1 1617 132 DNA METHYLTRANSFERASE EXPRESSION AND DNA METHYLATION IN HUMAN HEPATOCELLULAR CARCINOMA AND THEIR CLINICOPATHOLOGICAL CORRELATION. ABERRANT DNA METHYLATION ON CPG ISLANDS IS ONE OF THE MOST CONSISTENT EPIGENETIC CHANGES IN HUMAN CANCERS, AND THE METHYLATION PROCESS IS CATALYZED BY DNA METHYLTRANSFERASE (DNMT). WE EVALUATED I) THE MRNA LEVELS OF THREE DNMTS; DNMT1, DNMT3A AND DNMT3B, IN 25 HEPATOCELLULAR CARCINOMAS (HCCS), IN THEIR CORRESPONDING NON-CANCEROUS LIVER TISSUES AND IN 7 NORMAL LIVERS BY USING REAL-TIME REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION; II) NUCLEAR EXPRESSION OF DNMT1 AND DNMT3A PROTEINS IN THE HCCS BY IMMUNOHISTOCHEMISTRY, III) THE METHYLATION STATUS OF 5 GENES; P16, P15, E-CADHERIN, HIC-1 AND RASSF1A IN THE SAME TISSUES, AND IV) THE RELATIONSHIPS BETWEEN THE ABOVE RESULTS AND THE CLINICOPATHOLOGICAL CHARACTERISTICS, INCLUDING PROGNOSIS. THE DIFFERENCES IN MRNA EXPRESSION LEVELS FOR DNMT1, DNMT3A AND DNMT3B WERE STATISTICALLY SIGNIFICANT BETWEEN HCC AND NORMAL LIVERS (P<0.001), HCC AND CHRONIC HEPATITIS (P<0.001) AND HCC AND CIRRHOSIS (P<0.001). AN INCREASE IN MRNA EXPRESSION LEVELS OF >4-FOLD FOR DNMT3B IN HCCS WAS SIGNIFICANTLY ASSOCIATED WITH A POORER OVERALL SURVIVAL (P=0.027) AND SHORTER METASTASIS-FREE SURVIVAL (P=0.0299). A POORER RECURRENCE-FREE SURVIVAL WAS NOTED IN HCCS WITH A >4-FOLD INCREASE IN DNMT3A MRNA (P=0.0120). THE AVERAGE NUMBERS OF METHYLATED GENES WERE 0, 1.27, 1.38 AND 2.72 FOR NORMAL LIVERS, CHRONIC HEPATITIS, CIRRHOSIS AND HCCS, RESPECTIVELY, AND THIS PROGRESSIVE INCREASE FROM NORMAL LIVERS TO CHRONIC HEPATITIS/CIRRHOSIS THROUGH HCC MAY SUGGEST THAT TUMOR SUPPRESSOR GENE METHYLATION IS AN EARLY EVENT IN HEPATOCARCINOGENESIS. THESE RESULTS FIRST SUGGEST THAT HEPATOCARCINOGENESIS INVOLVES AN INCREASED EXPRESSION OF DNMT1, DNMT3A AND DNMT3B MRNA AND A PROGRESSIVE INCREASE IN THE NUMBER OF METHYLATED GENES FROM NORMAL LIVER, CHRONIC HEPATITIS/CIRRHOSIS TO HCC AND SECONDLY THAT AN INCREASE IN THE DNMT3A AND DNMT3B MRNA LEVELS IN HCCS RELATIVE TO THEIR NON-CANCEROUS TISSUES MAY BE A PREDICTOR OF POOR SURVIVAL.	2007	
                                                                                                                                                                                                                                                     
2 3646  53 INCREASED PROTEIN EXPRESSION OF DNA METHYLTRANSFERASE (DNMT) 1 IS SIGNIFICANTLY CORRELATED WITH THE MALIGNANT POTENTIAL AND POOR PROGNOSIS OF HUMAN HEPATOCELLULAR CARCINOMAS. ALTERATION OF DNA METHYLATION IS ONE OF THE MOST CONSISTENT EPIGENETIC CHANGES IN HUMAN CANCERS. DNA METHYLTRANSFERASE (DNMT) 1 IS A MAJOR ENZYME INVOLVED IN ESTABLISHING GENOMIC METHYLATION PATTERNS. MOST OF THE STUDIES CONCERNING DNMT1 EXPRESSION IN HUMAN CANCERS HAVE BEEN PERFORMED ONLY AT THE MRNA LEVEL. TO DIRECTLY EXAMINE DNMT1 PROTEIN EXPRESSION LEVELS DURING HUMAN HEPATOCARCINOGENESIS, 16 HISTOLOGICALLY NORMAL LIVER TISSUES, 51 NONCANCEROUS LIVER TISSUES EXHIBITING CHRONIC HEPATITIS OR CIRRHOSIS, WHICH ARE CONSIDERED TO BE PRECANCEROUS CONDITIONS, AND 53 HEPATOCELLULAR CARCINOMAS (HCCS) WERE SUBJECTED TO IMMUNOHISTOCHEMIC EXAMINATION. IF MORE THAN 20% OF THE CELLS EXHIBITED NUCLEAR DNMT1 STAINING, THE TISSUE SAMPLE WAS CONSIDERED TO BE DNMT1-POSITIVE. DNMT1 IMMUNOREACTIVITY WAS OBSERVED IN 23 (43%) OF THE HCCS, BUT IN NONE (0%) OF THE HISTOLOGICALLY NORMAL LIVER OR NONCANCEROUS LIVER TISSUES EXHIBITING CHRONIC HEPATITIS OR CIRRHOSIS. THE INCIDENCE OF INCREASED DNMT1 PROTEIN EXPRESSION IN HCCS CORRELATED SIGNIFICANTLY WITH POOR TUMOR DIFFERENTIATION (P = 0.0006) AND PORTAL VEIN INVOLVEMENT (P = 0.0002). MOREOVER, THE RECURRENCE-FREE (P = 0.0001) AND OVERALL (P < 0.0001) SURVIVAL RATES OF PATIENTS WITH HCCS EXHIBITING INCREASED DNMT1 PROTEIN EXPRESSION WERE SIGNIFICANTLY LOWER THAN THOSE OF PATIENTS WITH HCCS THAT DID NOT EXHIBIT INCREASED EXPRESSION. INCREASED DNMT1 PROTEIN EXPRESSION MAY PLAY A CRITICAL ROLE IN THE MALIGNANT PROGRESSION OF HCCS AND BE A BIOLOGIC PREDICTOR OF BOTH HCC RECURRENCE AND A POOR PROGNOSIS IN HCC PATIENTS.	2003	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
3 1342  47 DETECTING ABNORMAL METHYLATION OF TUMOR SUPPRESSOR GENES GSTP1, P16, RIZ1, AND RASSF1A IN HEPATOCELLULAR CARCINOMA AND ITS CLINICAL SIGNIFICANCE. HEPATOCELLULAR CARCINOMA (HCC) HAS A HIGH RATE OF MORTALITY. FURTHER STUDIES INTO EPIGENETIC CHANGES IN HCC, PARTICULARLY THE ABNORMAL METHYLATION OF TUMOR SUPPRESSOR GENES (TSGS), ARE REQUIRED, SINCE THESE CHANGES MAY PROVIDE NOVEL BIOMARKERS FOR EARLY SCREENING AND DIAGNOSIS OF HCC. BY USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MSP), THE PRESENT STUDY DETECTED THE METHYLATION STATUS IN THE PROMOTER REGION OF 4 CANDIDATE TSGS, GSTP1, P16, RIZ1, AND RASSF1A, RESPECTIVELY, IN 35 PAIRED HCC AND TUMOR-ADJACENT LIVER TISSUES IN ADDITION TO 20 NORMAL LIVER TISSUES. THEIR EFFECT ON THE INITIATION AND PROGRESSION OF HCC WAS ALSO INVESTIGATED BY ANALYZING THE CLINICOPATHOLOGICAL DATA. THE RESULTS OF THE PRESENT STUDY REVEALED THAT THE METHYLATION LEVEL OF RIZ1 AND GSTP1 GENES IN HCC WAS SIGNIFICANTLY INCREASED COMPARED WITH THAT IN THE ADJACENT TISSUES (P<0.01) AND THE NORMAL LIVER TISSUES (P<0.01). THE METHYLATION FREQUENCY OF P16 AND RASSF1A GENES WAS NOT SIGNIFICANTLY INCREASED COMPARED WITH THAT OBSERVED IN THE ADJACENT TISSUES (P>0.05) BUT WAS SIGNIFICANTLY INCREASED COMPARED WITH THE NORMAL TISSUES (P<0.01). IN HCC TISSUES, THE METHYLATION FREQUENCY OF THE GSTP1 GENE IN TUMORS WITH CAPSULAR INVASION WAS SIGNIFICANTLY INCREASED COMPARED WITH THAT IN TUMORS WITHOUT CAPSULAR INVASION (P<0.05). THE METHYLATION FREQUENCY OF P16 GENE IN HEPATITIS B SURFACE ANTIGEN (HBSAG)-POSITIVE HCC PATIENTS WAS SIGNIFICANTLY INCREASED COMPARED WITH THAT IN HBSAG-NEGATIVE PATIENTS (P<0.05). THE METHYLATION STATUS OF RIZ1 AND RASSF1A GENES WAS NOT SIGNIFICANTLY CORRELATED WITH THE CLINICOPATHOLOGICAL DATA (P>0.05). PREVIOUS STUDIES HAVE DEMONSTRATED THAT THE METHYLATION STATUS OF RIZ1 AND GSTP1 GENES IS HCC-SPECIFIC, AND THUS MAY BE USED AS A BIOMARKER TO ASSIST THE CLINICAL DIAGNOSIS OF HCC. WHILE THE METHYLATION OF GSTP1 GENE PROMOTER MAY ASSOCIATE WITH THE INVASIVENESS OF HCC, CHRONIC HEPATITIS B VIRUS INFECTION MAY BE THE CAUSE OF METHYLATION-INDUCED P16 INACTIVATION.	2015	
                                                                                                                                                                                                   
4 6692  48 VARIABLE DNA METHYLATION PATTERNS ASSOCIATED WITH PROGRESSION OF DISEASE IN HEPATOCELLULAR CARCINOMAS. HEPATOCELLULAR CARCINOMA (HCC) MOST COMMONLY ARISES FROM CHRONIC INFLAMMATION DUE TO VIRAL INFECTION, AS A RESULT OF GENETIC AND EPIGENETIC ABNORMALITIES. A GLOBAL PICTURE OF EPIGENETIC CHANGES IN HCC IS LACKING. WE USED METHYLATED CPG ISLAND AMPLIFICATION MICROARRAYS (MCAMS) TO STUDY 6458 CPG ISLANDS IN HCC AND ADJACENT PRENEOPLASTIC TISSUES [CHRONIC HEPATITIS (CH) OR LIVER CIRRHOSIS (LC)] IN COMPARISON WITH NORMAL LIVER TISSUES WHERE NEITHER VIRAL INFECTION NOR HEPATITIS HAS EXISTED. MCAM IDENTIFIED 719 (11%) PROMINENT GENES OF HYPERMETHYLATION IN HCCS. HCCS ARISING FROM LC HAD SIGNIFICANTLY MORE METHYLATION THAN THOSE ARISING FROM CH (1249 GENES OR 19% VERSUS 444 GENES OR 7%, P < 0.05). THERE WERE FOUR PATTERNS OF ABERRANT METHYLATION: TYPE I (4%, E.G. MATRIX METALLOPROTEINASE 14) SHOWS A SUBSTANTIALLY HIGH METHYLATION LEVEL IN ADJACENT TISSUE AND DOES NOT INCREASE FURTHER IN CANCER. TYPE II (55%, E.G. RASSF1A) SHOWS PROGRESSIVELY INCREASING METHYLATION FROM ADJACENT TISSUE TO HCC. TYPE III (4%, E.G. GNA14) SHOWS DECREASED METHYLATION IN ADJACENT TISSUE BUT EITHER SIMILAR OR INCREASED METHYLATION IN HCC. TYPE IV (37%, E.G. CDKN2A) SHOWS LOW LEVELS OF METHYLATION IN NORMAL TISSUE AND ADJACENT TISSUE BUT HIGH LEVELS IN HCC. THESE DNA METHYLATION CHANGES WERE CONFIRMED BY QUANTITATIVE PYROSEQUENCING METHYLATION ANALYSIS IN REPRESENTATIVE 24 GENES AND WERE ANALYZED FOR CORRELATION WITH CLINICOPATHOLOGICAL PARAMETERS IN 38 PATIENTS. INTRIGUINGLY, METHYLATION IN THE TYPE IV GENES IS CHARACTERISTIC OF MODERATELY/POORLY DIFFERENTIATED CANCER. OUR GLOBAL EPIGENOME ANALYSIS REVEALS DISTINCT PATTERNS OF METHYLATION THAT ARE PROBABLY TO REPRESENT DIFFERENT PATHOPHYSIOLOGIC PROCESSES IN HCCS.	2008	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
5 3897  48 LARGE-SCALE ANALYSIS OF THE GENETIC AND EPIGENETIC ALTERATIONS IN HEPATOCELLULAR CARCINOMA FROM SOUTHEAST CHINA. OUR KNOWLEDGE ABOUT MOLECULAR ALTERATIONS DURING HEPATOCARCINOGENESIS IS STILL FRAGMENTARY, DUE TO LACK OF COMPREHENSIVE GENETIC AND EPIGENETIC ANALYSES IN THE SAME SET OF HEPATOCELLULAR CARCINOMAS (HCCS). IN THIS STUDY, WE CONDUCTED A LARGE-SCALE ANALYSIS, INCLUDING MUTATION SCREENING IN 50 GENES AND METHYLATION ASSAYS IN THREE GENES IN 54 PAIRS OF HCCS AND THEIR NEIGHBORING NON-CANCEROUS TISSUES. ALL SAMPLES WERE COLLECTED FROM THE RESIDENTS IN SOUTHEAST CHINA. WE FOUND HBV INFECTION AND CHRONIC HEPATITIS/CIRRHOSIS IN 83.3% AND 98.1% OF THE CASES, RESPECTIVELY. MUTATIONS WERE IDENTIFIED IN 18 OUT OF 54 (33.3%) SAMPLES, WITH P53 ALTERATIONS IN 14 CASES AND BETA-CATENIN MUTATIONS IN FOUR TUMORS. NO MUTATIONS WERE IDENTIFIED IN THE NEIGHBORING TISSUES. INTERESTINGLY, 9 OUT OF 14 (64.3%) TUMORS CARRYING P53 MUTATIONS DISPLAYED SUBSTITUTION OF SERINE BY ARGININE AT CODON 249, A CHARACTERISTIC CHANGE BELIEVED TO BE INDUCED BY AFLATOXIN-B1. FURTHERMORE, P53 MUTATION WAS SIGNIFICANTLY ASSOCIATED WITH SHORTER RECURRENCE-FREE SURVIVAL (P=0.004). THE RESULTS ALSO REVEALED ABERRANT METHYLATION IN TWO OR MORE GENES IN AS HIGH AS 90% OF TUMORS AND 40% OF ADJACENT TISSUES. THE FREQUENCY OF RASSF1A HYPERMETHYLATION WAS MUCH HIGHER THAN THAT OF P16INK4A AND HAI2 IN BOTH HCC AND NEIGHBORING TISSUES, INDICATING THAT DEREGULATION OF RASSF1A MAY PRECEDE THE OTHER TWO GENES. THESE DATA SUGGEST THAT ABERRANT METHYLATION OCCURS BEFORE MUTATION AND IS AN EARLY EVENT IN THE DEVELOPMENT OF THIS SET OF HCC. OUR FINDINGS HIGHLIGHT P53 AS A PROGNOSTIC FACTOR OF HCC AND RASSF1A AS A POTENTIAL TARGET IN PREVENTING MALIGNANT TRANSFORMATION OF HEPATOCYTES.	2008	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
6  153  44 ABERRANT METHYLATION OF MULTIPLE TUMOR SUPPRESSOR GENES IN AGING LIVER, CHRONIC HEPATITIS, AND HEPATOCELLULAR CARCINOMA. ABERRANT DNA METHYLATION IS AN IMPORTANT EPIGENETIC ALTERATION IN HEPATOCELLULAR CARCINOMA (HCC). HOWEVER, THE MOLECULAR PROCESSES UNDERLYING THE METHYLATOR PHENOTYPE AND THE CONTRIBUTION OF HEPATITIS VIRUSES ARE POORLY UNDERSTOOD. THE CURRENT STUDY IS A COMPREHENSIVE METHYLATION ANALYSIS OF HUMAN LIVER TISSUE SPECIMENS. A TOTAL OF 176 LIVER TISSUES, INCLUDING 77 PAIRS OF HCCS AND MATCHING NONCANCEROUS LIVER AND 22 NORMAL LIVERS, WERE ANALYZED FOR METHYLATION. METHYLATION OF 19 EPIGENETIC MARKERS WAS QUANTIFIED, AND THE RESULTS WERE CORRELATED WITH DIFFERENT DISEASE STATES AND THE PRESENCE OR ABSENCE OF HEPATITIS B VIRUS (HBV) AND HEPATITIS C VIRUS (HCV) INFECTIONS. BASED ON METHYLATION PROFILES, THE 19 LOCI WERE CATEGORIZED INTO 3 GROUPS. NORMAL LIVER TISSUES SHOWED METHYLATION PRIMARILY IN GROUP 1 LOCI (HIC-1, CASP8, GSTP1, SOCS1, RASSF1A, P16, APC), WHICH WAS SIGNIFICANTLY HIGHER THAN GROUP 2 (CDH1, RUNX3, RIZ1, SFRP2, MINT31) AND GROUP 3 MARKERS (COX2, MINT1, CACNA1G, RASSF2, MINT2, REPRIMO, DCC) (P < 0.0001). NONCANCEROUS LIVERS DEMONSTRATED INCREASED METHYLATION IN BOTH GROUP 1 AND GROUP 2 LOCI. METHYLATION WAS SIGNIFICANTLY MORE ABUNDANT IN HCV-POSITIVE LIVERS COMPARED WITH NORMAL LIVER TISSUES. CONVERSELY, HCC SHOWED FREQUENT METHYLATION AT EACH LOCUS INVESTIGATED IN ALL 3 GROUPS. HOWEVER, THE GROUP 3 LOCI SHOWED MORE DENSE AND FREQUENT METHYLATION IN HCV-POSITIVE CANCERS COMPARED WITH BOTH HBV-POSITIVE CANCERS AND VIRUS-NEGATIVE CANCERS (P < 0.0001). CONCLUSION: METHYLATION IN HCC IS FREQUENT BUT OCCURS IN A GENE-SPECIFIC AND DISEASE-SPECIFIC MANNER. METHYLATION PROFILING ALLOWED US TO DETERMINE THAT ABERRANT METHYLATION IS COMMONLY PRESENT IN NORMAL AGING LIVERS, AND SEQUENTIALLY PROGRESSES WITH ADVANCING STAGES OF CHRONIC VIRAL INFECTION. FINALLY, OUR DATA PROVIDE EVIDENCE THAT HCV INFECTION MAY ACCELERATE THE METHYLATION PROCESS AND SUGGESTS A CONTINUUM OF INCREASING METHYLATION WITH PERSISTENT VIRAL INFECTION AND CARCINOGENESIS IN THE LIVER.	2008	
                                                                                                                                                                                                                                 
7 4905  51 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	
                                                                                                                                                                                                                                                                                                                                                                                                    
8 5844  42 STUDY OF PROMOTER HYPOMETHYLATION PROFILES OF RAS ONCOGENES IN HEPATOCELLULAR CARCINOMA DERIVED FROM HEPATITIS C VIRUS GENOTYPE 3A IN PAKISTANI POPULATION. EPIGENETIC MODIFICATIONS SUCH AS DNA METHYLATION CONTRIBUTE TO PROGRESSION OF HEPATITIS C VIRUS (HCV) INFECTION TO LIFE-THREATENING HEPATOCELLULAR CARCINOMA (HCC) BY PROMOTING THE SILENCING OF TUMOR SUPPRESSOR GENES THROUGH DNA HYPERMETHYLATION AND BY CAUSING GENOMIC INSTABILITY THROUGH GLOBAL HYPOMETHYLATION. HOWEVER FEW STUDIES HAVE ADDRESSED THE PROMOTER REGION HYPOMETHYLATION STATUS OF THE ONCOGENES INVOLVED IN HCV DERIVED HCC. IN THIS STUDY, WE ANALYZED THE PROMOTER REGION METHYLATION PATTERN OF RAS ONCOGENES (HRAS, KRAS, AND NRAS) USING METHYLATION-SPECIFIC PCR FOR 50 CHRONIC HCV PATIENTS INFECTED WITH GENOTYPE 3A (27 HCC PATIENTS AND 23 CONTROL NON-HCC PATIENTS). METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION ANALYSIS REVEALED THAT THE NRAS ONCOGENE PROMOTER (P = .0025) WAS SIGNIFICANTLY HYPOMETHYLATED IN HCC PATIENTS COMPARED TO THE NON-HCC PATIENTS SUGGESTING ITS CONTRIBUTION TO THE PROGRESSION OF HCV TOWARDS HCC. TO IDENTIFY THE AGENT FOR ALTERATION IN THE RAS ONCOGENE EXPRESSION, 7 HCV GENES WERE EXPRESSED IN THE HUH-7 CELL LINE FOLLOWED BY MEASUREMENT OF THE NRAS EXPRESSION LEVEL IN HUH-7 BY A QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION. AN INCREASE IN THE MESSENGER RNA LEVEL OF THE NRAS GENE WAS DETECTED WHEN HUH-7 WERE TRANSFECTED WITH CORE, NS5A, AND NS2 GENES. OUR FINDINGS SUGGEST THE INVOLVEMENT OF NRAS ONCOGENE IN THE PATHOGENESIS OF HCV3A DERIVED HCC IN PAKISTANI POPULATION AND ALSO IDENTIFIES THE HCV GENES RESPONSIBLE FOR ITS ENHANCED EXPRESSION. OUR STUDY RAISES THE HYPOTHESIS THAT A SINGLE HCV GENE MAY INCREASE THE CHANCES OF MALIGNANCY. THEREFORE, OUR STUDY MAY HAVE IDENTIFIED A USEFUL EPIGENETIC BIOMARKER OF HCC PROGRESSION IN HCV PATIENTS AND MAY HELP TO DEVELOP NOVEL DIAGNOSTIC TOOLS.	2018	
                                                                                                                                                                                                                                                                                                                                                                                                                                                  
9 4903  37 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	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
10 2847  28 FREQUENT P15 PROMOTER METHYLATION IN TUMOR AND PERIPHERAL BLOOD FROM HEPATOCELLULAR CARCINOMA PATIENTS. WE PROSPECTIVELY ANALYZED P15 METHYLATION PATTERNS IN 25 SURGICALLY RESECTED TUMORS AND 130 PLASMA, SERUM, AND BUFFY COAT SAMPLES FROM HEPATOCELLULAR CARCINOMA (HCC) PATIENTS, CONTROLS WITH CHRONIC HEPATITIS/CIRRHOSIS, AND HEALTHY SUBJECTS. USING METHYLATION-SPECIFIC PCR, WE DEMONSTRATED FOR THE FIRST TIME P15 PROMOTER METHYLATION IN 64% OF TUMORS AND 25% (4 OF 16) OF PATIENTS' PLASMA AND SERUM SAMPLES. CONCURRENT P15 AND P16 METHYLATION WAS SHOWN IN 48% OF TUMORS, AND P15/P16 METHYLATION WAS DETECTED IN THE PLASMA/SERUM OF 92% (11 OF 12) OF PATIENTS. OF NOTE, 75% OF 12 PATIENTS WITH CONCURRENT TUMOR METHYLATION DEVELOPED CLINICAL METASTASIS/RECURRENCE (P = 0.027). IN BUFFY COAT SAMPLES, P15 METHYLATION WAS DETECTED IN ALL EIGHT PATIENTS WITH TUMOR P15 METHYLATION, SUGGESTING THE PRESENCE OF CIRCULATING TUMOR CELLS. NONE OF THE CONTROL SAMPLES WERE METHYLATION POSITIVE. OUR DATA UNDERSCORE THE IMPORTANT ROLE(S) OF P15 AND P16 METHYLATION IN HEPATOCARCINOGENESIS AND TUMOR PROGRESSION. AMONG 92% (23 OF 25) OF PATIENTS WITH TUMOR P15/P16 METHYLATION, CIRCULATING TUMOR DNA AND HCC CELLS WERE DETECTED IN THE PERIPHERAL BLOOD OF 87% (20 OF 23) OF PATIENTS. THE COMBINATION OF THESE EPIGENETIC MARKERS MAY PROVE VALUABLE FOR NONINVASIVE HCC DIAGNOSIS AND DISEASE MONITORING.	2000	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
11 2682  42 EVALUATION OF SERUM LINE-1 HYPOMETHYLATION AS A PROGNOSTIC MARKER FOR HEPATOCELLULAR CARCINOMA. BACKGROUND AND STUDY AIMS: GLOBAL HYPOMETHYLATION IS ONE OF THE MOST CONSISTENT EPIGENETIC CHANGES IN CANCER. DEVELOPMENT OF HEPATOCELLULAR CARCINOMA (HCC) MUST BE UNDERSTOOD AS A MULTISTEP PROCESS WITH ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS. IN THE LAST DECADES, IN ADDITION TO GENETIC ALTERATIONS, EPIGENETIC CHANGES HAVE BEEN RECOGNIZED AS AN IMPORTANT AND ALTERNATIVE MECHANISM IN TUMOURIGENESIS. WE INVESTIGATED THE CLINICAL IMPLICATIONS OF GLOBAL HYPOMETHYLATION IN THE SERA OF PATIENTS WITH HEPATOCELLULAR CARCINOMA (HCC). PATIENTS AND METHODS: PCR WAS USED TO ASSESS THE METHYLATION STATUS OF LONG INTERSPERSED NUCLEAR ELEMENT TYPE 1 (LINE-1) REPETITIVE SEQUENCES IN GENOMIC DNA DERIVED FROM SERA OF 50 PATIENTS WITH HCC, 20 PATIENTS WITH CIRRHOSIS, 20 PATIENTS WITH CHRONIC HEPATITIS C AND 10 HEALTHY SUBJECTS. RESULTS: SERUM GENOME HYPOMETHYLATION WAS SIGNIFICANTLY INCREASED IN PATIENTS WITH HCC (P<0.001). THE LEVELS OF SERUM LINE-1 HYPOMETHYLATION AT INITIAL PRESENTATION CORRELATED SIGNIFICANTLY WITH TUMOUR SIZE, TUMOUR NUMBER AND ALPHA-FOETOPROTEIN LEVEL. MOREOVER HIGH SERUM LINE-1 HYPOMETHYLATION CORRELATES SIGNIFICANTLY WITH POOR SURVIVAL. CONCLUSION: SERUM LINE-1 HYPOMETHYLATION MAY SERVE AS A PROGNOSTIC MARKER FOR PATIENTS WITH HCC.	2011	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
12 2234  43 EPIGENETIC MODIFICATIONS PRECEDE MOLECULAR ALTERATIONS AND DRIVE HUMAN HEPATOCARCINOGENESIS. DEVELOPMENT OF PRIMARY LIVER CANCER IS A MULTISTAGE PROCESS. DETAILED UNDERSTANDING OF SEQUENTIAL EPIGENETIC ALTERATIONS IS LARGELY MISSING. HERE, WE PERFORMED INFINIUM HUMAN METHYLATION 450K BEADCHIPS AND RNA-SEQ ANALYSES FOR GENOME-WIDE METHYLOME AND TRANSCRIPTOME PROFILING OF CIRRHOTIC LIVER (N = 7), LOW- (N = 4) AND HIGH-GRADE (N = 9) DYSPLASTIC LESIONS, AND EARLY (N = 5) AND PROGRESSED (N = 3) HEPATOCELLULAR CARCINOMAS (HCC) SYNCHRONOUSLY DETECTED IN 8 PATIENTS WITH HCC WITH CHRONIC HEPATITIS B INFECTION. INTEGRATIVE ANALYSES OF EPIGENETICALLY DRIVEN MOLECULAR CHANGES WERE IDENTIFIED AND VALIDATED IN 2 INDEPENDENT COHORTS COMPRISING 887 HCCS. MITOCHONDRIAL DNA SEQUENCING WAS FURTHER EMPLOYED FOR CLONALITY ANALYSES, INDICATING MULTICLONAL ORIGIN IN THE MAJORITY OF INVESTIGATED HCCS. ALTERATIONS IN DNA METHYLATION PROGRESSIVELY INCREASED FROM LIVER CIRRHOSIS (CL) TO DYSPLASTIC LESIONS AND REACHED A MAXIMUM IN EARLY HCCS. ASSOCIATED EARLY ALTERATIONS IDENTIFIED BY INGENUITY PATHWAY ANALYSIS (IPA) INVOLVED APOPTOSIS, IMMUNE REGULATION, AND STEMNESS PATHWAYS, WHILE LATE CHANGES CENTERED ON CELL SURVIVAL, PROLIFERATION, AND INVASION. WE FURTHER VALIDATED 23 PUTATIVE EPIDRIVERS WITH CONCOMITANT EXPRESSION CHANGES AND ASSOCIATED WITH OVERALL SURVIVAL. FUNCTIONALLY, STRIATIN 4 (STRN4) WAS DEMONSTRATED TO BE EPIGENETICALLY REGULATED, AND INHIBITION OF STRN4 SIGNIFICANTLY SUPPRESSED TUMORIGENICITY OF HCC CELL LINES. OVERALL, APPLICATION OF INTEGRATIVE GENOMIC ANALYSES DEFINES EPIGENETIC DRIVER ALTERATIONS AND PROVIDES PROMISING TARGETS FOR POTENTIALLY NOVEL THERAPEUTIC APPROACHES.	2021	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
13 5357  45 REACTIVE OXYGEN SPECIES INDUCE EPIGENETIC INSTABILITY THROUGH THE FORMATION OF 8-HYDROXYDEOXYGUANOSINE IN HUMAN HEPATOCARCINOGENESIS. CHRONIC HEPATITIS C (CHC) TRIGGERS OXIDATIVE STRESS AND CONTRIBUTES TO THE EMERGENCE OF HEPATOCELLULAR CARCINOMA (HCC). WE PREVIOUSLY REPORTED THAT TUMOR SUPPRESSOR GENE (TSG) METHYLATION IS A CRITICAL FACTOR DURING THE EARLY STAGES OF HEPATOCARCINOGENESIS. IN THIS STUDY, WE CLARIFY THE ASSOCIATION BETWEEN OXIDATIVE STRESS AND EPIGENETIC ALTERATIONS DURING HEPATOCARCINOGENESIS. WE EXAMINED DNA OXIDATION AND METHYLATION PROFILES IN 128 LIVER BIOPSY SAMPLES FROM CHC PATIENTS. THE DNA OXIDATION AND METHYLATED TSG NUMBERS WERE QUANTIFIED USING IMMUNOHISTOCHEMICAL ANALYSIS OF 8-HYDROXYDEOXYGUANOSINE (8-OHDG) AND QUANTITATIVE PCR FOR 11 TSGS, RESPECTIVELY. THE QUANTITATIVE CHROMATIN IMMUNOPRECIPITATION-PCR (CHIP-QPCR) ASSAY IN HEPG2 AND FETAL LIVER HC CELLS TREATED WITH H2O2 WAS USED TO QUANTIFY TRIMETHYL-H3K4, ACETYLATED-H4K16 (AN ACTIVE CHROMATIN MARKER), TRIMETHYL-H3K27 (A REPRESSIVE CHROMATIN MARKER) AND 8-OHDG. WE ANALYZED 30 PROMOTERS OF 25 DIFFERENT TSGS BY QPCR. THE HIGH LEVELS OF 8-OHDG WAS THE ONLY VARIABLE THAT WAS SIGNIFICANTLY ASSOCIATED WITH THE INCREASED NUMBER OF METHYLATED TSGS IN CHC (P < 0.0001). THE CHIP-QPCR REVEALED THAT AFTER H2O2 TREATMENT OF THE CELL LINES, THE 8-OHDG-BOUND PROMOTERS SHOWED A MODIFICATION FROM AN ACTIVE CHROMATIN (TRIMETHYL-H3K4 AND ACETYLATED-H4K16 DOMINANT) TO A REPRESSIVE CHROMATIN (TRIMETHYL-H3K27 DOMINANT) STATUS. WE CONCLUDE THAT OXIDATIVE STRESS ALTERS THE CHROMATIN STATUS, WHICH LEADS TO ABNORMAL METHYLATION OF TSGS, AND CONTRIBUTES TO HEPATOCARCINOGENESIS IN CHC PATIENTS.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
14  507  46 ASSOCIATION OF INCREASED DNA METHYLTRANSFERASE EXPRESSION WITH CARCINOGENESIS AND POOR PROGNOSIS IN PANCREATIC DUCTAL ADENOCARCINOMA. INTRODUCTION: EPIGENETIC MODIFICATIONS PLAY AN IMPORTANT ROLE IN MULTISTAGE CARCINOGENESIS. THE ROLE OF THE THREE FUNCTIONAL DNA METHYLTRANSFERASES (DNMTS) IN PANCREATIC CARCINOGENESIS HAS NOT BEEN FULLY UNDERSTOOD. THE MAIN GOAL OF THIS STUDY WAS TO EXAMINE DNMT EXPRESSION IN DIFFERENT STAGES OF PANCREATIC DUCTAL ADENOCARCINOMA (PDAC), AND EVALUATE THEIR PROGNOSTIC SIGNIFICANCE IN PDAC. MATERIALS AND METHODS: A LARGE NUMBER OF PREMALIGNANT AND MALIGNANT PANCREATIC LESIONS WERE OBTAINED BY MANUAL MICRODISSECTION. QUANTITATIVE REAL-TIME RT-PCR WAS USED TO DETECT DNMTS MRNA EXPRESSION. NONPARAMETRIC TEST, LOGRANK TEST AND COX REGRESSION ANALYSIS WERE USED TO EVALUATE THE CLINICAL SIGNIFICANCE OF DNMT EXPRESSION. RESULTS: THE MRNA EXPRESSION OF THE THREE DNMTS INCREASED WITH THE DEVELOPMENT OF PANCREATIC CANCER FROM NORMAL DUCT TO PANCREATIC INTRADUCTAL NEOPLASIA AND FURTHER TO PDAC, AND WERE STATISTICALLY CORRELATED WITH EACH OTHER. EXPRESSION OF THE THREE DNMTS WAS STATISTICALLY CORRELATED WITH TNM STAGING AND HISTORY OF CHRONIC PANCREATITIS. DNMT3A AND DNMT3B, BUT NOT DNMT1 EXPRESSION, WAS STATISTICALLY CORRELATED WITH TUMOUR SIZE. PATIENTS WITH HIGHER LEVELS OF DNMT1, DNMT3A AND/OR DNMT3B EXPRESSION HAD AN OVERALL LOWER SURVIVAL THAN THOSE WITH LOWER LEVELS OF EXPRESSION. UNIVARIATE ANALYSIS SHOWED THAT HIGH EXPRESSION LEVELS OF DNMTS, ALCOHOL CONSUMPTION, TUMOUR DIFFERENTIATION AND TNM STAGING WERE STATISTICALLY SIGNIFICANT RISK FACTORS. MULTIVARIATE ANALYSIS SHOWED THAT HIGH LEVEL OF DNMT3B EXPRESSION AND TUMOUR DIFFERENTIATION WERE STATISTICALLY SIGNIFICANT INDEPENDENT POOR PROGNOSTIC FACTORS. CONCLUSIONS: THESE RESULTS SUGGESTED THAT PANCREATIC CARCINOGENESIS INVOLVES AN INCREASED MRNA EXPRESSION OF THREE DNMTS, AND THEY MAY BECOME VALUABLE DIAGNOSTIC AND PROGNOSTIC MARKERS AS WELL AS POTENTIAL THERAPEUTIC TARGETS FOR PANCREATIC CANCER.	2012	
                                                                                                                                                                                                                                                                                                                                      
15 3264  39 HEPATITIS VIRUS INFECTION AFFECTS DNA METHYLATION IN MICE WITH HUMANIZED LIVERS. BACKGROUND & AIMS: CELLS OF TUMORS ASSOCIATED WITH CHRONIC INFLAMMATION FREQUENTLY HAVE ALTERED PATTERNS OF DNA METHYLATION, INCLUDING HEPATOCELLULAR CARCINOMAS. CHRONIC HEPATITIS HAS ALSO BEEN ASSOCIATED WITH ABERRANT DNA METHYLATION, BUT LITTLE IS KNOWN ABOUT THEIR RELATIONSHIP. METHODS: PYROSEQUENCING WAS USED TO DETERMINE THE METHYLATION STATUS OF CULTURED HUH7.5.1 HEPATOMA CELLS AFTER HEPATITIS C VIRUS (HCV) INFECTION. WE ALSO STUDIED MICE WITH SEVERE COMBINED IMMUNODEFICIENCY CARRYING THE UROKINASE-TYPE PLASMINOGEN ACTIVATOR TRANSGENE CONTROLLED BY AN ALBUMIN PROMOTER (UROKINASE-TYPE PLASMINOGEN ACTIVATOR/SEVERE COMBINED IMMUNODEFICIENT MICE), IN WHICH UP TO 85% OF HEPATOCYTES WERE REPLACED BY HUMAN HEPATOCYTES (CHIMERIC MICE). MICE WERE GIVEN INTRAVENOUS INJECTIONS OF HEPATITIS B VIRUS (HBV) OR HCV, LIVER TISSUES WERE COLLECTED, AND DNA METHYLATION PROFILES WERE DETERMINED AT DIFFERENT TIME POINTS AFTER INFECTION. WE ALSO COMPARED METHYLATION PATTERNS BETWEEN PAIRED SAMPLES OF HEPATOCELLULAR CARCINOMAS AND ADJACENT NONTUMOR LIVER TISSUES FROM PATIENTS. RESULTS: NO REPRODUCIBLE CHANGES IN DNA METHYLATION WERE OBSERVED AFTER INFECTION OF HUH7.5.1 CELLS WITH HCV. LIVERS FROM HBV- AND HCV-INFECTED MICE HAD GENOME-WIDE, TIME-DEPENDENT CHANGES IN DNA METHYLATION, COMPARED WITH UNINFECTED UROKINASE-TYPE PLASMINOGEN ACTIVATOR/SEVERE COMBINED IMMUNODEFICIENT MICE. THERE WERE CHANGES IN 160 +/- 63 GENES IN HBV-INFECTED AND 237 +/- 110 GENES IN HCV-INFECTED MICE. METHYLATION OF 149 COMMON GENES INCREASED IN HBV- AND HCV-INFECTED MICE; METHYLATION OF SOME OF THESE GENES ALSO INCREASED IN HEPATOCELLULAR CARCINOMA SAMPLES FROM PATIENTS COMPARED WITH NONTUMOR TISSUES. EXPRESSION OF IFNG, WHICH IS EXPRESSED BY NATURAL KILLER CELLS, INCREASED SIGNIFICANTLY IN CHIMERIC LIVERS, IN CONCORDANCE WITH INDUCTION OF DNA METHYLATION, AFTER INFECTION WITH HBV OR HCV. INDUCTION OF IFNG WAS REDUCED AFTER ADMINISTRATION OF AN INHIBITOR OF NATURAL KILLER CELL FUNCTION (ANTI-ASIALO GM1). CONCLUSIONS: IN CHIMERIC MICE WITH HUMANIZED LIVERS, INFECTION WITH HBV AND HCV APPEARS TO ACTIVATE A NATURAL KILL CELL-DEPENDENT INNATE IMMUNE RESPONSE. THIS CONTRIBUTES TO THE INDUCTION AND ACCUMULATION OF ABERRANT DNA METHYLATION IN HUMAN HEPATOCYTES.	2014	

16 1615  34 DNA METHYLTRANSFERASE 3B PLAYS A PROTECTIVE ROLE AGAINST HEPATOCARCINOGENESIS CAUSED BY CHRONIC INFLAMMATION VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS. MOST HEPATOCELLULAR CARCINOMAS (HCCS) DEVELOP ON THE BASIS OF CHRONIC HEPATITIS, BUT THE MECHANISM OF EPIGENETIC REGULATION IN INFLAMMATORY HEPATOCARCINOGENESIS HAS YET TO BE ELUCIDATED. AMONG DE NOVO DNA METHYLTRANSFERASES (DNMTS), DNMT3B HAS LATELY BEEN REPORTED TO ACT SPECIFICALLY ON ACTIVELY TRANSCRIBED GENES, SUGGESTING THE POSSIBILITY THAT IT PLAYS A ROLE IN THE PATHOGENESIS OF CANCER. WE CONFIRMED THAT DNMT3B ISOFORMS LACKING ITS CATALYTIC DOMAIN WERE HIGHLY EXPRESSED IN HCCS COMPARED WITH NON-TUMOROUS LIVER TISSUE. TO ELUCIDATE THE ROLE OF DNMT3B IN HEPATOCARCINOGENESIS, WE GENERATED A GENETICALLY ENGINEERED MOUSE MODEL WITH HEPATOCYTE-SPECIFIC DNMT3B DELETION. THE LIVER OF THE DNMT3B-DEFICIENT MICE EXHIBITED AN EXACERBATION OF THIOACETAMIDE-INDUCED HEPATITIS, PROGRESSION OF LIVER FIBROSIS AND A HIGHER INCIDENCE OF HCC COMPARED WITH THE LIVER OF THE CONTROL MICE. WHOLE-GENOME BISULFITE SEQUENCING VERIFIED A LOWER CG METHYLATION LEVEL IN THE DNMT3B-DEFICIENT LIVER, DEMONSTRATING DIFFERENTIALLY METHYLATED REGIONS THROUGHOUT THE GENOME. TRANSCRIPTOME ANALYSIS REVEALED DECREASED EXPRESSION OF GENES RELATED TO OXIDATIVE PHOSPHORYLATION IN THE DNMT3B-DEFICIENT LIVER. MOREOVER, PRIMARY HEPATOCYTES ISOLATED FROM THE DNMT3B-DEFICIENT MICE SHOWED REDUCED MITOCHONDRIAL RESPIRATORY CAPACITY, LEADING TO THE ENHANCEMENT OF OXIDATIVE STRESS IN THE LIVER TISSUE. OUR FINDINGS SUGGEST THE PROTECTIVE ROLE OF DNMT3B AGAINST CHRONIC INFLAMMATION AND HCC DEVELOPMENT VIA MAINTAINING MITOCHONDRIAL HOMEOSTASIS.	2020	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
17 3248  34 HEPATITIS B VIRUS GENOME ASYMMETRY IN HEPATOCELLULAR CARCINOMA. BACKGROUND: THE ASSOCIATION BETWEEN HEPATITIS B VIRUS (HBV) MUTATIONS AND HEPATOCARCINOGENESIS WERE REPORTED IN THE LITERATURE. PREFERENCE FOR G OVER C IN THE LEADING DNA STRAND HAS BEEN REPORTED TO ACCOUNT FOR THE ASYMMETRY IN NUCLEOTIDE (NT) COMPOSITION. THE AIM OF THIS STUDY WAS TO ANALYZE THE COMPLETE GENOME SEQUENCE AND COMPOSITIONAL ASYMMETRY OF HBV IN DIFFERENT STAGES OF HEPATITIS B. METHODS: FULL GENOME SEQUENCING OF 24 PATIENTS WITH CHRONIC HEPATITIS B, SOME OF WHOM ALSO HAD CIRRHOSIS AND HEPATOCELLULAR CARCINOMA (HCC) WAS PERFORMED. MUTATIONS ANALYSIS WAS IMPLEMENTED IN A COMPARISON WITH A HBV GENOTYPE D REFERENCE FROM AN INTERNATIONAL DNA DATABASE. CPGPROD, A WEB-BASED APPLICATION, WAS USED TO EVALUATE CG CONTENT AND PREDICT CPG ISLANDS. RESULTS: ALL STRAINS WERE 3182 BASE PAIRS (BP) IN LENGTH, EXCEPT FOR TWO CASES OF HCC IN WHICH 9 AND 21 NT, RESPECTIVELY, WERE DELETED IN PRES2. THE GENETIC RELATEDNESS OF THESE ISOLATES WAS 97%-100%. THERE WERE COMMON CPG-RICH REGIONS IN ALL 24 ISOLATED FULL GENOME SEQUENCES, HOWEVER A STRONG NEGATIVE GC SKEW FOR FORMING A CPG ISLAND IN THE MINUS STRAND WERE EXHIBITED IN OVERLAP WITH ENHANCER I IN THREE HCC PATIENTS, A CIRRHOTIC PATIENT AND THREE WITH CHRONIC HEPATITIS. CONCLUSION: THE HIGH PERCENTAGE OF SEQUENCE IDENTITY BETWEEN HBV ISOLATES IN OUR PATIENTS DEMONSTRATES THAT GENOMIC FACTORS, EXCEPT FOR GENOTYPE, ARE INVOLVED IN HEPATOCARCINOGENESIS. VARIATIONS IN GC CONTENT WHICH WERE CAUSED BY A DIFFERENT SPECTRUM OF MUTATIONS MAY AFFECT DNA COMPOSITIONAL ASYMMETRY AND EPIGENETIC MODIFICATION OF HBV DNA IN HCC.	2012	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
18 6770  51 [ABERRANT METHYLATION OF MULTIPLE GENES AND ITS CLINICAL IMPLICATION IN HEPATOCELLULAR CARCINOMA]. OBJECTIVE: TO INVESTIGATE THE METHYLATION FREQUENCIES OF MULTIPLE TUMOR SUPPRESSOR GENES (TSGS) IN HEPATOCELLULAR CARCINOMA (HCC) AND THE CLINICAL IMPLICATION OF ABERRANT DNA METHYLATION IN MOLECULAR CARCINOGENESIS OF HCC. METHODS: SIXTY SAMPLES OF HCC AND THE PAIRED ADJACENT LIVER TISSUE, 16 SAMPLES FROM POST-HEPATITIS CIRRHOTIC LIVERS, 5 FROM LIVERS WITH CHRONIC HEPATITIS AND 5 FROM NORMAL LIVERS WERE COLLECTED. EIGHT TSGS FREQUENTLY SILENCED BY HYPERMETHYLATION OF THEIR PROMOTERS IN VARIOUS TYPES OF DIGESTIVE TUMORS WERE SELECTED, INCLUDING APC, RASSF1A, P16, GSTP1, MGMT, DAPK, SOCS-1 AND RIZ1. THE STATUS OF PROMOTER METHYLATION IN THESE 8 GENES WAS INVESTIGATED USING METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. THE CLINICOPATHOLOGICAL DATA OF HCC WERE ALSO ANALYZED IN ORDER TO EVALUATE THE CLINICAL IMPLICATION OF ABERRANT METHYLATION IN HCC. RESULTS: METHYLATION OF THE 8 TSGS WAS QUITE FREQUENT IN HCC, WITH A METHYLATION RATE OF 95.0% IN RASSF1A, 90.0% IN APC, 73.3% IN GSTP1, 65.0% IN P16, 61.6% IN RIZ1 AND 60.0% IN MGMT. METHYLATION OF THE 6 GENES WAS MORE FREQUENT IN HCC THAN THAT IN ADJACENT TISSUES (P < 0.05). THE METHYLATION RATE OF MGMT, GSTP1 AND RIZ1 IN THE ADJACENT TISSUES WAS 41.6%, 40.0% AND 25.0%, RESPECTIVELY, SIGNIFICANTLY HIGHER THAN THAT IN CIRRHOTIC LIVER (P < 0.05). P16 METHYLATION WAS MORE FREQUENTLY OBSERVED IN HCC IN ELDERLY PATIENTS. THE FREQUENCY OF MGMT METHYLATION WAS TENDED TO BE HIGHER IN GIANT HCC THAN THAT IN THE OTHER TYPES OF HCC. PATIENTS WITH MGMT METHYLATION IN THE TUMOR WERE FOUND TO HAVE A SHORTER DISEASE FREE SURVIVAL. CONCLUSION: DIFFERENT FREQUENCY OF METHYLATION IN HEPATOCELLULAR CARCINOMAS, ADJACENT LIVER TISSUES AND CIRRHOTIC LIVERS IMPLIES THAT EPIGENETIC ALTERATION IN THE HEPATOCELLULAR CARCINOGENESIS MAY BE A GRADUALLY PROGRESSIVE PROCESS. METHYLATION STATUS OF MGMT, GSTP1 AND RIZ1 MAY BE PROMISING IN RISK ASSESSMENT OF HEPATOCELLULAR CARCINOMA AND IN EARLY DIAGNOSIS. FURTHERMORE, MGMT METHYLATION MIGHT BE ALSO USED AS A POTENTIAL PROGNOSTIC BIOMARKER FOR HEPATOCELLULAR CARCINOMA PATIENTS.	2008	
                                                                                                                                                              
19 3444  32 HYPERMETHYLATION OF E-CADHERIN IN LEUKEMIA. E-CADHERIN GENE IS OFTEN TERMED A "METASTASIS SUPPRESSOR" GENE BECAUSE THE E-CADHERIN PROTEIN CAN SUPPRESS TUMOR CELL INVASION AND METASTASIS. INACTIVATION OF THE E-CADHERIN GENE OCCURS IN UNDIFFERENTIATED SOLID TUMORS BY BOTH GENETIC AND EPIGENETIC MECHANISMS; HOWEVER, THE ROLE OF E-CADHERIN IN HEMATOLOGIC MALIGNANCIES IS ONLY NOW BEING RECOGNIZED. E-CADHERIN EXPRESSION IS ESSENTIAL FOR ERYTHROBLAST AND NORMOBLAST MATURATION, YET EXPRESSION IS REDUCED OR ABSENT IN LEUKEMIC BLAST CELLS. THIS STUDY EXAMINED THE MESSENGER RNA (MRNA) AND PROTEIN EXPRESSION OF THE E-CADHERIN GENE IN BONE MARROW AND BLOOD SAMPLES FROM NORMAL DONORS AND PATIENTS WITH LEUKEMIA. WE FOUND THAT ALL NORMAL DONOR SAMPLES EXPRESSED E-CADHERIN MRNA, WHEREAS BOTH SAMPLES OF ACUTE MYELOGENOUS LEUKEMIA AND CHRONIC LYMPHOCYTIC LEUKEMIA HAD A SIGNIFICANT REDUCTION OR ABSENCE OF EXPRESSION. HOWEVER, NORMAL BLAST COUNTERPARTS EXPRESSED ONLY A LOW LEVEL OF E-CADHERIN SURFACE PROTEIN. SODIUM BISULPHITE GENOMIC SEQUENCING WAS USED TO FULLY CHARACTERIZE THE METHYLATION PATTERNS OF THE CPG ISLAND ASSOCIATED WITH THE E-CADHERIN GENE PROMOTER IN THOSE SAMPLES WITH MATCHED DNA. ALL OF THE NORMAL CONTROL SAMPLES WERE ESSENTIALLY UNMETHYLATED; HOWEVER, 14 OF 18 (78%) OF THE LEUKEMIA SAMPLES HAD ABNORMAL HYPERMETHYLATION OF THE E-CADHERIN CPG ISLAND. IN FACT BOTH ALLELES OF THE E-CADHERIN GENE WERE OFTEN HYPERMETHYLATED. WE CONCLUDE THE E-CADHERIN GENE IS A COMMON TARGET FOR HYPERMETHYLATION IN HEMATOLOGIC MALIGNANCIES.	2000	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
20  817  46 CHARACTERISTIC PATTERNS OF ALTERED DNA METHYLATION PREDICT EMERGENCE OF HUMAN HEPATOCELLULAR CARCINOMA. WE AIMED TO IDENTIFY THE SPECIFIC SUBSET OF TUMOR SUPPRESSOR GENES (TSGS) THAT ARE METHYLATION-SILENCED DURING THE EARLIEST STEPS OF HEPATOCARCINOGENESIS, AND TO FURTHER EVALUATE WHETHER THESE GENES CAN SERVE AS PREDICTIVE BIOMARKERS OF HEPATOCELLULAR CARCINOMA (HCC) EMERGENCE. A TOTAL OF 482 LIVER TISSUES INCLUDING 177 PAIRS OF HCCS AND MATCHED NONTUMOR LIVERS AND 128 LIVER BIOPSIES FROM CHRONIC HEPATITIS C (CHC) PATIENTS WERE ANALYZED FOR QUANTITATIVE METHYLATION ANALYSIS IN 24 TSG PROMOTERS AND THREE MINT LOCI. THE TUMORS WERE CLASSIFIED AS EARLY, LESS-PROGRESSED, AND HIGHLY PROGRESSED HCCS USING HISTOLOGY AND RADIOLOGICAL APPROACHES. A SUBSET OF TSGS THAT HARBORED DISTINCTLY HIGH LEVELS OF METHYLATION IN EARLY HCCS WERE SELECTED. BASED ON THE METHYLATION PROFILES OF THESE GENES, KAPLAN-MEIER ANALYSES WERE PERFORMED TO DETERMINE TIME-TO-HCC OCCURRENCE IN CHC PATIENTS. SUBSEQUENTLY, MULTIVARIATE ANALYSIS WAS PERFORMED USING AGE, GENDER, FIBROSIS STAGE, AND NUMBER OF METHYLATED TSGS AS COVARIATES. AMONG TSGS ANALYZED, A SUBSET OF EIGHT TSGS (HIC1, GSTP1, SOCS1, RASSF1, CDKN2A, APC, RUNX3, AND PRDM2) DEMONSTRATED A DISTINCT CLUSTER BY HIERARCHICAL CLUSTERING AND RECEIVER OPERATING CHARACTERISTIC ANALYSES. THIS SUBSET OF TSGS SHOWED SIGNIFICANTLY HIGHER METHYLATION LEVELS IN THE EARLY HCCS (P < 0.0001). IN THE CHC PATIENTS, METHYLATION FREQUENCIES IN THESE TSGS WERE ASSOCIATED WITH SHORTER TIME-TO-HCC OCCURRENCE (P < 0.0001), AND NUMBER OF METHYLATED GENES WAS AN INDEPENDENT RISK FACTOR FOR HCC (HAZARD RATIO = 5.21, 95% CONFIDENCE INTERVAL = 2.25-11.76, P = 0.0002). CONCLUSION: EPIGENETIC INACTIVATION OF A SUBSET OF TSGS PLAYS A CRITICAL ROLE IN THE EARLIEST STEPS OF HEPATOCARCINOGENESIS. FURTHERMORE, EPIGENETIC INACTIVATION OF THESE GENES IN CHC PROVIDES A PROGNOSTIC VALUE FOR DETERMINING THE RISK FOR DEVELOPING HCC LATER IN LIFE.	2012