1 6381 144 THE ROLE OF ONCOGENIC DNA VIRUSES IN PENILE CANCER DEVELOPMENT. PENILE CANCER IS A RELATIVELY RARE NEOPLASIA IN DEVELOPED COUNTRIES, WITH SIGNIFICANT MORBIDITY AND MORTALITY IN DEVELOPING COUNTRIES. PENILE CANCER CAN BE SUBDIVIDED INTO HUMAN PAPILLOMAVIRUS (HPV)-POSITIVE AND HPV-NEGATIVE CASES. WORLDWIDE, THE HPV PREVALENCE IN PENILE CANCER SAMPLES IS AROUND 50%, AND HPV16 IS THE MOST PREVALENT GENOTYPE. ALTHOUGH HPV IS AN IMPORTANT FACTOR FOR CANCER DEVELOPMENT, OTHER ONCOGENIC FACTORS MAY BE ASSOCIATED WITH CARCINOGENESIS. SOME OF THESE FACTORS CAN BE INFECTIOUS, SUCH AS THE EPSTEIN-BARR VIRUS (EBV), AS WELL AS THE MERKEL CELL POLYOMAVIRUS (MCPYV). THE PREVALENCE RATES OF NEARLY 50% FOR BOTH HPV AND EBV INFECTIONS INDICATE AN IMPORTANT ROLE OF THESE VIRUSES IN PENILE TISSUE MALIGNANCY, REINFORCING THE IDEA OF A MULTIFACTORIAL ETIOLOGY OF THE DISEASE. ALTHOUGH THE HPV ROLE IS BETTER UNDERSTOOD, EBV IS THOUGHT TO FACILITATE PERSISTENCE, INTEGRATION, AND MUTATIONS. RECENT STUDIES ON THE MERKEL CELL POLYOMAVIRUS HAVE NOT SHOWN A RELEVANT PREVALENCE IN PENILE CANCER SAMPLES, BUT ITS PRESENCE INDICATES THE OPPORTUNISTIC INFECTIOUS POTENTIAL OF THIS VIRUS. REGARDING HPV-NEGATIVE CASES, THE LITERATURE SUGGESTS A LINK WITH YOUNGER AGE AND EPIGENETIC ALTERATIONS, MAINLY THROUGH THE P16INK4A PATHWAY. RECENTLY, SEVERAL BIOMARKERS THAT MIGHT ACT AS PROGNOSTIC TOOLS (E.G., KI-67, SQUAMOUS CELL CARCINOMA ANTIGEN, AMONG OTHERS) HAVE BEEN PROPOSED, BUT THE RESULTS REMAIN CONTROVERSIAL. IN ADDITION, OTHER RISK FACTORS HAVE ALSO BEEN ASSOCIATED WITH PENILE CARCINOGENESIS, SUCH AS THE PRESENCE OF PHIMOSIS, NONCIRCUMCISION, CHRONIC INFLAMMATION, AND NUMBER OF SEXUAL PARTNERS. FURTHER STUDIES ARE NEEDED TO DEVELOP TOOLS FOR EARLY DETECTION AND EPIDEMIOLOGICAL SURVEILLANCE OF PENILE CANCER. 2019 2 4430 43 MOLECULAR BIOLOGY OF ONCOGENIC INFLAMMATORY PROCESSES. I. NON-ONCOGENIC AND ONCOGENIC PATHOGENS, INTRINSIC INFLAMMATORY REACTIONS WITHOUT PATHOGENS, AND MICRORNA/DNA INTERACTIONS (REVIEW). IN SOME INFLAMMASOMES TUMOR CELLS ARE GENERATED. THE INTERNAL ENVIRONMENT OF THE INFLAMMASOME IS CONDUCIVE TO THE INDUCTION OF MALIGNANT TRANSFORMATION. EPIGENETIC CHANGES INITIATE THIS PROCESS. THE SUBVERTED STROMAL CONNECTIVE TISSUE CELLS ACT TO PROMOTE AND SUSTAIN THE PROCESS OF MALIGNANT TRANS-FORMATION. IN ITS EARLY STAGES, THE PREMALIGNANT CELLS DEPEND ON PARACRINE CIRCUITRIES FOR THE RECEPTION OF GROWTH FACTORS. THE LIGANDS ARE DERIVED FROM THE CONNECTIVE TISSUE, AND THE RECEPTORS ARE EXPRESSED ON THE RECIPIENT PREMALIGNANT CELLS. THE INITIAL EVENTS ARE NOT A DIRECT ATTACK ON THE PROTO-ONCOGENES, AND THUS IT MAY BE ENTIRELY REVERSIBLE. EPIGENETIC PROCESSES OF HYPERMETHYLATION OF THE GENES AT THE PROMOTERS OF TUMOR SUPPRESSOR GENES (TO SILENCE THEM), AND DEACETYLATION OF THE HISTONES AIMED AT THE PROMOTERS OF PROTO-ONCOGENES (TO ACTIVATE THEM) ARE ON-GOING. A LARGE NUMBER OF SHORT RNA SEQUENCES (INTERFERING, MICRO-, SHORT HAIRPIN, NON-CODING RNAS) SILENCE TUMOR SUPPRESSOR GENES, BY NEUTRALIZING THEIR MRNAS. IN A SERIAL SEQUENCE ONCOGENES UNDERGO AMPLIFICATIONS, POINT-MUTATIONS, TRANSLOCATIONS AND FUSIONS. IN ITS EARLIEST STAGE, THE PROCESS IS REVERSIBLE BY DEMETHYLATION OF THE SILENCED SUPPRESSOR GENE PROMOTERS (TO REACTIVATE THEM), OR RE-ACETYLATION OF THE HISTONES OF THE ONCOGENE PROMOTERS, THUS DE-ACTIVATING THEM. THE EXTERNAL ADMINISTRATION OF HISTONE DEACETYLASE INHIBITORS USUALLY LEADS TO THE RESTORATION OF HISTONE ACETYLATION. IN TIME, THE UNCORRECTED PROCESSES SOLIDIFY INTO CONSTITUTIVE AND IRREVERSIBLE GENE MUTATIONS. SOME OF THE PATHOGENS INDUCING INFLAMMATIONS WITH CONSQUENTIAL MALIGNANT TRANSFORMATION CONTAIN ONCOGENIC GENE SEQUENCES (PAPILLOMA VIRUSES, EPSTEIN-BARR VIRUS, KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS, HEPATITIS B AND C VIRUSES, MERKEL CELL POLYOMA VIRUS, HELICOBACTER PYLORI, ENTEROTOXIGENIC BACTEROIDES FRAGILIS). THESE INDUCED MALIGNANCIES MAY BE MULTIFOCAL. OTHER PATHOGENS ARE DEVOID OF ANY KNOWN ONCOGENIC GENOMIC SEQUENCES (MYCOPLASMA VAV-CARCINOGENESIS, CHLAMYDIA MALT-LYMPHOMA GENESIS). IN THESE CASES THE HOST'S INFLAMMATORY REACTIONS INDUCE THE MALIGNANT TRANSFORMATION IN SERIAL SEQUENCES OF GENE ALTERATIONS INITIATED BY HYPOXIA AND REACTIVE OXYGEN AND NITROGEN SPECIES GENERATION. CARCINOGENIC INTRINSIC INFLAMMATORY PROCESSES ENDOGENOUSLY INITIATED WITHOUT A PATHOGEN ARE RECOGNIZED. CHRONIC INFLAMMATORY PROCESSES SIGNAL THE RNA/DNA COMPLEX. IN RESPONSE, THE DNA MAY REVERT INTO ITS ANCIENT PRIMORDIAL 'IMMORTAL' FORMAT, WHICH THE CLINICS RECOGNIZE AS 'ONCOGENESIS'. THE DNA REMAINS THE ULTIMATE MASTER OF BIOENGINEERING IN ORDER TO SUSTAIN LIFE. A DISCUSSION ON THE MOST VERSATILE AND RESISTANT PRIMORDIAL RNA/DNA COMPLEX AND THE PRE-, PROTO-, AND UNICELLULAR WORLD IN WHICH THEY CO-EXISTED IS INCLUDED. 2012 3 1432 38 DIFFERENTIAL GENE HYPERMETHYLATION IN GENITAL LICHEN SCLEROSUS AND CANCER: A COMPARATIVE STUDY. AIMS: LICHEN SCLEROSUS (LS) IS A CHRONIC INFLAMMATORY DISEASE OF THE GENITAL SKIN OF UNKNOWN AETIOLOGY. THE ROLE OF LS IN PENILE SQUAMOUS CELL CARCINOGENESIS IS NOT WELL CHARACTERIZED. HPV HAS BEEN IMPLICATED IN BOTH, AS HAVE EPIGENETIC CHANGES. THE PRESENCE OF HPV AND HYPERMETHYLATION OF THE MGMT, P16, RASSF1, RASSF2, TSLC1 AND TSP1 GENES WERE STUDIED IN PENILE LS; MGMT, RASSF2 AND TSLC1 HYPERMETHYLATION IN PENILE CANCER AND TSLC1 HYPERMETHYLATION IN VULVAR LS AND CANCER EXTENDS PREVIOUS RESULTS REPORTED BY OUR GROUP. METHODS AND RESULTS: THIRTY-SEVEN HPV GENOTYPES AND HYPERMETHYLATION WERE EVALUATED BY PCR/REVERSE-LINE-BLOT AND METHYLATION-SPECIFIC PCR RESPECTIVELY, IN 27 PREPUTIAL LS, 24 PENILE SCC, 30 VULVAR SCC, 21 VULVAR LS AND 22 NORMAL SKIN CASES. HPV66 WAS PRESENT IN 3.7% OF PENILE LS CASES, AND P16 AND RASSF2 HYPERMETHYLATION WERE MORE FREQUENT IN PENILE CANCER THAN IN PENILE LS. P16, RASSF1, RASSF2 AND TSP1 HYPERMETHYLATION WERE SIMILAR IN PENILE AND VULVAR LS. CONCLUSIONS: GENE HYPERMETHYLATION IS A COMMON EVENT IN PENILE LS, AND OCCURS APPROXIMATELY AS FREQUENTLY AS IN VULVAR LS. CERTAIN GENES CAN BE HYPERMETHYLATED AS AN EARLY OR LATE EVENT IN LS OR CANCER, RESPECTIVELY. THIS SUGGESTS A POSSIBLE SEQUENTIAL ROLE FOR THESE ALTERATIONS IN THE TRANSITION FROM BENIGN TO MALIGNANT LESIONS. 2013 4 3597 53 IMPLICATIONS OF VIRAL INFECTIONS AND ONCOGENESIS IN UTERINE CERVICAL CARCINOMA ETIOLOGY AND PATHOGENESIS. BACKGROUND: UTERINE CERVICAL CARCINOMA (UCC) IS THE MOST PREVALENT GYNECOLOGICAL MALIGNANCY GLOBALLY, WITH A RISING INCIDENCE IN RECENT YEARS. ACCUMULATING EVIDENCE INDICATES THAT SPECIFIC VIRAL INFECTIONS, INCLUDING HUMAN PAPILLOMAVIRUS (HPV), EPSTEIN-BARR VIRUS (EBV), HEPATITIS B AND C VIRUSES (HBV AND HCV), AND HUMAN HERPESVIRUS (HHV), MAY CONTRIBUTE TO UCC DEVELOPMENT AND PROGRESSION. UNDERSTANDING THE COMPLEX INTERPLAY BETWEEN VIRAL INFECTIONS AND UCC RISK IS CRUCIAL FOR DEVELOPING NOVEL PREVENTATIVE AND THERAPEUTIC INTERVENTIONS. METHODS: THIS COMPREHENSIVE REVIEW INVESTIGATES THE ASSOCIATION BETWEEN VIRAL INFECTIONS AND UCC RISK BY EXAMINING THE ROLES OF VARIOUS VIRAL PATHOGENS IN UCC ETIOLOGY AND PATHOGENESIS, AND POSSIBLE MOLECULAR MECHANISMS. ADDITIONALLY, WE EVALUATE CURRENT DIAGNOSTIC METHODS AND POTENTIAL THERAPEUTIC STRATEGIES TARGETING VIRAL INFECTIONS FOR UCC PREVENTION OR TREATMENT. RESULTS: THE PREVENTION OF UCC HAS BEEN SIGNIFICANTLY ADVANCED BY THE EMERGENCE OF SELF-SAMPLING FOR HPV TESTING AS A CRUCIAL TOOL, ALLOWING FOR EARLY DETECTION AND INTERVENTION. HOWEVER, AN ESSENTIAL CHALLENGE IN UCC PREVENTION LIES IN UNDERSTANDING HOW HPV AND OTHER VIRAL COINFECTIONS, INCLUDING EBV, HBV, HCV, HHV, HIV, OR THEIR CONCURRENT PRESENCE, MAY POTENTIALLY CONTRIBUTE TO UCC DEVELOPMENT. THE MOLECULAR MECHANISMS IMPLICATED IN THE ASSOCIATION BETWEEN VIRAL INFECTIONS AND CERVICAL CANCER DEVELOPMENT INCLUDE: (1) INTERFERENCE OF VIRAL ONCOGENES WITH CELLULAR REGULATORY PROTEINS, RESULTING IN UNCONTROLLED CELL PROLIFERATION AND MALIGNANT TRANSFORMATION; (2) INACTIVATION OF TUMOR SUPPRESSOR GENES BY VIRAL PROTEINS; (3) EVASION OF HOST IMMUNE RESPONSES BY VIRUSES; (4) INDUCTION OF A PERSISTENT INFLAMMATORY RESPONSE, CONTRIBUTING TO A TUMOR-PROMOTING MICROENVIRONMENT; (5) EPIGENETIC MODIFICATIONS THAT LEAD TO ABERRANT GENE EXPRESSION; (6) STIMULATION OF ANGIOGENESIS BY VIRUSES; AND (7) ACTIVATION OF TELOMERASE BY VIRAL PROTEINS, LEADING TO CELLULAR IMMORTALIZATION. ADDITIONALLY, VIRAL COINFECTIONS CAN ALSO ENHANCE ONCOGENIC POTENTIAL THROUGH SYNERGISTIC INTERACTIONS BETWEEN VIRAL ONCOPROTEINS, EMPLOY IMMUNE EVASION STRATEGIES, CONTRIBUTE TO CHRONIC INFLAMMATION, MODULATE HOST CELLULAR SIGNALING PATHWAYS, AND INDUCE EPIGENETIC ALTERATIONS, ULTIMATELY LEADING TO CERVICAL CARCINOGENESIS. CONCLUSION: RECOGNIZING THE IMPLICATIONS OF VIRAL ONCOGENES IN UCC ETIOLOGY AND PATHOGENESIS IS VITAL FOR ADDRESSING THE ESCALATING BURDEN OF UCC. DEVELOPING INNOVATIVE PREVENTATIVE AND THERAPEUTIC INTERVENTIONS REQUIRES A THOROUGH UNDERSTANDING OF THE INTRICATE RELATIONSHIP BETWEEN VIRAL INFECTIONS AND UCC RISK. 2023 5 4905 39 P16INK4A HYPERMETHYLATION IS ASSOCIATED WITH HEPATITIS VIRUS INFECTION, AGE, AND GENDER IN HEPATOCELLULAR CARCINOMA. PURPOSE: THE TUMOR SUPPRESSOR GENE P16INK4A IS MAINLY INACTIVATED BY AN EPIGENETIC CHANGE INVOLVING PROMOTER HYPERMETHYLATION IN HEPATOCARCINOGENESIS. THE POSSIBLE CLINICAL IMPACT OF P16INK4A METHYLATION AND THE POTENTIAL RISK FACTORS FOR THIS EPIGENETIC ALTERATION HAVE NOT BEEN THOROUGHLY INVESTIGATED. EXPERIMENTAL DESIGN: WE STUDIED THE METHYLATION STATUS AND MRNA AND PROTEIN EXPRESSION OF P16INK4A IN 50 HEPATOCELLULAR CARCINOMAS AND CORRESPONDING NONNEOPLASTIC LIVER LESIONS USING METHYLATION-SPECIFIC PCR, REVERSE TRANSCRIPTION-PCR, AND IMMUNOHISTOCHEMICAL TECHNIQUES. RESULTS: P16INK4A HYPERMETHYLATION WAS OBSERVED IN 58% (29 OF 50) OF THE HEPATOCELLULAR CARCINOMAS AND 16% (6 OF 38) OF THE CORRESPONDING CHRONIC HEPATITIS AND CIRRHOSIS TISSUE SAMPLES. P16INK4A METHYLATION WAS SIGNIFICANTLY ASSOCIATED WITH MRNA AND PROTEIN EXPRESSION (P <0.001 AND P=0.003, RESPECTIVELY). ALL OF THE P16INK4A-METHYLATED TUMORS WERE POSITIVE FOR HEPATITIS B VIRUS OR HEPATITIS C VIRUS MARKERS, BUT NONE OF THE VIRUS-NEGATIVE TUMORS EXHIBITED P16INK4A METHYLATION (P=0.006). THE FREQUENCY OF P16INK4A HYPERMETHYLATION TENDED TO BE HIGHER IN HEPATITIS C VIRUS-RELATED TUMORS (23 OF 32, 72%) THAN IN HEPATITIS B VIRUS-RELATED TUMORS (6 OF 13, 46%; P=0.1). ABERRANT METHYLATION OF P16INK4A WAS ALSO RELATED SIGNIFICANTLY TO INCREASING AGE, FEMALE GENDER, AND NORMAL LEVELS OF SERUM PIVKA-II (P=0.02, 0.04, AND 0.04, RESPECTIVELY). NO STATISTICALLY SIGNIFICANT DIFFERENCE IN SURVIVAL WAS OBSERVED BETWEEN PATIENTS WITH P16INK4A HYPERMETHYLATION AND THOSE WITHOUT. CONCLUSIONS: OUR OBSERVATIONS SUGGEST THAT P16INK4A HYPERMETHYLATION MAY CONTRIBUTE TO HEPATOCARCINOGENESIS FROM AN EARLY STAGE AND THAT MULTIPLE RISK FACTORS, SUCH AS VIRAL INFECTIONS, AGE, AND GENDER, MAY BE ASSOCIATED WITH P16INK4A HYPERMETHYLATION IN HEPATOCARCINOGENESIS. 2004 6 6486 40 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 4815 39 OCCULT HEPATITIS B INFECTION AND HEPATOCELLULAR CARCINOMA: EPIDEMIOLOGY, VIROLOGY, HEPATOCARCINOGENESIS AND CLINICAL SIGNIFICANCE. OCCULT HEPATITIS B INFECTION (OBI) REFERS TO A CONDITION WHERE REPLICATION-COMPETENT HBV DNA IS PRESENT IN THE LIVER, WITH OR WITHOUT HBV DNA IN THE BLOOD, IN INDIVIDUALS WITH SERUM HBSAG NEGATIVITY ASSESSED BY CURRENTLY AVAILABLE ASSAYS. THE EPISOMAL COVALENTLY CLOSED CIRCULAR DNA (CCCDNA) IN OBI IS IN A LOW REPLICATIVE STATE. VIRAL GENE EXPRESSION IS MEDIATED BY EPIGENETIC CONTROL OF HBV TRANSCRIPTION, INCLUDING THE HBV CPG ISLAND METHYLATION PATHWAY AND POST-TRANSLATIONAL MODIFICATION OF CCCDNA-BOUND HISTONE, WITH A DIFFERENT PATTERN FROM PATIENTS WITH CHRONIC HBV INFECTION. THE PREVALENCE OF OBI VARIES TREMENDOUSLY ACROSS PATIENT POPULATIONS OWING TO NUMEROUS FACTORS, SUCH AS GEOGRAPHIC LOCATION, ASSAY CHARACTERISTICS, HOST IMMUNE RESPONSE, COINFECTION WITH OTHER VIRUSES, AND VACCINATION STATUS. APART FROM THE RISK OF VIRAL REACTIVATION UPON IMMUNOSUPPRESSION AND THE RISK OF TRANSMISSION OF HBV, OBI HAS BEEN IMPLICATED IN HEPATOCELLULAR CARCINOMA (HCC) DEVELOPMENT IN PATIENTS WITH CHRONIC HCV INFECTION, THOSE WITH CRYPTOGENIC OR KNOWN LIVER DISEASE, AND IN PATIENTS WITH HBSAG SEROCLEARANCE AFTER CHRONIC HBV INFECTION. AN INCREASING NUMBER OF PROSPECTIVE STUDIES AND META-ANALYSES HAVE REPORTED A HIGHER INCIDENCE OF HCC IN PATIENTS WITH HCV AND OBI, AS WELL AS MORE ADVANCED TUMOUR HISTOLOGICAL GRADES AND EARLIER AGE OF HCC DIAGNOSIS, COMPARED WITH PATIENTS WITHOUT OBI. THE PROPOSED PATHOGENETIC MECHANISMS OF OBI-RELATED HCC INCLUDE THE INFLUENCE OF HBV DNA INTEGRATION ON THE HEPATOCYTE CELL CYCLE, THE PRODUCTION OF PRO-ONCOGENIC PROTEINS (HBX PROTEIN AND MUTATED SURFACE PROTEINS), AND PERSISTENT LOW-GRADE NECROINFLAMMATION (CONTRIBUTING TO THE DEVELOPMENT OF FIBROSIS AND CIRRHOSIS). THERE REMAIN UNCERTAINTIES ABOUT EXACTLY HOW, AND IN WHAT ORDER, THESE MECHANISMS DRIVE THE DEVELOPMENT OF TUMOURS IN PATIENTS WITH OBI. 2020 8 5181 31 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 9 3232 24 HELICOBACTER PYLORI-INDUCED SIGNALING PATHWAYS CONTRIBUTE TO INTESTINAL METAPLASIA AND GASTRIC CARCINOGENESIS. HELICOBACTER PYLORI (H. PYLORI) INDUCES CHRONIC GASTRIC INFLAMMATION, ATROPHIC GASTRITIS, INTESTINAL METAPLASIA, AND CANCER. ALTHOUGH THE RISK OF GASTRIC CANCER INCREASES EXPONENTIALLY WITH THE EXTENT OF ATROPHIC GASTRITIS, THE PRECISE MECHANISMS OF GASTRIC CARCINOGENESIS HAVE NOT BEEN FULLY ELUCIDATED. H. PYLORI INDUCES GENETIC AND EPIGENETIC CHANGES IN GASTRIC EPITHELIAL CELLS THROUGH ACTIVATING INTRACELLULAR SIGNALING PATHWAYS IN A CAGPAI-DEPENDENT MANNER. H. PYLORI EVENTUALLY INDUCES GASTRIC CANCER WITH CHROMOSOMAL INSTABILITY (CIN) OR MICROSATELLITE INSTABILITY (MSI), WHICH ARE CLASSIFIED AS TWO MAJOR SUBTYPES OF GASTRIC CANCER. ELUCIDATION OF THE PRECISE MECHANISMS OF GASTRIC CARCINOGENESIS WILL ALSO BE IMPORTANT FOR CANCER THERAPY. 2015 10 3671 45 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 11 1031 43 CIRCULATING TUMOR DNA DETECTION AND ITS APPLICATION STATUS IN GASTRIC CANCER: A NARRATIVE REVIEW. CIRCULATING TUMOR DNA (CTDNA) IS THE SMALL GENOMIC FRAGMENT RELEASED BY TUMOR CELLS INTO THE CIRCULATING SYSTEM, WHICH CARRIES THE GENE VARIATION FEATURES, SUCH AS MUTATION, INSERTION, DELETION, REARRANGEMENT, COPY NUMBER VARIATION (CNV) AND METHYLATION, RENDERING IT AN IMPORTANT BIOMARKER. IT CAN BE USED NOT ONLY TO DIAGNOSE CERTAIN TYPES OF SOLID TUMORS, BUT ALSO TO MONITOR THE THERAPEUTIC RESPONSE AND EXPLORE THE MINIMAL RESIDUAL DISEASE (MRD) AND RESISTANT MUTATION OF TARGETED THERAPY. THEREFORE, CTDNA DETECTION MAY BECOME THE PREFERRED NON-INVASIVE TUMOR SCREENING METHOD. FOR PATIENTS WHO CANNOT RECEIVE FURTHER GENE DETECTION DUE TO INSUFFICIENT OR RESTRICTED SAMPLE COLLECTION WITH THE DEFINED PATHOLOGICAL DIAGNOSIS, CTDNA DETECTION CAN BE CARRIED OUT TO DETERMINE THE GENE MUTATION TYPE, WITH NO NEED FOR REPEATED SAMPLING. GASTRIC CANCER (GC) IS A MALIGNANCY WITH EXTREMELY HIGH MORBIDITY AND MORTALITY, AND ITS GENESIS AND DEVELOPMENT ARE THE CONSEQUENCE OF INTERACTIONS OF MULTIPLE FACTORS, INCLUDING ENVIRONMENT, DIET, HEREDITY, HELICOBACTER PYLORI INFECTION, CHRONIC INFLAMMATORY INFILTRATION, AND PRECANCEROUS LESION. AS THE RESEARCH ON GC MOVES FORWARD, THE EXISTING RESEARCH MAINLY FOCUSES ON GENETIC AND EPIGENETIC CHANGES, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, NON-CODING RNA CHANGES, GENE MUTATION, GENE HETEROZYGOSITY LOSS AND MICROSATELLITE INSTABILITY. THIS PAPER AIMED TO SUMMARIZE THE CONTENTS OF CTDNA DETECTION, ITS APPLICATION STATUS IN GC AND CLINICAL SIGNIFICANCE. 2021 12 3271 39 HEPATOCELLULAR CARCINOMA RISK AFTER VIRAL RESPONSE IN HEPATITIS C VIRUS-ADVANCED FIBROSIS: WHO TO SCREEN AND FOR HOW LONG? HEPATITIS C VIRUS (HCV) CHRONIC INFECTION IS ASSOCIATED WITH FIBROSIS PROGRESSION, END-STAGE LIVER COMPLICATIONS AND HCC. NOT SURPRISINGLY, HCV INFECTION IS A LEADING CAUSE OF LIVER-RELATED MORBIDITY AND MORTALITY WORLDWIDE. AFTER SUSTAINED VIROLOGICAL RESPONSE (SVR), THE RISK OF DEVELOPING HEPATOCELLULAR CARCINOMA IS NOT COMPLETELY ELIMINATED IN PATIENTS WITH ESTABLISHED CIRRHOSIS OR WITH ADVANCED FIBROSIS. THEREFORE, LIFELONG SURVEILLANCE IS CURRENTLY RECOMMENDED. THIS STRATEGY IS LIKELY NOT UNIVERSALLY COST-EFFECTIVE AND HARMLESS, CONSIDERING THAT NOT ALL PATIENTS WITH ADVANCED FIBROSIS HAVE THE SAME RISK OF DEVELOPING HCC. FACTORS RELATED TO THE SEVERITY OF LIVER DISEASE AND ITS POTENTIAL TO IMPROVE AFTER SVR, THE MOLECULAR AND EPIGENETIC CHANGES THAT OCCUR DURING INFECTION AND OTHER ASSOCIATED COMORBIDITIES MIGHT ACCOUNT FOR DIFFERENT RISK LEVELS AND ARE LIKELY ESSENTIAL FOR IDENTIFYING PATIENTS WHO WOULD BENEFIT FROM SCREENING PROGRAMS AFTER SVR. EFFORTS TO DEVELOP PREDICTIVE MODELS AND RISK CALCULATORS, BIOMARKERS AND GENETIC PANELS AND EVEN DEEP LEARNING MODELS TO ESTIMATE THE INDIVIDUAL RISK OF HCC HAVE BEEN MADE IN THE DIRECT-ACTING ANTIVIRAL AGENTS ERA, WHEN THOUSANDS OF PATIENTS WITH ADVANCED FIBROSIS AND CIRRHOSIS HAVE REACHED SVR. THESE TOOLS COULD HELP TO IDENTIFY PATIENTS WITH VERY LOW HCC RISK IN WHOM SURVEILLANCE MIGHT NOT BE JUSTIFIED. IN THIS REVIEW, FACTORS AFFECTING THE PROBABILITY OF HCC DEVELOPMENT AFTER SVR, THE BENEFITS AND RISKS OF SURVEILLANCE, SUGGESTED STRATEGIES TO ESTIMATE INDIVIDUALIZED HCC RISK AND THE CURRENT EVIDENCE TO RECOMMEND LIFELONG SURVEILLANCE ARE DISCUSSED. 2021 13 4816 37 OCCULT HEPATITIS B VIRUS INFECTION: A COMPLEX ENTITY WITH RELEVANT CLINICAL IMPLICATIONS. OCCULT HEPATITIS B VIRUS (HBV) INFECTION IS A WORLD-WIDE ENTITY, FOLLOWING THE GEOGRAPHICAL DISTRIBUTION OF DETECTABLE HEPATITIS B. THIS ENTITY IS DEFINED AS THE PERSISTENCE OF VIRAL GENOMES IN THE LIVER TISSUE AND IN SOME INSTANCES ALSO IN THE SERUM, ASSOCIATED TO NEGATIVE HBV SURFACE ANTIGEN SEROLOGY. THE MOLECULAR BASIS OF THE OCCULT INFECTION IS RELATED TO THE LIFE CYCLE OF HBV, WHICH PRODUCES A COVALENTLY CLOSED CIRCULAR DNA THAT PERSISTS IN THE CELL NUCLEI AS AN EPISOME, AND SERVES AS A TEMPLATE FOR GENE TRANSCRIPTION. THE MECHANISM RESPONSIBLE FOR THE HBSAG NEGATIVE STATUS IN OCCULT HBV CARRIERS IS A STRONG SUPPRESSION OF VIRAL REPLICATION, PROBABLY DUE TO THE HOST'S IMMUNE RESPONSE, CO-INFECTION WITH OTHER INFECTIOUS AGENTS AND EPIGENETIC FACTORS. THERE IS EMERGING EVIDENCE OF THE POTENTIAL CLINICAL RELEVANCE OF OCCULT HBV INFECTION, SINCE THIS COULD BE INVOLVED IN OCCULT HBV TRANSMISSION THROUGH ORTHOTOPIC LIVER TRANSPLANT AND BLOOD TRANSFUSION, REACTIVATION OF HBV INFECTION DURING IMMUNOSUPPRESSION, IMPAIRING CHRONIC LIVER DISEASE OUTCOME AND ACTING AS A RISK FACTOR FOR HEPATOCELLULAR CARCINOMA. THEREFORE IT IS IMPORTANT TO BEAR IN MIND THIS ENTITY IN CRYPTOGENETIC LIVER DISEASES, HEPATITIS C VIRUS/HIV INFECTED PATIENTS AND IMMUNOSUPRESSED INDIVIDUALS. IT IS ALSO NECESSARY TO INCREASE OUR KNOWLEDGE IN THIS FASCINATING FIELD TO DEFINE BETTER STRATEGIES TO DIAGNOSE AND TREAT THIS INFECTION. 2011 14 1540 40 DNA METHYLATION IN GASTRIC CANCER, RELATED TO HELICOBACTER PYLORI AND EPSTEIN-BARR VIRUS. GASTRIC CANCER IS A LEADING CAUSE OF CANCER DEATH WORLDWIDE, AND SIGNIFICANT EFFORT HAS BEEN FOCUSED ON CLARIFYING THE PATHOLOGY OF GASTRIC CANCER. IN PARTICULAR, THE DEVELOPMENT OF GENOME-WIDE ANALYSIS TOOLS HAS ENABLED THE DETECTION OF GENETIC AND EPIGENETIC ALTERATIONS IN GASTRIC CANCER; FOR EXAMPLE, ABERRANT DNA METHYLATION IN GENE PROMOTER REGIONS IS THOUGHT TO PLAY A CRUCIAL ROLE IN GASTRIC CARCINOGENESIS. THE ETIOLOGICAL VIEWPOINT IS ALSO ESSENTIAL FOR THE STUDY OF GASTRIC CANCERS, AND TWO DISTINCT PATHOGENS, HELICOBACTER PYLORI (H. PYLORI) AND EPSTEIN-BARR VIRUS (EBV), ARE KNOWN TO PARTICIPATE IN GASTRIC CARCINOGENESIS. CHRONIC INFLAMMATION OF THE GASTRIC EPITHELIUM DUE TO H. PYLORI INFECTION INDUCES ABERRANT POLYCLONAL METHYLATION THAT MAY LEAD TO AN INCREASED RISK OF GASTRIC CANCER. IN ADDITION, EBV INFECTION IS KNOWN TO CAUSE EXTENSIVE METHYLATION, AND EBV-POSITIVE GASTRIC CANCERS DISPLAY A HIGH METHYLATION EPIGENOTYPE, IN WHICH ABERRANT METHYLATION EXTENDS TO NOT ONLY POLYCOMB REPRESSIVE COMPLEX (PRC)-TARGET GENES IN EMBRYONIC STEM CELLS BUT ALSO NON-PRC-TARGET GENES. HERE, WE REVIEW ABERRANT DNA METHYLATION IN GASTRIC CANCER AND THE ASSOCIATION BETWEEN METHYLATION AND INFECTION WITH H. PYLORI AND EBV. 2014 15 4984 33 PATHWAYS OF GASTRIC CARCINOGENESIS, HELICOBACTER PYLORI VIRULENCE AND INTERACTIONS WITH ANTIOXIDANT SYSTEMS, VITAMIN C AND PHYTOCHEMICALS. HELICOBACTER PYLORI IS A CLASS ONE CARCINOGEN WHICH CAUSES CHRONIC ATROPHIC GASTRITIS, GASTRIC INTESTINAL METAPLASIA, DYSPLASIA AND ADENOCARCINOMA. THE MECHANISMS BY WHICH H. PYLORI INTERACTS WITH OTHER RISK AND PROTECTIVE FACTORS, PARTICULARLY VITAMIN C IN GASTRIC CARCINOGENESIS ARE COMPLEX. GASTRIC CARCINOGENESIS INCLUDES METABOLIC, ENVIRONMENTAL, EPIGENETIC, GENOMIC, INFECTIVE, INFLAMMATORY AND ONCOGENIC PATHWAYS. THE MOLECULAR CLASSIFICATION OF GASTRIC CANCER SUBTYPES HAS REVOLUTIONIZED THE UNDERSTANDING OF GASTRIC CARCINOGENESIS. THIS INCLUDES THE TUMOUR MICROENVIRONMENT, GERMLINE MUTATIONS, AND THE ROLE OF HELICOBACTER PYLORI BACTERIA, EPSTEIN BARR VIRUS AND EPIGENETICS IN SOMATIC MUTATIONS. THERE IS EVIDENCE THAT ASCORBIC ACID, PHYTOCHEMICALS AND ENDOGENOUS ANTIOXIDANT SYSTEMS CAN MODIFY THE RISK OF GASTRIC CANCER. GASTRIC JUICE ASCORBATE LEVELS DEPEND ON DIETARY INTAKE OF ASCORBIC ACID BUT CAN ALSO BE DECREASED BY H. PYLORI INFECTION, H. PYLORI CAGA SECRETION, TOBACCO SMOKING, ACHLORHYDRIA AND CHRONIC ATROPHIC GASTRITIS. ASCORBIC ACID MAY BE PROTECTIVE AGAINST GASTRIC CANCER BY ITS ANTIOXIDANT EFFECT IN GASTRIC CYTOPROTECTION, REGENERATING ACTIVE VITAMIN E AND GLUTATHIONE, INHIBITING ENDOGENOUS N-NITROSATION, REDUCING TOXIC EFFECTS OF INGESTED NITROSODIMETHYLAMINES AND HETEROCYCLIC AMINES, AND PREVENTING H. PYLORI INFECTION. THE EFFECTIVENESS OF SUCH CYTOPROTECTION IS RELATED TO H. PYLORI STRAIN VIRULENCE, PARTICULARLY CAGA EXPRESSION. THE ROLE OF VITAMIN C IN EPIGENETIC REPROGRAMMING IN GASTRIC CANCER IS STILL EVOLVING. OTHER FACTORS IN CONJUNCTION WITH VITAMIN C ALSO PLAY A ROLE IN GASTRIC CARCINOGENESIS. ERADICATION OF H. PYLORI MAY LEAD TO RECOVERY OF VITAMIN C SECRETION BY GASTRIC EPITHELIUM AND ENABLE REGRESSION OF PREMALIGNANT GASTRIC LESIONS, THEREBY INTERRUPTING THE CORREA CASCADE OF GASTRIC CARCINOGENESIS. 2020 16 3229 35 HELICOBACTER PYLORI-INDUCED GASTRIC INFLAMMATION AND GASTRIC CANCER. HELICOBACTER PYLORI (H. PYLORI) INFECT OVER HALF OF THE WORLD'S POPULATION. THE PREVALENCE OF H. PYLORI INFECTION AND THE PREDOMINANT GENOTYPE OF H. PYLORI VIRULENCE FACTORS VARY CONSIDERABLY ACROSS DIFFERENT GEOGRAPHICAL REGIONS. H. PYLORI COULD UNIQUELY PERSIST FOR DECADES IN THE HARSH STOMACH ENVIRONMENT, WHERE IT DAMAGES THE GASTRIC MUCOSA AND CHANGES THE PATTERN OF GASTRIC HORMONE RELEASE, THEREBY AFFECTS GASTRIC PHYSIOLOGY. BY UTILIZING VARIOUS VIRULENCE FACTORS, H. PYLORI TARGETS DIFFERENT CELLULAR PROTEINS TO MODULATE THE HOST INFLAMMATORY RESPONSE AND INITIATE MULTIPLE "HITS" ON THE GASTRIC MUCOSA, RESULTING IN CHRONIC GASTRITIS AND PEPTIC ULCERATION. AMONG THE LONG-TERM CONSEQUENCES OF H. PYLORI INFECTION IS GASTRIC MALIGNANCIES, PARTICULARLY GASTRIC CANCER (GC) AND GASTRIC MUCOSA-ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMA. AS SUCH, H. PYLORI HAS BEEN RECOGNIZED AS A CLASS I CARCINOGEN BY THE INTERNATIONAL AGENCY FOR RESEARCH ON CANCER. DESPITE A CLOSE CAUSAL LINK BETWEEN H. PYLORI INFECTION AND THE DEVELOPMENT OF GASTRIC MALIGNANCIES, THE PRECISE MECHANISMS INVOLVED IN THIS PROCESS ARE STILL OBSCURE. STUDIES OVER THE PAST TWO DECADES HAVE REVEALED THAT H. PYLORI EXERT ONCOGENIC EFFECTS ON GASTRIC MUCOSA THROUGH A COMPLEX INTERACTION BETWEEN BACTERIAL FACTORS, HOST FACTORS, AND ENVIRONMENTAL FACTORS. NUMEROUS SIGNALING PATHWAYS CAN BE ACTIVATED BY H. PYLORI. IN THIS REVIEW, WE AIM TO ELABORATE ON THE RECENT DEVELOPMENTS IN THE PATHOPHYSIOLOGICAL MECHANISMS OF H. PYLORI-INDUCED GASTRIC INFLAMMATION AND GASTRIC CANCER. 2014 17 4960 35 PATHOGENESIS OF PRE-NEOPLASTIC LESIONS OF THE STOMACH: TARGETS FOR PREVENTION. GASTRIC ATROPHY AND INTESTINAL METAPLASIA ARE GENERALLY CONSIDERED TO BE PRECANCEROUS LESIONS OF THE STOMACH. CHRONIC HELICOBACTER PYLORI INFECTION IS ONE THE MOST IMPORTANT FACTORS IN THE DEVELOPMENT OF THESE PRE-MALIGNANT GASTRIC LESIONS. IN ADDITION TO BACTERIAL FACTORS, POLYMORPHISMS IN THE CYTOKINE GENES OF THE HOST THAT MODULATE INFLAMMATORY RESPONSES ARE FOUND TO HAVE A SYNERGISTIC EFFECT IN THE DEVELOPMENT OF GASTRIC CANCER AS WELL AS PRE-NEOPLASTIC LESIONS. RECENTLY, INAPPROPRIATE ACTIVATION OF THE INTESTINE-SPECIFIC TRANSCRIPTION FACTOR LIKE THE HOMEOBOX GENE COMPLEX CDX1 AND CDX2 ARE FOUND TO BE AN IMPORTANT CONTRIBUTING FACTOR IN THE INDUCTION OF INTESTINAL METAPLASIA IN THE STOMACH. ABERRANT EXPRESSION OF CYCLOOXYGENASE-2 AND EPIGENETIC CHANGES ARE ALSO FREQUENTLY DETECTED IN PRE-NEOPLASTIC GASTRIC LESIONS. ONE OF THE MOST IMPORTANT QUESTIONS RELATING TO THESE PRE-NEOPLASTIC GASTRIC LESIONS IS THAT WHETHER H. PYLORI ERADICATION COULD REVERSE THESE CHANGES. HOWEVER, MOST CONTROLLED STUDIES SHOWED NO OR JUST MODEST IMPROVEMENT IN INTESTINAL METAPLASIA AFTER H. PYLORI ERADICATION. FURTHER STUDIES SHOULD EVALUATE THE ROLE OF OTHER CHEMOPREVENTIVE AGENTS, PARTICULARLY CYCLOOXYGENASE-2 INHIBITOR, ON REGRESSION OF PRE-NEOPLASTIC LESIONS. 2004 18 1057 36 CLINICAL MANIFESTATIONS AND EPIGENETIC REGULATION OF ORAL HERPESVIRUS INFECTIONS. THE ORAL CAVITY IS OFTEN THE FIRST SITE WHERE VIRUSES INTERACT WITH THE HUMAN BODY. THE ORAL EPITHELIUM IS A MAJOR SITE OF VIRAL ENTRY, REPLICATION AND SPREAD TO OTHER CELL TYPES, WHERE CHRONIC INFECTION CAN BE ESTABLISHED. IN ADDITION, SALIVA HAS BEEN SHOWN AS A PRIMARY ROUTE OF PERSON-TO-PERSON TRANSMISSION FOR MANY VIRUSES. FROM A CLINICAL PERSPECTIVE, VIRAL INFECTION CAN LEAD TO SEVERAL ORAL MANIFESTATIONS, RANGING FROM COMMON INTRAORAL LESIONS TO TUMORS. DESPITE THE CLINICAL AND BIOLOGICAL RELEVANCE OF INITIAL ORAL INFECTION, LITTLE IS KNOWN ABOUT THE MECHANISM OF REGULATION OF THE VIRAL LIFE CYCLE IN THE ORAL CAVITY. SEVERAL VIRUSES UTILIZE HOST EPIGENETIC MACHINERY TO PROMOTE THEIR OWN LIFE CYCLE. IMPORTANTLY, VIRAL HIJACKING OF HOST CHROMATIN-MODIFYING ENZYMES CAN ALSO LEAD TO THE DYSREGULATION OF HOST FACTORS AND IN THE CASE OF ONCOGENIC VIRUSES MAY ULTIMATELY PLAY A ROLE IN PROMOTING TUMORIGENESIS. GIVEN THE KNOWN ROLES OF EPIGENETIC REGULATION OF VIRAL INFECTION, EPIGENETIC-TARGETED ANTIVIRAL THERAPY HAS BEEN RECENTLY EXPLORED AS A THERAPEUTIC OPTION FOR CHRONIC VIRAL INFECTION. IN THIS REVIEW, WE HIGHLIGHT THREE HERPESVIRUSES WITH KNOWN ROLES IN ORAL INFECTION, INCLUDING HERPES SIMPLEX VIRUS TYPE 1, EPSTEIN-BARR VIRUS AND KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS. WE FOCUS ON THE RESPECTIVE ORAL CLINICAL MANIFESTATIONS OF THESE VIRUSES AND THEIR EPIGENETIC REGULATION, WITH A SPECIFIC EMPHASIS ON THE VIRAL LIFE CYCLE IN THE ORAL EPITHELIUM. 2021 19 2662 48 EPSTEIN-BARR VIRUS AND MULTIPLE SCLEROSIS: A CONVOLUTED INTERACTION AND THE OPPORTUNITY TO UNRAVEL PREDICTIVE BIOMARKERS. SINCE THE EARLY 1980S, EPSTEIN-BARR VIRUS (EBV) INFECTION HAS BEEN DESCRIBED AS ONE OF THE MAIN RISK FACTORS FOR DEVELOPING MULTIPLE SCLEROSIS (MS), AND RECENTLY, NEW EPIDEMIOLOGICAL EVIDENCE HAS REINFORCED THIS PREMISE. EBV SEROCONVERSION PRECEDES ALMOST 99% OF THE NEW CASES OF MS AND LIKELY PREDATES THE FIRST CLINICAL SYMPTOMS. THE MOLECULAR MECHANISMS OF THIS ASSOCIATION ARE COMPLEX AND MAY INVOLVE DIFFERENT IMMUNOLOGICAL ROUTES, PERHAPS ALL RUNNING IN PARALLEL (I.E., MOLECULAR MIMICRY, THE BYSTANDER DAMAGE THEORY, ABNORMAL CYTOKINE NETWORKS, AND COINFECTION OF EBV WITH RETROVIRUSES, AMONG OTHERS). HOWEVER, DESPITE THE LARGE AMOUNT OF EVIDENCE AVAILABLE ON THESE TOPICS, THE ULTIMATE ROLE OF EBV IN THE PATHOGENESIS OF MS IS NOT FULLY UNDERSTOOD. FOR INSTANCE, IT IS UNCLEAR WHY AFTER EBV INFECTION SOME INDIVIDUALS DEVELOP MS WHILE OTHERS EVOLVE TO LYMPHOPROLIFERATIVE DISORDERS OR SYSTEMIC AUTOIMMUNE DISEASES. IN THIS REGARD, RECENT STUDIES SUGGEST THAT THE VIRUS MAY EXERT EPIGENETIC CONTROL OVER MS SUSCEPTIBILITY GENES BY MEANS OF SPECIFIC VIRULENCE FACTORS. SUCH GENETIC MANIPULATION HAS BEEN DESCRIBED IN VIRALLY-INFECTED MEMORY B CELLS FROM PATIENTS WITH MS AND ARE THOUGHT TO BE THE MAIN SOURCE OF AUTOREACTIVE IMMUNE RESPONSES. YET, THE ROLE OF EBV INFECTION IN THE NATURAL HISTORY OF MS AND IN THE INITIATION OF NEURODEGENERATION IS EVEN LESS CLEAR. IN THIS NARRATIVE REVIEW, WE WILL DISCUSS THE AVAILABLE EVIDENCE ON THESE TOPICS AND THE POSSIBILITY OF HARNESSING SUCH IMMUNOLOGICAL ALTERATIONS TO UNCOVER PREDICTIVE BIOMARKERS FOR THE ONSET OF MS AND PERHAPS FACILITATE PROGNOSTICATION OF THE CLINICAL COURSE. 2023 20 4903 25 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