1 6848 133 [MOLECULAR GENETIC AND EPIGENETIC MECHANISMS OF HEPATOCARCINOGENESIS]. HEPATOCELLULAR CARCINOMA (HCC) IS A MAJOR TYPE OF PRIMARY LIVER CANCER AND ONE OF THE MOST FREQUENT HUMAN MALIGNANT NEOPLASMS. COMMON RISK FACTORS OF HUMAN HCC INCLUDE CHRONIC HEPATITIS VIRUS (HBV AND HCV) INFECTION, DIETARY AFLATOXIN B1 (AFB1) INGESTION, CHRONIC ALCOHOL ABUSE, AND CIRRHOSIS ASSOCIATED WITH GENETIC LIVER DISEASES. HEPATOCARCINOGENESIS IS THE RESULT OF INTERACTION BETWEEN HEREDITARY AND ENVIRONMENTAL FACTORS. INHERITANCE DETERMINES INDIVIDUAL SUSCEPTIBILITY TO CANCER; ENVIRONMENT DETERMINES WHICH SUSCEPTIBLE INDIVIDUALS EXPRESS CANCER. STUDIES OF GENETIC AND EPIGENETIC MECHANISMS OF HEPATOCARCINOGENESIS SHOWED THAT HCC DEVELOPMENT IS A COMPLEX POLYGENE AND MULTIPATHWAY PROCESS; THE ACTIVATION OF PROTO-ONCOGENES AND THE INACTIVATION OF TUMOR SUPPRESSOR GENES INDUCED BY GENETIC AND EPIGENETIC ALTERATIONS ARE CORE BIOLOGICAL PROCESSES OF HEPATOCARCINOGENESIS; RB1, P53, AND WNT PATHWAYS ARE COMMONLY AFFECTED IN HCCS OF DIFFERENT ETIOLOGIES, WHICH MAY REFLECT COMMON PATHOLOGIC SEQUENCE OF HCC: CHRONIC LIVER INJURY, CIRRHOSIS, ATYPICAL HYPERPLASTIC NODULES, AND HCC OF EARLY STAGES. HEPATITIS VIRUS INFECTION-ASSOCIATED HCCS HAVE FREQUENT ALTERATIONS IN RB1 PATHWAY, INCLUDING METHYLATION OF P16INK4A AND RB1 GENES AND AMPLIFICATION OF CYCLIN D1. AFB1 EXPOSURE-ASSOCIATED HCCS HAVE FREQUENT ALTERATIONS IN P53 PATHWAY; THE G-->T MUTATION OF P53 GENE AT CODON 249 HAS BEEN IDENTIFIED AS A GENETIC HALLMARK OF HCC CAUSED BY AFB1. ALCOHOLISM-ASSOCIATED HCCS HAVE FREQUENT ALTERATIONS IN BOTH RB1 AND P53 PATHWAYS. THE ROLES OF SOME IMPORTANT GENES RELATED TO CELL APOPTOSIS, DNA REPAIR, DRUG METABOLISM, AND TUMOR METASTASIS IN HEPATOCARCINOGENESIS HAD BEEN DISCUSSED. 2005 2 5969 44 TERT PROMOTER MUTATIONS IN PRIMARY LIVER TUMORS. NEXT-GENERATION SEQUENCING HAS DRAWN THE GENETIC LANDSCAPE OF HEPATOCELLULAR CARCINOMA AND SEVERAL SIGNALING PATHWAYS ARE ALTERED AT THE DNA LEVEL IN TUMORS: WNT/BETA-CATENIN, CELL CYCLE REGULATOR, EPIGENETIC MODIFIER, HISTONE METHYLTRANSFERASE, OXIDATIVE STRESS, RAS/RAF/MAP KINASE AND AKT/MTOR PATHWAYS. HEPATOCARCINOGENESIS IS A MULTISTEP PROCESS STARTING WITH THE EXPOSURE TO DIFFERENT RISK FACTORS, FOLLOWED BY THE DEVELOPMENT OF A CHRONIC LIVER DISEASE AND CIRRHOSIS PRECEDE IN THE VAST MAJORITY OF THE CASES THE DEVELOPMENT OF HCC. SEVERAL LINES OF EVIDENCE HAVE UNDERLINED THE PIVOTAL ROLE OF TELOMERE MAINTENANCE IN BOTH CIRRHOSIS AND HCC PATHOGENESIS. TERT PROMOTER MUTATIONS WERE IDENTIFIED AS THE MOST FREQUENT GENETIC ALTERATIONS IN HEPATOCELLULAR CARCINOMA WITH AN OVERALL FREQUENCY AROUND 60%. MOREOVER, IN CIRRHOSIS, TERT PROMOTER MUTATIONS ARE OBSERVED AT THE EARLY STEPS OF HEPATOCARCINOGENESIS SINCE THEY ARE RECURRENTLY IDENTIFIED IN LOW-GRADE AND HIGH-GRADE DYSPLASTIC NODULES. IN CONTRAST, ACQUISITION OF GENOMIC DIVERSITY THROUGH MUTATIONS OF CLASSICAL ONCOGENES AND TUMOR SUPPRESSOR GENES (TP53, CTNNB1, ARID1A...) OCCURRED ONLY IN PROGRESSED HCC. IN NORMAL LIVER, A SUBSET OF HCC CAN DERIVED FROM THE MALIGNANT TRANSFORMATION OF HEPATOCELLULAR ADENOMA (HCA). IN HCA, CTNNB1 MUTATIONS PREDISPOSE TO TRANSFORMATION OF HCA IN HCC AND TERT PROMOTER MUTATIONS ARE REQUIRED IN MOST OF THE CASES AS A SECOND HIT FOR A FULL MALIGNANT TRANSFORMATION. ALL THESE FINDINGS HAVE REFINED OUR KNOWLEDGE OF HCC PATHOGENESIS AND HAVE POINTED TELOMERASE AS A TARGET FOR TAILORED THERAPY IN THE FUTURE. 2016 3 5338 37 QUANTITATIVE EVALUATION OF RASSF1A METHYLATION IN THE NON-LESIONAL, REGENERATIVE AND NEOPLASTIC LIVER. BACKGROUND: EPIGENETIC CHANGES DURING AGEING AND THEIR RELATIONSHIP WITH CANCER ARE UNDER THE FOCUS OF INTENSE RESEARCH. RASSF1A AND NORE1A ARE NOVEL GENES ACTING IN CONCERT IN THE PROAPOPTOTIC PATHWAY OF THE RAS SIGNALLING. WHILE NORE1A HAS NOT BEEN PREVIOUSLY INVESTIGATED IN THE HUMAN LIVER, RECENT REPORTS HAVE SUGGESTED THAT RASSF1A IS FREQUENTLY EPIGENETICALLY METHYLATED NOT ONLY IN HCC BUT ALSO IN THE CIRRHOTIC LIVER. METHODS: TO ADDRESS WHETHER EPIGENETIC CHANGES TAKE PLACE IN CONNECTION TO AGE AND/OR TO THE UNDERLYING DISEASE, WE INVESTIGATED RASSF1A AND NORE1A GENE PROMOTER METHYLATION BY CONVENTIONAL METHYLATION SPECIFIC PCR AND REAL-TIME MSP IN A SERIES OF HEPATITIC AND NON-HEPATITIC LIVERS HARBORING REGENERATIVE/HYPERPLASTIC (CIRRHOSIS/FOCAL NODULAR HYPERPLASIA), DYSPLASTIC (LARGE REGENERATIVE, LOW AND HIGH GRADE DYSPLASTIC NODULES) AND NEOPLASTIC (HEPATOCELLULAR ADENOMA AND CARCINOMA) GROWTHS. RESULTS: IN THE HEPATITIC LIVER (CHRONIC HEPATITIC/CIRRHOSIS, HEPATOCELLULAR NODULES AND HCC) WE FOUND WIDESPREAD RASSF1A GENE PROMOTER METHYLATION WITH A METHYLATION INDEX THAT INCREASED FROM REGENERATIVE CONDITIONS (CIRRHOSIS) TO HEPATOCELLULAR NODULES (P < 0.01) TO HCC (P < 0.001). IN THE NON-HEPATITIC LIVER A CONSISTENT PATTERN OF GENE METHYLATION WAS ALSO FOUND IN BOTH LESIONAL (FOCAL NODULAR HYPERPLASIA AND HEPATOCELLULAR ADENOMA) AND NON-LESIONAL TISSUE. SPECIFICALLY, HEPATOCELLULAR ADENOMAS (HA) SHOWED A METHYLATION INDEX SIGNIFICANTLY HIGHER THAN THAT DETECTED IN FOCAL NODULAR HYPERPLASIA (FNH) (P < 0.01) AND IN NON-LESIONAL TISSUE (P < 0.001). IN NON-LESIONAL LIVER ALSO THE METHYLATION INDEX GRADUALLY INCREASED BY AGEING (P = 0.002), SUGGESTING A PROGRESSIVE SPREADING OF METHYLATED CELLS OVER TIME. AS OPPOSED TO RASSF1A GENE PROMOTER METHYLATION, NORE1A GENE WAS NEVER FOUND EPIGENETICALLY ALTERATED IN BOTH HEPATITIC AND NON-HEPATITIC LIVER. CONCLUSION: WE HAVE SHOWN THAT IN NON-LESIONAL, REGENERATIVE AND NEOPLASTIC LIVER THE RASSF1A GENE IS INCREASINGLY METHYLATED, THAT THIS CONDITION TAKES PLACE AS AN AGE-RELATED PHENOMENON AND THAT THE EARLY SETTING AND SPREADING OVER TIME OF AN EPIGENETICALLY METHYLATED HEPATOCYTE SUBPOPULATION, MIGHT BE RELATED TO LIVER TUMORIGENESIS. 2006 4 4134 62 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 5 4476 33 MOLECULAR PATHOGENESIS OF HEPATOCELLULAR CARCINOMA. HEPATOCELLULAR CARCINOMA (HCC) IS THE FIFTH MOST COMMON CANCER AND THE THIRD LEADING CAUSE OF CANCER DEATH WORLDWIDE. HEPATOCARCINOGENESIS IS A MULTISTEP PROCESS EVOLVING FROM NORMAL THROUGH CHRONIC HEPATITIS/CIRRHOSIS AND DYSPLASTIC NODULES TO HCC. WITH ADVANCES IN MOLECULAR METHODS, THERE IS A GROWING UNDERSTANDING OF THE MOLECULAR MECHANISMS IN HEPATOCARCINOGENESIS. HEPATOCARCINOGENESIS IS STRONGLY LINKED TO INCREASES IN ALLELIC LOSSES, CHROMOSOMAL CHANGES, GENE MUTATIONS, EPIGENETIC ALTERATIONS AND ALTERATIONS IN MOLECULAR CELLULAR PATHWAYS. SOME OF THESE ALTERATIONS ARE ACCOMPANIED BY A STEPWISE INCREASE IN THE DIFFERENT PATHOLOGICAL DISEASE STAGES IN HEPATOCARCINOGENESIS. OVERALL, A DETAILED UNDERSTANDING OF THE UNDERLYING MOLECULAR MECHANISMS INVOLVED IN THE PROGRESSION OF HCC IS OF FUNDAMENTAL IMPORTANCE TO THE DEVELOPMENT OF EFFECTIVE PREVENTION AND TREATMENT REGIMES FOR HCC. 2008 6 6486 58 TP53 AND LIVER CARCINOGENESIS. PRIMARY HEPATOCELLULAR CARCINOMA (HCC) IS ONE OF THE MOST COMMON MALIGNANCIES AND HAS THE FOURTH HIGHEST MORTALITY RATE WORLDWIDE. THE MAJOR RISK FACTORS, INCLUDING CHRONIC INFECTIONS WITH THE HEPATITIS B OR C VIRUS, ARE EXPOSURE TO DIETARY AFLATOXIN B1(AFB1), VINYL CHLORIDE, OR ALCOHOL CONSUMPTION. SOUTHERN CHINA AND SUB-SAHARAN AFRICA HAVE THE HIGHEST DIETARY AFB1 EXPOSURE, MAKING IT AND HEPATITIS B VIRUS (HBV) THE MAJOR CAUSES OF CANCER MORTALITY IN THESE GEOGRAPHIC AREAS. RECENT STUDIES HAVE DISCOVERED GENETIC AND EPIGENETIC CHANGES INVOLVED IN THE MOLECULAR PATHOGENESIS OF HCC, INCLUDING SOMATIC MUTATIONS IN THE P53 TUMOR SUPPRESSOR GENE (TP53). AFB1 INDUCES TYPICAL G:C TO T:A TRANSVERSIONS AT THE THIRD BASE IN CODON 249 OF P53. CHRONIC ACTIVE HEPATITIS B AND C (HCV) INFECTION, AND FURTHER INFLAMMATORY AND OXYRADICAL DISORDERS INCLUDING WILSON DISEASE (WD) OR HEMOCHROMATOSIS, GENERATE REACTIVE OXYGEN/NITROGEN SPECIES THAT CAN DAMAGE DNA AND MUTATE THE P53 GENE. THE X GENE OF HBV (HBX) IS THE MOST COMMON OPEN READING FRAME INTEGRATED INTO THE HOST GENOME IN HCC. THE INTEGRATED HBX IS FREQUENTLY MUTATED AND HAS A DIMINISHED ABILITY TO FUNCTION AS A TRANSCRIPTIONAL COTRANSACTIVATOR AND TO ACTIVATE THE NF-KAPPA B PATHWAY. HOWEVER, THE MUTANT HBX PROTEINS STILL RETAIN THEIR ABILITY TO BIND TO AND ABROGATE P53-MEDIATED APOPTOSIS. IN SUMMARY, BOTH VIRUSES AND CHEMICALS ARE IMPLICATED IN THE ETIOLOGY AND MOLECULAR PATHOGENESIS OF HCC. THE RESULTANT MOLECULAR CHANGES IN THE RAS AND WNT SIGNAL-TRANSDUCTION PATHWAYS, AND THE P53 AND RB TUMOR SUPPRESSOR PATHWAYS SIGNIFICANTLY CONTRIBUTE TO LIVER CARCINOGENESIS 2003 7 1042 29 CLINICAL AND MOLECULAR BASIS OF HEPATOCELLULAR CARCINOMA AFTER HEPATITIS C VIRUS ERADICATION. HEPATOCELLULAR CARCINOMA (HCC) ARISES IN THE BACKGROUND OF CHRONIC LIVER DISEASES, INCLUDING HEPATITIS AND LIVER CIRRHOSIS CAUSED BY HEPATITIS C VIRUS (HCV) INFECTION. IT IS WELL KNOWN THAT HCV ERADICATION USING ANTIVIRAL DRUGS CAN EFFICIENTLY INHIBIT HEPATOCARCINOGENESIS. RECENT ADVANCES IN AND DEVELOPMENT OF DIRECT-ACTING ANTIVIRAL (DAA) DRUGS HAS REVOLUTIONIZED THE TREATMENT OF HCV INFECTION, AND THE VAST MAJORITY OF HCV PATIENTS CAN ACHIEVE HCV ERADICATION USING DAAS. HOWEVER, MOUNTING EVIDENCE CLEARLY INDICATES THAT HCC INEVITABLY OCCURS IN A SUBSET OF PATIENTS AFTER SUCCESSFUL VIRAL ERADICATION USING DAA THERAPY. CANCER IS A GENETIC DISEASE, AND THE ACCUMULATION OF GENETIC AND EPIGENETIC ABERRATIONS MAY CAUSE HEPATOCARCINOGENESIS IN CHRONICALLY DAMAGED LIVER, EVEN AFTER VIRUS ELIMINATION. IN THIS REVIEW, WE HIGHLIGHT HCC DEVELOPMENT AFTER HCV ERADICATION AND DISCUSS THE CURRENT UNDERSTANDING OF THE MOLECULAR MECHANISMS OF TUMORIGENESIS AFTER VIRUS ELIMINATION, FOCUSING ON THE GENETIC AND EPIGENETIC BACKGROUND OF CHRONICALLY DAMAGED LIVER TISSUES. 2022 8 4454 36 MOLECULAR MECHANISMS DRIVING PROGRESSION OF LIVER CIRRHOSIS TOWARDS HEPATOCELLULAR CARCINOMA IN CHRONIC HEPATITIS B AND C INFECTIONS: A REVIEW. ALMOST ALL PATIENTS WITH HEPATOCELLULAR CARCINOMA (HCC), A MAJOR TYPE OF PRIMARY LIVER CANCER, ALSO HAVE LIVER CIRRHOSIS, THE SEVERITY OF WHICH HAMPERS EFFECTIVE TREATMENT FOR HCC DESPITE RECENT PROGRESS IN THE EFFICACY OF ANTICANCER DRUGS FOR ADVANCED STAGES OF HCC. HERE, WE REVIEW RECENT KNOWLEDGE CONCERNING THE MOLECULAR MECHANISMS OF LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC FROM GENETIC AND EPIGENOMIC POINTS OF VIEW. BECAUSE ~70% OF PATIENTS WITH HCC HAVE HEPATITIS B VIRUS (HBV) AND/OR HEPATITIS C VIRUS (HCV) INFECTION, WE FOCUSED ON HBV- AND HCV-ASSOCIATED HCC. THE LITERATURE SUGGESTS THAT GENETIC AND EPIGENETIC FACTORS, SUCH AS MICRORNAS, PLAY A ROLE IN LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC, AND THAT HBV- AND HCV-ENCODED PROTEINS APPEAR TO BE INVOLVED IN HEPATOCARCINOGENESIS. FURTHER STUDIES ARE NEEDED TO ELUCIDATE THE MECHANISMS, INCLUDING IMMUNE CHECKPOINTS AND MOLECULAR TARGETS OF KINASE INHIBITORS, ASSOCIATED WITH LIVER CIRRHOSIS AND ITS PROGRESSION TO HCC. 2019 9 442 25 ANTIVIRAL THERAPIES FOR HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOMA. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS A CRITICAL RISK FACTOR FOR THE CARCINOGENESIS AND PROGRESSION OF HEPATOCELLULAR CARCINOMA (HCC). IT PROMOTES HCC DEVELOPMENT BY INDUCING LIVER FIBROGENESIS, GENETIC AND EPIGENETIC ALTERATIONS, AND THE EXPRESSION OF ACTIVE VIRAL-CODED PROTEINS. EFFECTIVE ANTIVIRAL TREATMENTS INHIBIT THE REPLICATION OF HBV, REDUCE SERUM VIRAL LOAD AND ACCELERATE HEPATITIS B E ANTIGEN SERUM CONVERSION. TIMELY INITIATION OF ANTIVIRAL TREATMENT IS NOT ONLY ESSENTIAL FOR PREVENTING THE INCIDENCE OF HCC IN CHRONIC HEPATITIS B PATIENTS, BUT ALSO IMPORTANT FOR REDUCING HBV REACTIVATION, IMPROVING LIVER FUNCTION, REDUCING OR DELAYING HCC RECURRENCE, AND PROLONGING OVERALL SURVIVAL OF HBV-RELATED HCC PATIENTS AFTER CURATIVE AND PALLIATIVE THERAPIES. THE SELECTION OF ANTIVIRAL DRUGS, MONITORING OF INDICATORS SUCH AS HBV DNA AND HEPATITIS B SURFACE ANTIGEN, AND TIMELY RESCUE TREATMENT WHEN NECESSARY, ARE ESSENTIAL IN ANTIVIRAL THERAPIES FOR HBV-RELATED HCC. 2015 10 3567 40 IMPACT OF HEPATITIS VIRUS AND AGING ON DNA METHYLATION IN HUMAN HEPATOCARCINOGENESIS. HEPATOCELLULAR CARCINOMA (HCC) USUALLY DEVELOPS ON THE BASIS OF CHRONIC HEPATITIS AND LIVER CIRRHOSIS, WHERE INACTIVATION OF SEVERAL TUMOR SUPPRESSOR GENES (TSGS) TAKES PLACE VIA METHYLATION OF THE PROMOTER. INTERESTINGLY, THESE METHYLATION EVENTS ARE MORE PREVALENT IN A BACKGROUND LIVER AT HIGH RISK OF HCC THAN ONE AT LOW RISK. ABNORMAL METHYLATION IS ALSO OBSERVED IN PRECANCEROUS NODULES SUCH AS DYSPLASTIC NODULES AND ADENOMAS, SUGGESTING THAT EPIGENETIC ALTERATION IS AN EARLY EVENT FOR HCC CARCINOGENESIS. IT IS POSSIBLE THAT INFECTION WITH THE HEPATITIS VIRUS INDUCES ALTERATION OF METHYLATION AT PROMOTERS OF TSGS. SOME STUDIES SUGGESTED THAT VIRAL PROTEINS INTERFERE WITH DNA METHYLTRANSFERASE IN CHRONIC HEPATITIS B. INDUCTION OF EPIGENETIC ALTERATION IN CHRONIC HEPATITIS C MIGHT, HOWEVER, MIGHT BE A CONSEQUENCE OF OXIDATIVE STRESS. IN ADDITION, WE PROPOSED AGE SHOULD BE TAKEN INTO CONSIDERATION FOR HCC DEVELOPMENT VIA EPIGENETIC PATHWAYS. FURTHER INVESTIGATIONS ARE REQUIRED TO UNDERSTAND THE MECHANISM OF INDUCING EPIGENETIC INSTABILITY DURING HEPATOCARCINOGENESIS. 2010 11 3272 69 HEPATOCELLULAR CARCINOMA: AN UPDATE. HEPATOCELLULAR CARCINOMA (HCC) IS THE MOST COMMON MALIGNANT TUMOR OF MALES IN THE WORLD, WITH AN INCIDENCE OF 1,000,000 NEW CASES A YEAR. IT IS ENDEMIC IN SOUTHEAST ASIA AND SUB-SAHARAN AFRICA. RISK FACTORS INCLUDE CHRONIC INFECTION WITH HEPATITIS B VIRUS (HBV) AND HEPATITIS C VIRUS (HCV), AFLATOXIN B1 UPTAKE, HEMOCHROMATOSIS, AND ALPHA1 -ANTITRIPSIN DEFICIENCY. EPIDEMIOLOGICAL STUDIES PROVIDE EVIDENCE FOR THE ASSOCIATION OF HCC WITH HBV INFECTION. THE INCIDENCE OF HCC IS HIGH IN REGIONS HYPERENDEMIC FOR HBV. CHRONIC CARRIER STATE AND MATERNAL-INFANT TRANSMISSION ARE IMPORTANT FACTORS IN THE DEVELOPMENT OF HCC. EVIDENCE OF DIRECT ONCOGENIC EFFECT OF H BV IS WELL ESTABLISHED, HCCS CONTAIN VIRAL DNA SEQUENCES INTEGRATED INTO HEPATOCYTE DNA THAT ACT AS RANDOM INSERTIONAL MUTAGENS, AND THESE SITES ARE NEAR GENES INVOLVED IN THE CONTROL OF PROLIFERATION AND DIFFERENTIATION. THE MECHANISM OF HEPATITIS C VIRUS IN HEPATOCARCINOGENESIS IS STILL IMPRECISE BUT A HIGH PERCENTAGE OF CASES ARE RELATED TO THIS VIRUS. CHRONIC ALCOHOL CONSUMPTION AND CIRRHOSIS ARE COFACTORS THAT INCREASE THE DEVELOPMENT OF HCC IN PATIENTS WITH CHRONIC VIRAL INFECTION. IN EXPERIMENTAL CARCINOGENESIS A MULTIPOTENTIAL ELEMENT CALLED OVAL CELL PROLIFERATES IN THE EARLY STAGES. THE CELLULAR EVENTS ARE ACCOMPANIED BY INCREASED EXPRESSION OF SEVERAL GROWTH FACTORS THAT ENHANCE THE SURVIVAL OF CARCINOGEN-ACTIVATED CELLS BY SUPPRESSING APOPTOSIS AND INCREASING ELEMENTS ENTERING THE CELL CYCLE. HEPATIC CARCINOGENESIS IS A COMPLEX PROCESS ASSOCIATED WITH ACCUMULATION OF GENETIC AND EPIGENETIC CHANGES THAT RUN THROUGH STEPS OF INITIATION, PROMOTION AND PROGRESSION. ACTIVATION OF ONCOGENES OF THE "RAS" FAMILY AND OTHERS HAS BEEN DETECTED DURING CHEMICALLY-INDUCED HCC IN RODENTS, BUT THERE IS LITTLE EVIDENCE OF SUCH ACTIVATION IN HUMAN TUMORS. THE ROLE OF TUMOR SUPRESSOR GENES SUCH AS RETINOBLASTOMA (RB) AND P53 GENES HAS BEEN DOCUMENTED. AFLATOXIN B1 THAT CONTAMINATES FOODS IN ENDEMIC AREAS HAS A CLEAR ROLE IN HEPATOCARCINOGENESIS. METABOLITES OF THIS TOXIN PROMOTE APURINIC SITES AND G TO T MUTATIONS IN CHROMOSOMAL DNA, THE THIRD BASE OF CODON 249 OF THE P53 GENE IS PREFERENTIALLY TARGETED TO FORM ADUCTS WITH AFLATOXIN B1, AND THIS MUTATION HAS BEEN SPECIFICALLY IDENTIFIED IN HBV INFECTION. HISTOLOGICAL AND CYTOLOGICAL CRITERIA FOR THE DIAGNOSIS OF HCC ARE WELL ESTABLISHED AND ARE BASED IN ARCHITECTURAL AND CYTOLOGICAL CHANGES. AN IMPORTANT ISSUE IS THE DIAGNOSIS OF LIVER "NODULES" DETECTED BY IMAGE, FROM WHICH SMALL BIOPSIES OR ASPIRATION MATERIAL IS OBTAINED. SPECIAL STUDIES SUCH AS RETICULIN, CD34, CYTOKERATIN PROFILE, AND MOC-31 CAN BE VERY USEFUL FOR THE DIFFERENTIAL DIAGNOSIS OF PRIMARY AND METASTATIC TUMORS. TELOMERASE ACTIVITY HAS BEEN FOUND IN HCC AND NEGATIVE IN PERICANCEROUS TISSUE. IT IS MORE PRONOUNCED IN POORLY DIFFERENTIATED TUMORS AND CORRELATES WITH FACTORS OF CLINICAL IMPORTANCE, SUCH AS PROGNOSIS AND RECURRENCES. CELLS OF WELL-DIFFERENTIATED HCC HAVE AN ULTRASTRUCTURAL APPEARANCE SIMILAR TO NORMAL HEPATOCYTES. DURING THE PROCESS OF DEDIFFERENTIATION, THERE IS PROGRESSIVE LOSS OF ORGANIZATION OF INTRACELLULAR ORGANELLES. THE CELL COHESION IS LOST, INTERCELLULAR GAPS WITH MICROVILLI APPEAR, THE SINUSOIDS BECOME CAPILLARIZED, AND REPARATIVE CHANGES ARE SEEN IN THE SPACES OF DISSE. A VARIETY OF INCLUSIONS, SUCH AS MALLORY BODIES, GRANULAR MATERIAL, SECONDARY LYSOSOMES, AND DUBIN-JOHNSON PIGMENT, HAVE BEEN DESCRIBED. FIBROLAMELLAR CARCINOMA HAS A CHARACTERISTIC HISTOLOGICAL PICTURE AND ULTRASTRUCTURALLY ONCOCYTIC FEATURES. NEUROENDOCRINE GRANULES AND COMBINATION OF HCC WITH BILE DUCT CARCINOMA ARE SEEN BY ELECTRON MICROSCOPY. 2001 12 6868 37 [PATHOGENESIS OF HEPATITIS B VIRUS-RELATED HEPATOCELLULAR CARCINOMA]. HEPATOCELLULAR CARCINOMA (HCC) IS ONE OF THE MOST COMMON CANCER WORLDWIDE. MOST OF THE HCC OCCUR IN DEVELOPING COUNTRIES. CHRONIC HEPATITIS B VIRUS (HBV) INFECTION IS AN IMPORTANT RISK FACTOR FOR HCC DEVELOPMENT. HBV INDUCES IMMUNE-MEDIATED CHRONIC HEPATITIS, LIVER INJURY, REGENERATION AND SCAR FORMING RESPONSES, LEADING TO AN INFLAMMATORY, FIBROTIC AND IMMUNE DEFICIENT MICROENVIRONMENT. HBV MAY INTEGRATE INTO HOST GENOME, INDUCING GENETIC ABNORMALITY AND ALTERING THE EXPRESSION OF HCC-RELATED GENES. HBV ALSO EXPRESSES ACTIVE PROTEINS SUCH AS X (HBX) AND S PROTEINS, WHICH MAY TRANS-ACTIVATE HCC-RELATED PROTEINS EXPRESSION, INTERACT WITH INTRACELLULAR SPECIFIC PROTEINS, ACTIVATE A VARIETY OF SIGNALING PATHWAYS, AND INDUCE ABERRANT EPIGENETIC MODIFICATIONS. HBV MUTATION ALSO HAS IMPACT ON HBV RELATED HCC DEVELOPMENT. 2016 13 4903 31 P16 PROMOTER HYPERMETHYLATION IN HUMAN HEPATOCELLULAR CARCINOMA WITH OR WITHOUT HEPATITIS VIRUS INFECTION. BACKGROUND: EPIGENETIC ALTERATION THROUGH METHYLATION IS ONE OF THE MOST IMPORTANT STEPS IN CARCINOGENESIS. HOWEVER, THE RELATION BETWEEN HEPATITIS VIRUS INFECTION AND EPIGENETIC ALTERATIONS IS POORLY UNDERSTOOD. METHODS: SIXTEEN PATIENTS WITHOUT HEPATITIS B VIRUS (HBV) AND HEPATITIS C VIRUS (HCV) AND 35 PATIENTS WITH HBV OR HCV WHO UNDERWENT LIVER RESECTION FOR HEPATOCELLULAR CARCINOMA (HCC) WERE STUDIED. MUTATION OF P53 WAS DETECTED BY DIRECT SEQUENCING. METHYLATION STATUS OF P16 WAS EVALUATED IN TUMOR AND NONCANCEROUS LIVER TISSUES BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. RESULTS: IN HCC WITHOUT HBV AND HCV, P53 MUTATIONS WERE DETECTED IN 5 (31%) OF 16 HCCS. METHYLATION OF P16 PROMOTER WAS DETECTED IN 2 (25%) OF 8 MODERATELY DIFFERENTIATED HCCS, 6 (75%) OF 8 POORLY DIFFERENTIATED HCCS, AND NONE OF 16 NONCANCEROUS TISSUE SPECIMENS. IN HCC WITH HBV OR HCV, P53 MUTATIONS WERE DETECTED IN 8 (23%) OF 35 HCCS. METHYLATION OF P16 PROMOTER WAS DETECTED IN 2 (100%) OF 2 WELL-DIFFERENTIATED HCCS, 13 (76%) OF 17 MODERATELY DIFFERENTIATED HCCS, 12 (75%) OF 16 POORLY DIFFERENTIATED HCCS, AND 9 (26%) OF 35 NONCANCEROUS LIVER TISSUE SPECIMENS. CONCLUSIONS: OUR RESULTS SUGGEST THAT HEPATITIS VIRUSES MIGHT INDUCE METHYLATION OF P16 PROMOTER IN LIVER WITH CHRONIC INFLAMMATION, BEFORE APPEARANCE OF HCC. 2004 14 4477 34 MOLECULAR PATHOGENESIS OF HUMAN HEPATOCELLULAR CARCINOMA. HEPATOCARCINOGENESIS IS A SLOW PROCESS DURING WHICH GENOMIC CHANGES PROGRESSIVELY ALTER THE HEPATOCELLULAR PHENOTYPE TO PRODUCE CELLULAR INTERMEDIATES THAT EVOLVE INTO HEPATOCELLULAR CARCINOMA. DURING THE LONG PRENEOPLASTIC STAGE, IN WHICH THE LIVER IS OFTEN THE SITE OF CHRONIC HEPATITIS, CIRRHOSIS, OR BOTH, HEPATOCYTE CYCLING IS ACCELERATED BY UPREGULATION OF MITOGENIC PATHWAYS, IN PART THROUGH EPIGENETIC MECHANISMS. THIS LEADS TO THE PRODUCTION OF MONOCLONAL POPULATIONS OF ABERRANT AND DYSPLASTIC HEPATOCYTES THAT HAVE TELOMERE EROSION AND TELOMERASE RE-EXPRESSION, SOMETIMES MICROSATELLITE INSTABILITY, AND OCCASIONALLY STRUCTURAL ABERRATIONS IN GENES AND CHROMOSOMES. DEVELOPMENT OF DYSPLASTIC HEPATOCYTES IN FOCI AND NODULES AND EMERGENCE OF HEPATOCELLULAR CARCINOMA ARE ASSOCIATED WITH THE ACCUMULATION OF IRREVERSIBLE STRUCTURAL ALTERATIONS IN GENES AND CHROMOSOMES, BUT THE GENOMIC BASIS OF THE MALIGNANT PHENOTYPE IS HETEROGENEOUS. THE MALIGNANT HEPATOCYTE PHENOTYPE MAY BE PRODUCED BY THE DISRUPTION OF A NUMBER OF GENES THAT FUNCTION IN DIFFERENT REGULATORY PATHWAYS, PRODUCING SEVERAL MOLECULAR VARIANTS OF HEPATOCELLULAR CARCINOMA. NEW STRATEGIES SHOULD ENABLE THESE VARIANTS TO BE CHARACTERIZED. 2002 15 6797 39 [EPIDEMIOLOGY, NATURAL HISTORY AND PATHOGENESIS OF HEPATOCELLULAR CARCINOMA]. HEPATOCELLULAR CARCINOMA (HCC) IS THE MAIN TYPE OF PRIMARY LIVER CANCERS AND THE THIRD MOST COMMON CAUSE OF CANCER MORTALITY WORLDWIDE. IN FRANCE, RISING NUMBER BETWEEN 5000 AND 6000 CASES ARE DIAGNOSED EACH YEAR. THE MAJOR RISK FACTOR FOR HEPATOCELLULAR CARCINOMA IS CHRONIC HEPATITIS: VIRAL HEPATITIS B, VIRAL HEPATITIS C, CONSUMPTION OF ALCOHOL, HEMOCHROMATOSIS. HEPATOCELLULAR CARCINOMA IS CLOSELY ASSOCIATED TO LIVER CIRRHOSIS, WHICH IS A TRUE PRECANCEROUS STATE. BECAUSE HEPATOCARCINOGENESIS IS A LONG AND HETEROGENEOUS PROCESS, THERE IS STILL MUCH TO UNDERSTAND. MANY GENETIC AND EPIGENETIC ALTERATIONS ARE DESCRIBED LEADING TO CHANGES IN CELLULAR SIGNALLING CASCADES INVOLVED IN REGULATION OF GROWTH, DIFFERENTIATION, APOPTOSIS, MOTILITY. HEPATITIS VIRUSES PLAY A DIRECT ONCOGENIC ROLE THROUGH THE INTERACTION BETWEEN VIRAL AND CELLULAR PROTEINS, WHICH CONTROL CELL HOMEOSTASIS, OR BY THE INTEGRATION OF HEPATITIS B VIRUS GENOME INTO THE HOST GENOME. FURTHERMORE, HEPATITIS VIRUSES PLAY AN INDIRECT ONCOGENIC ROLE BY CAUSING CHRONIC INFLAMMATION AND HEPATOCYTE REGENERATION RELATED TO VIRAL HEPATOPATHY. IN EXPECTATION OF A BETTER UNDERSTANDING OF HEPATOCARCINOGENESIS AND NEW TREATMENTS, PREVENTION FROM RISK FACTORS AND ULTRASONOGRAPHIC SCREENING OF PATIENTS WITH CIRRHOSIS SHOULD INCREASE PROGNOSIS. 2011 16 5731 35 SMAD3 PHOSPHO-ISOFORM SIGNALING IN HEPATITIS C VIRUS-RELATED CHRONIC LIVER DISEASES. THE RISK OF HEPATOCELLULAR CARCINOMA (HCC) DEVELOPMENT INCREASES AS HEPATITIS VIRUS C (HCV)-RELATED LIVER DISEASES PROGRESS, ESPECIALLY IN PATIENTS WITH ACTIVE INFLAMMATION. INSIGHT INTO HEPATIC CARCINOGENESIS HAVE EMERGED FROM RECENT DETAILED ANALYSES OF TRANSFORMING GROWTH FACTOR-BETA AND C-JUN-N-TERMINAL KINASE SIGNALING PROCESSES DIRECTED BY MULTIPLE PHOSPHORYLATED (PHOSPHO)-ISOFORMS OF A SMAD3 MEDIATOR. IN THE COURSE OF HCV-RELATED CHRONIC LIVER DISEASES, CHRONIC INFLAMMATION AND HOST GENETIC/EPIGENETIC ALTERATIONS ADDITIVELY SHIFT THE HEPATOCYTIC SMAD3 PHOSPHO-ISOFORM SIGNALING FROM TUMOR SUPPRESSION TO CARCINOGENESIS, INCREASING THE RISK OF HCC. CHRONIC INFLAMMATION REPRESENTS AN EARLY CARCINOGENIC STEP THAT PROVIDES A NONMUTAGENIC TUMOR-PROMOTING STIMULUS. AFTER UNDERGOING SUCCESSFUL ANTIVIRAL THERAPY, PATIENTS WITH CHRONIC HEPATITIS C COULD EXPERIENCE A LOWER RISK OF HCC AS SMAD3 PHOSPHO-ISOFORM SIGNALING REVERSES FROM POTENTIAL CARCINOGENESIS TO TUMOR SUPPRESSION. EVEN AFTER HCV CLEARANCE, HOWEVER, PATIENTS WITH CIRRHOSIS COULD STILL DEVELOP HCC BECAUSE OF SUSTAINED, INTENSE CARCINOGENIC SMAD3 PHOSPHO-ISOFORM SIGNALING THAT IS POSSIBLY CAUSED BY GENETIC OR EPIGENETIC ALTERATIONS. SMAD3 PHOSPHO-ISOFORMS SHOULD ASSIST WITH EVALUATING THE EFFECTIVENESS OF INTERVENTIONS AIMED AT REDUCING HUMAN HCC. 2014 17 6271 40 THE ONCOGENIC ROLE OF HEPATITIS B VIRUS. THE HEPATITIS B VIRUS (HBV) IS A SMALL ENVELOPED DNA VIRUS THAT CAUSES ACUTE AND CHRONIC HEPATITIS. HBV INFECTION IS A WORLD HEALTH PROBLEM, WITH 350 MILLION CHRONICALLY INFECTED PEOPLE AT INCREASED RISK OF DEVELOPING LIVER DISEASE AND HEPATOCELLULAR CARCINOMA (HCC). HBV HAS BEEN CLASSIFIED AMONG HUMAN TUMOR VIRUSES BY VIRTUE OF A ROBUST EPIDEMIOLOGIC ASSOCIATION BETWEEN CHRONIC HBV CARRIAGE AND HCC OCCURRENCE. IN THE ABSENCE OF CYTOPATHIC EFFECT IN INFECTED HEPATOCYTES, THE ONCOGENIC ROLE OF HBV MIGHT INVOLVE A COMBINATION OF DIRECT AND INDIRECT EFFECTS OF THE VIRUS DURING THE MULTISTEP PROCESS OF LIVER CARCINOGENESIS. LIVER INFLAMMATION AND HEPATOCYTE PROLIFERATION DRIVEN BY HOST IMMUNE RESPONSES ARE RECOGNIZED DRIVING FORCES OF LIVER CELL TRANSFORMATION. GENETIC AND EPIGENETIC ALTERATIONS CAN ALSO RESULT FROM VIRAL DNA INTEGRATION INTO HOST CHROMOSOMES AND FROM PROLONGED EXPRESSION OF VIRAL GENE PRODUCTS. NOTABLY, THE TRANSCRIPTIONAL REGULATORY PROTEIN HBX ENCODED BY THE X GENE IS ENDOWED WITH TUMOR PROMOTER ACTIVITY. HBX HAS PLEIOTROPIC ACTIVITIES AND PLAYS A MAJOR ROLE IN HBV PATHOGENESIS AND IN LIVER CARCINOGENESIS. BECAUSE HEPATIC TUMORS CARRY A DISMAL PROGNOSIS, THERE IS URGENT NEED TO DEVELOP EARLY DIAGNOSTIC MARKERS OF HCC AND EFFECTIVE THERAPIES AGAINST CHRONIC HEPATITIS B. DECIPHERING THE ONCOGENIC MECHANISMS THAT UNDERLIE HBV-RELATED TUMORIGENESIS MIGHT HELP DEVELOPING ADAPTED THERAPEUTIC STRATEGIES. 2014 18 3394 38 HOST EPIGENETIC ALTERATIONS AND HEPATITIS B VIRUS-ASSOCIATED HEPATOCELLULAR CARCINOMA. HEPATOCELLULAR CARCINOMA (HCC) IS THE MOST FREQUENT PRIMARY MALIGNANCY OF THE LIVER AND A LEADING CAUSE OF CANCER-RELATED DEATHS WORLDWIDE. ALTHOUGH MUCH PROGRESS HAS BEEN MADE IN HCC DRUG DEVELOPMENT IN RECENT YEARS, TREATMENT OPTIONS REMAIN LIMITED. THE MAJOR CAUSE OF HCC IS CHRONIC HEPATITIS B VIRUS (HBV) INFECTION. DESPITE THE EXISTENCE OF A VACCINE, MORE THAN 250 MILLION INDIVIDUALS ARE CHRONICALLY INFECTED BY HBV. CURRENT ANTIVIRAL THERAPIES CAN REPRESS VIRAL REPLICATION BUT TO DATE THERE IS NO CURE FOR CHRONIC HEPATITIS B. OF NOTE, INHIBITION OF VIRAL REPLICATION REDUCES BUT DOES NOT ELIMINATE THE RISK OF HCC DEVELOPMENT. HBV CONTRIBUTES TO LIVER CARCINOGENESIS BY DIRECT AND INDIRECT EFFECTS. THIS REVIEW SUMMARIZES THE CURRENT KNOWLEDGE OF HBV-INDUCED HOST EPIGENETIC ALTERATIONS AND THEIR ASSOCIATION WITH HCC, WITH AN EMPHASIS ON THE INTERACTIONS BETWEEN HBV PROTEINS AND THE HOST CELL EPIGENETIC MACHINERY LEADING TO MODULATION OF GENE EXPRESSION. 2021 19 1478 32 DIVERSE ROLES OF HEPATITIS B VIRUS IN LIVER CANCER. HEPATITIS B VIRUS (HBV) IS A WIDESPREAD HUMAN PATHOGEN RESPONSIBLE FOR ACUTE AND CHRONIC LIVER DISEASES. THE HEPATITIS B BURDEN IS PARTICULARLY HEAVY IN ENDEMIC COUNTRIES, WHERE LIVER CIRRHOSIS AND HEPATOCELLULAR CARCINOMA ARE LEADING CAUSES OF DEATH. HOWEVER, THE ONCOGENIC ROLE OF HBV REMAINS ENIGMATIC. AS THE VIRUS HAS NO CYTOPATHIC EFFECT, LIVER DAMAGE IS ATTRIBUTED TO IMMUNE RESPONSES THAT INDUCE INFLAMMATION, APOPTOSIS AND REGENERATION, FOSTERING THE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS. IN A MORE DIRECT ACTION, FREQUENT INTEGRATION OF HBV DNA INTO HOST CHROMOSOMES MAY LEAD TO INSERTIONAL MUTAGENESIS OF CANCER-RELATED GENES AND CHROMOSOMAL INSTABILITY. HBV PROTEINS, NOTABLY THE HBX TRANSACTIVATOR, PARTICIPATE AS CO-FACTORS IN ONCOGENESIS. BETTER UNDERSTANDING OF HEPATITIS B PATHOGENESIS IS MANDATORY FOR IMPROVING DISEASE MANAGEMENT. 2012 20 2980 37 GENETIC BASIS OF HEPATITIS VIRUS-ASSOCIATED HEPATOCELLULAR CARCINOMA: LINKAGE BETWEEN INFECTION, INFLAMMATION, AND TUMORIGENESIS. HEPATITIS VIRUS INFECTION IS A LEADING CAUSE OF CHRONIC LIVER DISEASE, INCLUDING CIRRHOSIS AND HEPATOCELLULAR CARCINOMA (HCC). ALTHOUGH ANTI-VIRAL THERAPIES AGAINST HEPATITIS B VIRUS (HBV) AND HEPATITIS C VIRUS (HCV) HAVE DRAMATICALLY PROGRESSED DURING THE PAST DECADE, THE ESTIMATED NUMBER OF PEOPLE CHRONICALLY INFECTED WITH HBV AND/OR HCV IS ~370 MILLION, AND HEPATITIS VIRUS-ASSOCIATED HEPATOCARCINOGENESIS IS A SERIOUS HEALTH CONCERN WORLDWIDE. UNDERSTANDING THE MECHANISM OF VIRUS-ASSOCIATED CARCINOGENESIS IS CRUCIAL TOWARD BOTH TREATMENT AND PREVENTION, AND THE RECENTLY DEVELOPED WHOLE GENOME/EXOME SEQUENCING ANALYSIS USING NEXT-GENERATION SEQUENCING TECHNOLOGIES HAS CONTRIBUTED TO UNVEILING THE LANDSCAPE OF GENETIC AND EPIGENETIC ABERRATIONS IN NOT ONLY TUMOR TISSUES BUT ALSO THE BACKGROUND LIVER TISSUES UNDERLYING CHRONIC LIVER DAMAGE CAUSED BY HEPATITIS VIRUS INFECTION. SEVERAL MAJOR MECHANISMS UNDERLIE THE GENETIC AND EPIGENETIC ABERRATIONS IN THE HEPATITIS VIRUS-INFECTED LIVER, SUCH AS THE GENERATION OF REACTIVE OXIDATIVE STRESS, ECTOPIC EXPRESSION OF DNA MUTATOR ENZYMES, AND DYSFUNCTION OF THE DNA REPAIR SYSTEM. IN ADDITION, DIRECT ONCOGENIC EFFECTS OF HEPATITIS VIRUS, REPRESENTED BY THE INTEGRATION OF HBV-DNA, ARE OBSERVED IN INFECTED HEPATOCYTES. ELUCIDATING THE WHOLE PICTURE OF GENETIC AND EPIGENETIC ALTERATIONS, AS WELL AS THE MECHANISMS OF TUMORIGENESIS, WILL FACILITATE THE DEVELOPMENT OF EFFICIENT TREATMENT AND PREVENTION STRATEGIES FOR HEPATITIS VIRUS-ASSOCIATED HCC. 2017