL THE EXPRESSION OF HUNDREDS TO THOUSANDS OF GENES, KNOWLEDGE OF MICRORNAS TARGET GENES AND THEIR FUNCTIONS ARE OF PARAMOUNT IMPORTANCE. IN THIS ARTICLE WE PRESENT A COMPREHENSIVE REVIEW ABOUT THE ROLE OF MICRORNAS IN H. PYLORI GASTRIC CARCINOGENESIS, IDENTIFYING THE MICRORNAS DOWNREGULATED AND UPREGULATED IN THE INFECTION AND CLARIFYING THEIR BIOLOGICAL ROLE IN THE LINK BETWEEN IMMUNE HOST RESPONSE, INFLAMMATION, DNA METHYLATION AND GASTRIC CARCINOGENESIS. 2015 16 2033 43 EPIGENETIC CHANGES IN SOLID AND HEMATOPOIETIC TUMORS. THERE ARE THREE CONNECTED MOLECULAR MECHANISMS OF EPIGENETIC CELLULAR MEMORY IN MAMMALIAN CELLS: DNA METHYLATION, HISTONE MODIFICATIONS, AND RNA INTERFERENCE. THE FIRST TWO HAVE NOW BEEN FIRMLY LINKED TO NEOPLASTIC TRANSFORMATION. HYPERMETHYLATION OF CPG-RICH PROMOTERS TRIGGERS LOCAL HISTONE CODE MODIFICATIONS RESULTING IN A CELLULAR CAMOUFLAGE MECHANISM THAT SEQUESTERS GENE PROMOTERS AWAY FROM TRANSCRIPTION FACTORS AND RESULTS IN STABLE SILENCING. THIS NORMALLY RESTRICTED MECHANISM IS UBIQUITOUSLY USED IN CANCER TO SILENCE HUNDREDS OF GENES, AMONG WHICH SOME CRITICALLY CONTRIBUTE TO THE NEOPLASTIC PHENOTYPE. VIRTUALLY EVERY PATHWAY IMPORTANT TO CANCER FORMATION IS AFFECTED BY THIS PROCESS. METHYLATION PROFILING OF HUMAN CANCERS REVEALS TISSUE-SPECIFIC EPIGENETIC SIGNATURES, AS WELL AS TUMOR-SPECIFIC SIGNATURES, REFLECTING IN PARTICULAR THE PRESENCE OF EPIGENETIC INSTABILITY IN A SUBSET OF CANCERS AFFECTED BY THE CPG ISLAND METHYLATOR PHENOTYPE. GENERALLY, METHYLATION PATTERNS CAN BE TRACED TO A TISSUE-SPECIFIC, PROLIFERATION-DEPENDENT ACCUMULATION OF ABERRANT PROMOTER METHYLATION IN AGING TISSUES, A PROCESS THAT CAN BE ACCELERATED BY CHRONIC INFLAMMATION AND LESS WELL-DEFINED MECHANISMS INCLUDING, POSSIBLY, DIET AND GENETIC PREDISPOSITION. THE EPIGENETIC MACHINERY CAN ALSO BE ALTERED IN CANCER BY SPECIFIC LESIONS IN EPIGENETIC EFFECTOR GENES, OR BY ABERRANT RECRUITMENT OF THESE GENES BY MUTANT TRANSCRIPTION FACTORS AND COACTIVATORS. EPIGENETIC PATTERNS ARE PROVING CLINICALLY USEFUL IN HUMAN ONCOLOGY VIA RISK ASSESSMENT, EARLY DETECTION, AND PROGNOSTIC CLASSIFICATION. PHARMACOLOGIC MANIPULATION OF THESE PATTERNS-EPIGENETIC THERAPY-IS ALSO POISED TO CHANGE THE WAY WE TREAT CANCER IN THE CLINIC. 2005 17 925 34 CHRONIC INFLAMMATION INDUCES A NOVEL EPIGENETIC PROGRAM THAT IS CONSERVED IN INTESTINAL ADENOMAS AND IN COLORECTAL CANCER. CHRONIC INFLAMMATION REPRESENTS A MAJOR RISK FACTOR FOR TUMOR FORMATION, BUT THE UNDERLYING MECHANISMS HAVE REMAINED LARGELY UNKNOWN. EPIGENETIC MECHANISMS CAN RECORD THE EFFECTS OF ENVIRONMENTAL CHALLENGES ON THE GENOME LEVEL AND COULD THEREFORE PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF INFLAMMATION-ASSOCIATED TUMORS. USING SINGLE-BASE METHYLATION MAPS AND TRANSCRIPTOME ANALYSES OF A COLITIS-INDUCED MOUSE COLON CANCER MODEL, WE IDENTIFIED A NOVEL EPIGENETIC PROGRAM THAT IS CHARACTERIZED BY HYPERMETHYLATION OF DNA METHYLATION VALLEYS THAT ARE CHARACTERIZED BY LOW CPG DENSITY AND ACTIVE CHROMATIN MARKS. THIS PROGRAM IS CONSERVED AND FUNCTIONAL IN MOUSE INTESTINAL ADENOMAS AND RESULTS IN SILENCING OF ACTIVE INTESTINAL GENES THAT ARE INVOLVED IN GASTROINTESTINAL HOMEOSTASIS AND INJURY RESPONSE. FURTHER ANALYSES REVEAL THAT THE PROGRAM REPRESENTS A PROMINENT FEATURE OF HUMAN COLORECTAL CANCER AND CAN BE USED TO CORRECTLY CLASSIFY COLORECTAL CANCER SAMPLES WITH HIGH ACCURACY. TOGETHER, OUR RESULTS SHOW THAT INFLAMMATORY SIGNALS ESTABLISH A NOVEL EPIGENETIC PROGRAM THAT SILENCES A SPECIFIC SET OF GENES THAT CONTRIBUTE TO INFLAMMATION-INDUCED CELLULAR TRANSFORMATION. 2015 18 6865 44 [OXIDATIVE STRESS IN PROSTATE HYPERTROPHY AND CARCINOGENESIS]. AGING, SIGNIFICANT IMPAIRMENT OF THE OXIDATION/REDUCTION BALANCE, INFECTION, AND INFLAMMATION ARE RECOGNIZED RISK FACTORS OF BENIGN HYPERPLASIA AND PROSTATE CANCER. CHRONIC SYMPTOMATIC AND ASYMPTOMATIC PROSTATE INFLAMMATORY PROCESSES GENERATE SIGNIFICANTLY ELEVATED LEVELS OF REACTIVE OXYGEN AND NITROGEN SPECIES, AND HALOGENATED COMPOUNDS. PROSTATE CANCER PATIENTS SHOWED SIGNIFICANTLY HIGHER LIPID PEROXIDATION AND LOWER ANTIOXIDANT LEVELS IN PERIPHERAL BLOOD THAN HEALTHY CONTROLS, WHEREAS PATIENTS WITH PROSTATE HYPERPLASIA DID NOT SHOW SUCH SYMPTOMS. OXIDATIVE/NITROSATIVE/HALOGENATIVE STRESS CAUSES DNA MODIFICATIONS LEADING TO GENOME INSTABILITY THAT MAY INITIATE CARCINOGENESIS; HOWEVER, IT WAS SHOWN THAT OXIDATIVE DAMAGE ALONE IS NOT SUFFICIENT TO INITIATE THIS PROCESS. PEROXIDATION PRODUCTS INDUCED BY REACTIVE OXYGEN AND NITROGEN SPECIES SEEM TO TAKE PART IN EPIGENETIC MECHANISMS REGULATING GENOME ACTIVITY. ONE OF THE MOST COMMON CHANGES OCCURRING IN MORE THAN 90% OF ALL ANALYZED PROSTATE CANCERS IS THE SILENCING OF GSTP1 GENE ACTIVITY. THE GENE ENCODES GLUTATHIONE TRANSFERASE, AN ENZYME PARTICIPATING IN DETOXIFICATION PROCESSES. PROSTATE HYPERPLASIA IS OFTEN ACCOMPANIED BY CHRONIC INFLAMMATION AND SUCH A RELATIONSHIP WAS NOT OBSERVED IN PROSTATE CANCER. THE PARTICIPATION OF INFECTION AND INFLAMMATION IN THE DEVELOPMENT OF HYPERPLASIA IS UNQUESTIONABLE AND THESE FACTORS PROBABLY ALSO TAKE PART IN INITIATING THE EARLY STAGES OF PROSTATE CARCINOGENESIS. THUS IT SEEMS THAT THERAPEUTIC STRATEGIES THAT PREVENT GENOME OXIDATIVE DAMAGE IN SITUATIONS INVOLVING OXIDATIVE/NITROSATIVE/HALOGENATIVE STRESS, I.E. USE OF ANTIOXIDANTS, PLANT STEROIDS, ANTIBIOTICS, AND NON-STEROIDAL ANTI-INFLAMMATORY DRUGS, COULD HELP PREVENT CARCINOGENESIS. 2009 19 2483 35 EPIGENETIC VARIATION AND HUMAN DISEASE. CYTOSINE GUANINE DINUCLEOTIDE (CPG) ISLAND METHYLATION IS A KNOWN MECHANISM OF EPIGENETIC INHERITANCE IN POSTMEIOTIC CELLS. THROUGH ASSOCIATED CHROMATIN CHANGES AND SILENCING, SUCH EPIGENETIC STATES CAN INFLUENCE CELLULAR PHYSIOLOGY AND AFFECT DISEASE RISK AND SEVERITY. OUR STUDIES OF CPG ISLAND METHYLATION IN NORMAL COLORECTAL MUCOSA REVEALED PROGRESSIVE AGE-RELATED INCREASES AT MULTIPLE GENE LOCI, SUGGESTING GENOME-WIDE MOLECULAR ALTERATIONS WITH POTENTIAL TO SILENCE GENE EXPRESSION. HOWEVER, THERE WAS CONSIDERABLE VARIATION IN THE DEGREE OF METHYLATION AMONG INDIVIDUALS OF COMPARABLE AGES. SUCH VARIATION COULD BE RELATED TO GENETIC FACTORS, LIFESTYLE, OR ENVIRONMENTAL EXPOSURES. STUDIES IN ULCERATIVE COLITIS AND HEPATOCELLULAR CIRRHOSIS AND NEOPLASIA REVEALED THAT CHRONIC INFLAMMATORY STATES ARE ACCOMPANIED BY MARKED INCREASES IN CPG ISLAND METHYLATION IN NORMAL-APPEARING TISSUES, CONFIRMING THE HYPOTHESIS THAT PROINFLAMMATORY EXPOSURES COULD ACCOUNT FOR PART OF THE EPIGENETIC VARIATION IN HUMAN POPULATIONS. PRELIMINARY DATA ALSO SUGGEST POTENTIAL INFLUENCES OF LIFESTYLE AND EXPOSURE FACTORS ON CPG ISLAND METHYLATION. IT IS SUGGESTED THAT EPIGENETIC VARIATION RELATED TO AGING, LIFESTYLE, EXPOSURES AND POSSIBLY GENETIC FACTORS, IS ONE OF THE MODULATORS OF ACQUIRED, AGE-RELATED HUMAN DISEASES, INCLUDING NEOPLASIA. 2002 20 1435 54 DIFFERENTIAL METHYLATION LANDSCAPE OF PANCREATIC DUCTAL ADENOCARCINOMA AND ITS PRECANCEROUS LESIONS. BACKGROUND: PANCREATIC CANCER IS ONE OF THE MOST LETHAL DISEASES WITH AN INCIDENCE ALMOST EQUAL TO THE MORTALITY. IN ADDITION TO HAVING GENETIC CAUSES, CANCER CAN ALSO BE CONSIDERED AN EPIGENETIC DISEASE. DNA METHYLATION IS THE PREMIER EPIGENETIC MODIFICATION AND PATTERNS OF ABERRANT DNA METHYLATION ARE RECOGNIZED TO BE A COMMON HALLMARK OF HUMAN TUMOR. IN THE MULTISTAGE CARCINOGENESIS OF PANCREAS STARTING FROM PRECANCEROUS LESIONS TO PANCREATIC DUCTAL ADENOCARCINOMA (PDAC), THE EPIGENETIC CHANGES PLAY A SIGNIFICANT ROLE. DATA SOURCES: RELEVANT STUDIES FOR THIS REVIEW WERE DERIVED VIA AN EXTENSIVE LITERATURE SEARCH IN PUBMED VIA USING VARIOUS KEYWORDS SUCH AS PANCREATIC DUCTAL ADENOCARCINOMA, PRECANCEROUS LESIONS, METHYLATION PROFILE, EPIGENETIC BIOMARKERS THAT ARE RELEVANT DIRECTLY OR CLOSELY ASSOCIATED WITH THE CONCERNED AREA OF OUR INTEREST. THE LITERATURE SEARCH WAS INTENSIVELY DONE CONSIDERING A TIME FRAME OF 20 YEARS (1998-2018). RESULT: IN THIS REVIEW WE HAVE HIGHLIGHTED THE HYPERMETHYLATION AND HYPOMETHYLATION OF THE PRECANCEROUS PDAC LESIONS (PANCREATIC INTRA-EPITHELIAL NEOPLASIA, INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM, MUCINOUS CYSTIC NEOPLASM AND CHRONIC PANCREATITIS) AND PDAC ALONG WITH THE POTENTIAL BIOMARKERS. WE HAVE ALSO ACHIEVED THE EARLY EPIGENETIC DRIVER THAT LEADS TO PROGRESSION FROM PRECANCEROUS LESIONS TO PDAC. A BUNCH OF EPIGENETIC DRIVER GENES LEADS TO PROGRESSION OF PRECANCEROUS LESIONS TO PDAC (PPENK, APC, P14/5/16/17, HMLH1 AND MGMT) ARE ALSO DOCUMENTED. WE SUMMARIZED THE IMPORTANCE OF THESE OBSERVATIONS IN THERAPEUTICS AND DIAGNOSIS OF PDAC HENCE IDENTIFYING THE POTENTIAL USE OF EPIGENETIC BIOMARKERS IN EPIGENETIC TARGETED THERAPY. EPIGENETIC INACTIVATION OCCURS BY HYPERMETHYLATION OF CPG ISLANDS IN THE PROMOTER REGIONS OF TUMOR SUPPRESSOR GENES. WE LISTED ALL HYPER- AND HYPOMETHYLATION OF CPG ISLANDS OF SEVERAL GENES IN PDAC INCLUDING ITS PRECANCEROUS LESIONS. CONCLUSIONS: THE CONCEPT OF THE REVIEW WOULD HELP TO UNDERSTAND THEIR BIOLOGICAL EFFECTS, AND TO DETERMINE WHETHER THEY MAY BE SUCCESSFULLY COMBINED WITH OTHER EPIGENETIC DRUGS. HOWEVER, WE NEED TO CONTINUE OUR RESEARCH TO DEVELOP MORE SPECIFIC DNA-DEMETHYLATING AGENTS, WHICH ARE THE TARGETS FOR HYPERMETHYLATED CPG METHYLATION SITES. 2020