1 6596 152 TUMOR-SUPPRESSIVE MIR-192-5P HAS PROGNOSTIC VALUE IN PANCREATIC DUCTAL ADENOCARCINOMA. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS CHARACTERIZED BY FAST TUMOR PROGRESSION AND DIAGNOSIS AT ADVANCED, INOPERABLE STAGES. PREVIOUS STUDIES COULD DEMONSTRATE AN INVOLVEMENT OF MIR-192-5P IN EPIGENETIC REGULATION OF VISCERAL CARCINOMAS. DUE TO CONTRADICTORY RESULTS, HOWEVER, THE CLINICAL UTILITY OF MIR-192-5P IN PDAC HAS YET TO BE DETERMINED. MIR-192-5P EXPRESSION WAS ANALYZED BY RT-QRT-PCR IN HUMAN PDAC AND BENIGN TISSUE (N = 78), BLOOD SERUM (N = 81) AND SERUM EXOSOMES (N = 74), AS WELL AS IN PDAC CELL LINES (N = 5), CHEMORESISTANT CELL CLONES (N = 2), AND PANCREATIC DUCT CELL LINE H6C7. ANALYSIS OF EMT-ASSOCIATED (EPITHELIAL-TO-MESENCHYMAL TRANSITION) PROTEINS WAS PERFORMED BY IMMUNOHISTOCHEMISTRY AND WESTERN BLOT. MIR-192-5P WAS DEREGULATED IN PDAC AS COMPARED TO HEALTHY CONTROLS (HCS), WITH DOWNREGULATION IN MACRODISSECTED TISSUE (P < 0.001) AND UPREGULATION IN BLOOD SERUM OF PDAC UICC (UNION FOR INTERNATIONAL CANCER CONTROL) STAGE IV (P = 0.016) AND SERUM EXOSOMES OF PDAC UICC STAGES II TO IV (P < 0.001). MIR-192-5P EXPRESSION IN TUMOR TISSUE WAS SIGNIFICANTLY LOWER AS COMPARED TO CORRESPONDING PERITUMORAL TISSUE (PDAC UICC STAGE II: P < 0.001; PDAC UICC STAGE III: P = 0.024), WHILE EMT MARKERS ZEB1 AND ZEB2 WERE MORE FREQUENTLY EXPRESSED IN TUMOR TISSUE AS COMPARED TO PERITUMORAL TISSUE, HCS, AND CHRONIC PANCREATITIS. TISSUE-DERIVED (AUC OF 0.86; P < 0.0001) AND EXOSOMAL (AUC OF 0.83; P = 0.0004) MIR-192-5P COULD DIFFERENTIATE BETWEEN PDAC AND HCS WITH GOOD ACCURACY. FURTHERMORE, HIGH EXPRESSION OF MIR-192-5P IN PDAC TISSUE OF CURATIVELY RESECTED PDAC PATIENTS CORRELATED WITH PROLONGED OVERALL AND RECURRENCE-FREE SURVIVAL IN MULTIVARIATE ANALYSIS. IN VITRO, MIR-192-5P WAS DOWNREGULATED IN GEMCITABINE-RESISTANT CELL CLONES OF ASPC-1 (P = 0.029). TRANSIENT TRANSFECTION OF MIA PACA-2 CELLS WITH MIR-192-5P MIMIC RESULTED IN DOWNREGULATION OF ZEB2. MIR-192-5P SEEMS TO POSSESS A TUMOR-SUPPRESSIVE ROLE AND HIGH POTENTIAL AS A DIAGNOSTIC AND PROGNOSTIC MARKER IN PDAC. 2020 2 779 30 CELL-FREE DNA PROMOTER HYPERMETHYLATION AS A DIAGNOSTIC MARKER FOR PANCREATIC DUCTAL ADENOCARCINOMA - AN EXTERNAL VALIDATION STUDY. BACKGROUND: WE RECENTLY IDENTIFIED A DIAGNOSTIC PREDICTION MODEL BASED ON PROMOTER HYPERMETHYLATION OF EIGHT SELECTED GENES IN PLASMA CELL-FREE (CF) DNA, WHICH SHOWED PROMISING RESULTS AS A DIAGNOSTIC BIOMARKER FOR PANCREATIC DUCTAL ADENOCARCINOMA (PDAC). THE AIM OF THE PRESENT STUDY WAS TO VALIDATE THIS BIOMARKER PROFILE IN AN EXTERNAL PATIENT COHORT AND EXAMINE ANY ADDITIONAL EFFECT OF SERUM CA 19-9. METHODS: PATIENTS WITH PDAC (N = 346, STAGE I-IV) AND CHRONIC PANCREATITIS (N = 25) WERE INCLUDED. METHYLATION-SPECIFIC PCR OF A 28-GENE PANEL WAS PERFORMED ON SERUM CFDNA SAMPLES. THE PREVIOUSLY DEVELOPED DIAGNOSTIC PREDICTION MODEL (AGE>65 YEARS, BMP3, RASSF1A, BNC1, MESTV2, TFPI2, APC, SFRP1 AND SFRP2) WAS VALIDATED ALONE AND IN COMBINATION WITH SERUM CA 19-9 IN THIS EXTERNAL PATIENT COHORT. RESULTS: PATIENTS WITH PDAC HAD A HIGHER NUMBER OF HYPERMETHYLATED GENES (MEAN 8.11, 95% CI 7.70-8.52) THAN PATIENTS WITH CHRONIC PANCREATITIS (MEAN 5.60, 95% CI 4.42-6.78, P = 0.011). VALIDATION OF THE DIAGNOSTIC PREDICTION MODEL YIELDED AN AUC OF 0.77 (95% CI 0.69-0.84). THE COMBINATION OF SERUM CA 19-9 AND OUR TEST HAD AN AUC OF 0.93 (95% CI 0.89-0.96) IN THE PRIMARY STUDY AND 0.85 (95% CI 0.79-0.91) IN THE VALIDATION STUDY. CONCLUSION: IN THIS VALIDATION STUDY, PDAC WAS ASSOCIATED WITH A HIGHER NUMBER OF HYPERMETHYLATED GENES IN SERUM CFDNA THAN CHRONIC PANCREATITIS. OUR DIAGNOSTIC TEST WAS SUPERIOR TO THE PREDICTIVE VALUE OF SERUM CA 19-9 ALONE IN BOTH THE PRIMARY AND THE VALIDATION STUDY. THE COMBINATION OF OUR TEST WITH CA 19-9 MAY SERVE AS A CLINICALLY USEFUL DIAGNOSTIC BIOMARKER FOR PDAC. 2021 3 1742 35 EARLY EPIGENETIC DOWNREGULATION OF WNK2 KINASE DURING PANCREATIC DUCTAL ADENOCARCINOMA DEVELOPMENT. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS USUALLY INCURABLE. CONTRARY TO GENETIC MECHANISMS INVOLVED IN PDAC PATHOGENESIS, EPIGENETIC ALTERATIONS ARE ILL DEFINED. HERE, WE DETERMINE THE CONTRIBUTION OF EPIGENETICALLY SILENCED GENES TO THE DEVELOPMENT OF PDAC. WE ANALYZED ENRICHED, HIGHLY METHYLATED DNAS FROM PDACS, CHRONIC PANCREATITIS (CP) AND NORMAL TISSUES USING CPG ISLAND MICROARRAYS AND IDENTIFIED WNK2 AS A PROMINENT CANDIDATE TUMOR SUPPRESSOR GENE BEING DOWNREGULATED EARLY IN PDAC DEVELOPMENT. WNK2 WAS FURTHER INVESTIGATED IN TISSUE MICROARRAYS, METHYLATION ANALYSIS OF EARLY PANCREATIC INTRAEPITHELIAL NEOPLASIA (PANIN), MOUSE MODELS FOR PDAC AND PANCREATITIS, RE-EXPRESSION STUDIES AFTER DEMETHYLATION, AND CELL GROWTH ASSAYS USING WNK2 OVEREXPRESSION. DEMETHYLATION ASSAYS CONFIRMED THE LINK BETWEEN METHYLATION AND EXPRESSION. WNK2 HYPERMETHYLATION WAS HIGHER IN TUMOR THAN IN SURROUNDING INFLAMED TISSUES AND WAS OBSERVED IN PANIN LESIONS AS WELL AS IN A PDAC MOUSE MODEL. WNK2 MRNA AND PROTEIN EXPRESSIONS WERE LOWER IN PDAC AND CP COMPARED WITH NORMAL TISSUES BOTH IN PATIENTS AND MOUSE MODELS. OVEREXPRESSION OF WNK2 LED TO REDUCED CELL GROWTH, AND WNK2 EXPRESSION IN TISSUES CORRELATED NEGATIVELY WITH PERK1/2 EXPRESSION, A DOWNSTREAM TARGET OF WNK2 RESPONSIBLE FOR CELL PROLIFERATION. DOWNREGULATION OF WNK2 BY PROMOTER HYPERMETHYLATION OCCURS EARLY IN PDAC PATHOGENESIS AND MAY SUPPORT TUMOR CELL GROWTH VIA THE ERK-MAPK PATHWAY. 2014 4 1064 47 CLINICAL SIGNIFICANCE OF PROMOTER METHYLATION STATUS OF TUMOR SUPPRESSOR GENES IN CIRCULATING DNA OF PANCREATIC CANCER PATIENTS. INTRODUCTION: PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS A VERY AGGRESSIVE CANCER. THERE ARE VARIOUS SUB-CELLULAR EVENTS (BOTH GENETIC AND EPIGENETIC) THAT GET DYSREGULATED LEADING TO TUMORIGENESIS. METHYLATION IN PROMOTERS OF TUMOR SUPPRESSOR GENES IS ONE OF THESE EPIGENETIC PHENOMENA CONTRIBUTING TO THE PATHOGENESIS OF CANCER. GENES ANALYZED FOR PROMOTER METHYLATION STATUS IN THIS STUDY NAMELY SPARC (SECRETED PROTEIN ACIDIC AND RICH IN CYSTEINE, UCHL1 (UBIQUITIN CARBOXY-TERMINAL HYDROLASE L1), NPTX2 (NEURONAL PENTRAXIN 2), PENK (PROENKEPHALIN) HAD BEEN STUDIED IN PANCREATIC CANCER, BUT THERE IS A NEED TO CHECK METHYLATION IN THESE GENES AS CIRCULATORY NON-INVASIVE MARKERS. THIS STUDY ANALYZED THE ABSOLUTE QUANTIFICATION OF METHYLATION LEVELS OF SPARC, UCHL1, PENK, AND NPTX2 GENES PROMOTERS IN PDAC PATIENTS AS WELL AS IN CHRONIC PANCREATITIS (CP) PATIENTS AND HEALTHY SUBJECTS (HC) AND EVALUATED ITS CLINICAL SIGNIFICANCE IN PDAC. MATERIALS AND METHODS: THE STUDY INCLUDED 65 PDAC PATIENTS, 25 CP PATIENTS, AND 25 HEALTHY CONTROLS. DNA WAS EXTRACTED FROM THEIR PLASMA SAMPLES AND SUBSEQUENTLY GIVEN BISULFITE TREATMENT. ABSOLUTE QUANTIZATION OF METHYLATED AND UNMETHYLATED COPIES OF GENE PROMOTERS OF ALL THE FOUR GENES WAS PERFORMED USING REAL-TIME PCR (SYBR GREEN) BY THE STANDARD CURVE METHOD. METHYLATION LEVELS WERE EXPRESSED AS METHYLATION INDEX (MI) FOR EACH GENE IN EACH PATIENT. MI WAS CALCULATED FROM ABSOLUTE COPY NUMBERS AS FOLLOWS: MI-METHYLATED COPY NUMBER/METHYLATED COPY NUMBER + UNMETHYLATED COPY NUMBER). THESE INDICES WERE USED TO COMPARE GENE METHYLATION LEVELS WITHIN DIFFERENT GROUPS AND TO CORRELATE WITH CLINICOPATHOLOGICAL FEATURES AND SURVIVAL OF PANCREATIC CANCER PATIENTS. AN APPROPRIATE STATISTICAL ANALYSIS WAS APPLIED. RESULTS: METHYLATION INDICES FOR ALL THE FOUR GENES IN PDAC CASES WERE FOUND TO BE SIGNIFICANTLY HIGHER AS COMPARED TO THAT IN HEALTHY INDIVIDUALS. SPARC MI VALUES WERE FOUND TO DIFFERENTIATE EARLY-STAGE PDAC PATIENTS FROM CP PATIENTS. PDAC PATIENTS WITH THE METASTASIZED DISEASE AND STAGE IV DISEASE WERE FOUND TO HAVE HIGH MI FOR THE SPARC GENE AS WELL AS FOR THE NPTX2 GENE, WHILE A HIGHER UCHL1 METHYLATION INDEX WAS FOUND TO CORRELATE WITH AN ADVANCED STAGE OF THE DISEASE. HIGHER MI VALUES FOR SPARC AND NPTX2 GENES WERE FOUND TO ASSOCIATE WITH POOR SURVIVAL IN PATIENTS WITH PDAC. CONCLUSION: METHYLATION LOAD IN THE FORM OF MI FOR EACH OF THE FOUR GENES ASSESSED IN PLASMA MAY EMERGE AS A NON-INVASIVE BIOMARKER TO DIFFERENTIATE PANCREATIC CANCER FROM HEALTHY INDIVIDUALS. BUT ONLY SPARC AND NPTX2 HYPERMETHYLATION WERE ABLE TO DISTINGUISH PANCREATIC CANCER FROM CHRONIC PANCREATITIS. ASSOCIATION OF ABERRANT METHYLATION IN SPARC AND NPTX2 GENE WITH METASTASIS AND POOR SURVIVAL OF PATIENTS SUGGEST THE ROLE OF METHYLATION IN THESE GENES AS PROGNOSTIC MARKERS. 2020 5 4334 27 MICRORNAS: NOVEL DIAGNOSTIC AND THERAPEUTIC TOOLS FOR PANCREATIC DUCTAL ADENOCARCINOMA? PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS KNOWN FOR ITS VERY POOR OVERALL PROGNOSIS, MAKING TOOLS FOR EARLY DIAGNOSIS AND NEW THERAPEUTIC MODALITIES URGENTLY NEEDED. MICRORNAS (MIRNAS), ENDOGENOUS NONCODING RNA MOLECULES OF APPROXIMATELY 22 NT, HAVE GAINED ATTENTION AS AN EPIGENETIC COMPONENT INVOLVED IN THE DEVELOPMENT OF MANY CANCERS, INCLUDING PDAC. MIRNA EXPRESSION PROFILES OF VARYING PANCREATIC TISSUES HAVE IDENTIFIED A NUMBER OF DIFFERENTIALLY EXPRESSED MIRNAS AND SEEM TO BE ABLE TO DIFFERENTIATE BETWEEN THREE TISSUES OF CLINICAL IMPORTANCE: NORMAL PANCREAS, CHRONIC PANCREATITIS, AND PDAC. THIS ARTICLE GATHERS OUR CURRENT KNOWLEDGE OF DIFFERENTIALLY EXPRESSED MIRNAS IN PANCREATIC TISSUES WITH RELEVANCE TO PDAC AND PRESENTS POTENTIAL DIAGNOSTIC AND THERAPEUTIC OPPORTUNITIES. 2009 6 1741 40 EARLY EPIGENETIC DOWNREGULATION OF MICRORNA-192 EXPRESSION PROMOTES PANCREATIC CANCER PROGRESSION. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS CHARACTERIZED BY VERY EARLY METASTASIS, SUGGESTING THE HYPOTHESIS THAT METASTASIS-ASSOCIATED CHANGES MAY OCCUR PRIOR TO ACTUAL TUMOR FORMATION. IN THIS STUDY, WE IDENTIFIED MIR-192 AS AN EPIGENETICALLY REGULATED SUPPRESSOR GENE WITH PREDICTIVE VALUE IN THIS DISEASE. MIR-192 WAS DOWNREGULATED BY PROMOTER METHYLATION IN BOTH PDAC AND CHRONIC PANCREATITIS, THE LATTER OF WHICH IS A MAJOR RISK FACTOR FOR THE DEVELOPMENT OF PDAC. FUNCTIONAL STUDIES IN VITRO AND IN VIVO IN MOUSE MODELS OF PDAC SHOWED THAT OVEREXPRESSION OF MIR-192 WAS SUFFICIENT TO REDUCE CELL PROLIFERATION AND INVASION. MECHANISTIC ANALYSES CORRELATED CHANGES IN MIR-192 PROMOTER METHYLATION AND EXPRESSION WITH EPITHELIAL-MESENCHYMAL TRANSITION. CELL PROLIFERATION AND INVASION WERE LINKED TO ALTERED EXPRESSION OF THE MIR-192 TARGET GENE SERPINE1 THAT IS ENCODING THE PROTEIN PLASMINOGEN ACTIVATOR INHIBITOR-1 (PAI-1), AN ESTABLISHED REGULATOR OF THESE PROPERTIES IN PDAC CELLS. NOTABLY, OUR DATA SUGGESTED THAT INVASIVE CAPACITY WAS ALTERED EVEN BEFORE NEOPLASTIC TRANSFORMATION OCCURRED, AS TRIGGERED BY MIR-192 DOWNREGULATION. OVERALL, OUR RESULTS HIGHLIGHTED A ROLE FOR MIR-192 IN EXPLAINING THE EARLY METASTATIC BEHAVIOR OF PDAC AND SUGGESTED ITS RELEVANCE AS A TARGET TO DEVELOP FOR EARLY DIAGNOSTICS AND THERAPY. CANCER RES; 76(14); 4149-59. (C)2016 AACR. 2016 7 6539 35 TRANSCRIPTIONAL VARIATIONS IN THE WIDER PERITUMORAL TISSUE ENVIRONMENT OF PANCREATIC CANCER. TRANSCRIPTIONAL PROFILING WAS PERFORMED ON 452 RNA PREPARATIONS ISOLATED FROM VARIOUS TYPES OF PANCREATIC TISSUE FROM TUMOUR PATIENTS AND HEALTHY DONORS, WITH A PARTICULAR FOCUS ON PERITUMORAL SAMPLES. PANCREATIC DUCTAL ADENOCARCINOMAS (PDAC) AND CYSTIC TUMOURS WERE MOST DIFFERENT IN THESE NON-TUMOROUS TISSUES SURROUNDING THEM, WHEREAS THE ACTUAL TUMOURS EXHIBITED RATHER SIMILAR TRANSCRIPT PATTERNS. THE ENVIRONMENT OF CYSTIC TUMOURS WAS TRANSCRIPTIONALLY NEARLY IDENTICAL TO NORMAL PANCREAS TISSUE. IN CONTRAST, THE TISSUE AROUND PDAC BEHAVED A LOT LIKE THE TUMOUR, INDICATING SOME KIND OF FIELD DEFECT, WHILE SHOWING FAR LESS MOLECULAR RESEMBLANCE TO BOTH CHRONIC PANCREATITIS AND HEALTHY TISSUE. THIS SUGGESTS THAT THE MAJOR PATHOGENIC DIFFERENCE BETWEEN CYSTIC AND DUCTAL TUMOURS MAY BE DUE TO THEIR CELLULAR ENVIRONMENT RATHER THAN THE FEW VARIATIONS BETWEEN THE TUMOURS. LACK OF CORRELATION BETWEEN DNA METHYLATION AND TRANSCRIPT LEVELS MAKES IT UNLIKELY THAT THE OBSERVED FIELD DEFECT IN THE PERITUMORAL TISSUE OF PDAC IS CONTROLLED TO A LARGE EXTENT BY SUCH EPIGENETIC REGULATION. FUNCTIONALLY, A STRIKINGLY LARGE NUMBER OF AUTOPHAGY-RELATED TRANSCRIPTS WAS CHANGED IN BOTH PDAC AND ITS PERITUMORAL TISSUE, BUT NOT IN OTHER PANCREATIC TUMOURS. A TRANSCRIPTION SIGNATURE OF 15 AUTOPHAGY-RELATED GENES WAS ESTABLISHED THAT PERMITS A PROGNOSIS OF SURVIVAL WITH HIGH ACCURACY AND INDICATES THE ROLE OF AUTOPHAGY IN TUMOUR BIOLOGY. 2018 8 507 44 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 9 1435 35 DIFFERENTIAL METHYLATION LANDSCAPE OF PANCREATIC DUCTAL ADENOCARCINOMA AND ITS PRECANCEROUS LESIONS. BACKGROUND: PANCREATIC CANCER IS ONE OF THE MOST LETHAL DISEASES WITH AN INCIDENCE ALMOST EQUAL TO THE MORTALITY. IN ADDITION TO HAVING GENETIC CAUSES, CANCER CAN ALSO BE CONSIDERED AN EPIGENETIC DISEASE. DNA METHYLATION IS THE PREMIER EPIGENETIC MODIFICATION AND PATTERNS OF ABERRANT DNA METHYLATION ARE RECOGNIZED TO BE A COMMON HALLMARK OF HUMAN TUMOR. IN THE MULTISTAGE CARCINOGENESIS OF PANCREAS STARTING FROM PRECANCEROUS LESIONS TO PANCREATIC DUCTAL ADENOCARCINOMA (PDAC), THE EPIGENETIC CHANGES PLAY A SIGNIFICANT ROLE. DATA SOURCES: RELEVANT STUDIES FOR THIS REVIEW WERE DERIVED VIA AN EXTENSIVE LITERATURE SEARCH IN PUBMED VIA USING VARIOUS KEYWORDS SUCH AS PANCREATIC DUCTAL ADENOCARCINOMA, PRECANCEROUS LESIONS, METHYLATION PROFILE, EPIGENETIC BIOMARKERS THAT ARE RELEVANT DIRECTLY OR CLOSELY ASSOCIATED WITH THE CONCERNED AREA OF OUR INTEREST. THE LITERATURE SEARCH WAS INTENSIVELY DONE CONSIDERING A TIME FRAME OF 20 YEARS (1998-2018). RESULT: IN THIS REVIEW WE HAVE HIGHLIGHTED THE HYPERMETHYLATION AND HYPOMETHYLATION OF THE PRECANCEROUS PDAC LESIONS (PANCREATIC INTRA-EPITHELIAL NEOPLASIA, INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM, MUCINOUS CYSTIC NEOPLASM AND CHRONIC PANCREATITIS) AND PDAC ALONG WITH THE POTENTIAL BIOMARKERS. WE HAVE ALSO ACHIEVED THE EARLY EPIGENETIC DRIVER THAT LEADS TO PROGRESSION FROM PRECANCEROUS LESIONS TO PDAC. A BUNCH OF EPIGENETIC DRIVER GENES LEADS TO PROGRESSION OF PRECANCEROUS LESIONS TO PDAC (PPENK, APC, P14/5/16/17, HMLH1 AND MGMT) ARE ALSO DOCUMENTED. WE SUMMARIZED THE IMPORTANCE OF THESE OBSERVATIONS IN THERAPEUTICS AND DIAGNOSIS OF PDAC HENCE IDENTIFYING THE POTENTIAL USE OF EPIGENETIC BIOMARKERS IN EPIGENETIC TARGETED THERAPY. EPIGENETIC INACTIVATION OCCURS BY HYPERMETHYLATION OF CPG ISLANDS IN THE PROMOTER REGIONS OF TUMOR SUPPRESSOR GENES. WE LISTED ALL HYPER- AND HYPOMETHYLATION OF CPG ISLANDS OF SEVERAL GENES IN PDAC INCLUDING ITS PRECANCEROUS LESIONS. CONCLUSIONS: THE CONCEPT OF THE REVIEW WOULD HELP TO UNDERSTAND THEIR BIOLOGICAL EFFECTS, AND TO DETERMINE WHETHER THEY MAY BE SUCCESSFULLY COMBINED WITH OTHER EPIGENETIC DRUGS. HOWEVER, WE NEED TO CONTINUE OUR RESEARCH TO DEVELOP MORE SPECIFIC DNA-DEMETHYLATING AGENTS, WHICH ARE THE TARGETS FOR HYPERMETHYLATED CPG METHYLATION SITES. 2020 10 778 30 CELL-FREE DNA METHYLATION: THE NEW FRONTIERS OF PANCREATIC CANCER BIOMARKERS' DISCOVERY. PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) IS AMONG THE MOST LETHAL CANCER TYPES WORLD-WIDE. ITS HIGH MORTALITY IS RELATED TO THE DIFFICULTY IN THE DIAGNOSIS, WHICH OFTEN OCCURS WHEN THE DISEASE IS ALREADY ADVANCED. AS OF TODAY, NO EARLY DIAGNOSTIC TESTS ARE AVAILABLE, WHILE ONLY A LIMITED NUMBER OF PROGNOSTIC TESTS HAVE REACHED CLINICAL PRACTICE. THE MAIN REASON IS THE LACK OF RELIABLE BIOMARKERS THAT ARE ABLE TO CAPTURE THE EARLY DEVELOPMENT OR THE PROGRESSION OF THE DISEASE. HENCE, THE DISCOVERY OF BIOMARKERS FOR EARLY DIAGNOSIS OR PROGNOSIS OF PDAC REMAINS, DE FACTO, AN UNMET NEED. AN INCREASING NUMBER OF STUDIES HAS SHOWN THAT CELL-FREE DNA (CFDNA) METHYLATION ANALYSIS REPRESENTS A PROMISING NON-INVASIVE APPROACH FOR THE DISCOVERY OF BIOMARKERS WITH DIAGNOSTIC OR PROGNOSTIC POTENTIAL. IN PARTICULAR, CFDNA METHYLATION COULD BE UTILIZED FOR THE IDENTIFICATION OF DISEASE-SPECIFIC SIGNATURES IN PRE-NEOPLASTIC LESIONS OR CHRONIC PANCREATITIS (CP), REPRESENTING A SENSITIVE AND NON-INVASIVE METHOD OF EARLY DIAGNOSIS OF PDAC. IN THIS REVIEW, WE WILL DISCUSS THE ADVANTAGES AND PITFALLS OF CFDNA METHYLATION STUDIES. FURTHER, WE WILL PRESENT THE CURRENT ADVANCES IN THE DISCOVERY OF PANCREATIC CANCER BIOMARKERS WITH EARLY DIAGNOSTIC OR PROGNOSTIC POTENTIAL, FOCUSING ON PANCREAS-SPECIFIC (E.G., CUX2 OR REG1A) OR ABNORMAL (E.G., ADAMTS1 OR BNC1) CFDNA METHYLATION SIGNATURES IN HIGH RISK PRE-NEOPLASTIC CONDITIONS AND PDAC. 2019 11 6132 40 THE EPIGENETIC REGULATORS BMI1 AND RING1B ARE DIFFERENTIALLY REGULATED IN PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA. CHRONIC PANCREATITIS AND PANCREATIC DUCTAL ADENOCARCINOMA (PDAC) ARE ASSOCIATED WITH MAJOR CHANGES IN CELL DIFFERENTIATION. THESE CHANGES MAY BE AT THE BASIS OF THE INCREASED RISK FOR PDAC AMONG PATIENTS WITH CHRONIC PANCREATITIS. POLYCOMB PROTEINS ARE EPIGENETIC SILENCERS EXPRESSED IN ADULT STEM CELLS; UP-REGULATION OF POLYCOMB PROTEINS HAS BEEN REPORTED TO OCCUR IN A VARIETY OF SOLID TUMOURS SUCH AS COLON AND BREAST CANCER. WE HYPOTHESIZED THAT POLYCOMB MIGHT PLAY A ROLE IN PRENEOPLASTIC STATES IN THE PANCREAS AND IN TUMOUR DEVELOPMENT/PROGRESSION. TO TEST THESE IDEAS, WE DETERMINED THE EXPRESSION OF PRC1 COMPLEX PROTEINS (BMI1 AND RING1B) DURING PANCREATIC DEVELOPMENT AND IN PANCREATIC TISSUE FROM MOUSE MODELS OF DISEASE: ACUTE AND CHRONIC PANCREATIC INJURY, DUCT LIGATION, AND IN K-RAS(G12V) CONDITIONAL KNOCK-IN AND CAERULEIN-TREATED K-RAS(G12V) MICE. THE STUDY WAS EXTENDED TO HUMAN PANCREATIC TISSUE SAMPLES. TO OBTAIN MECHANISTIC INSIGHTS, BMI1 EXPRESSION IN CELLS UNDERGOING IN VITRO EXOCRINE CELL METAPLASIA AND THE EFFECTS OF BMI1 DEPLETION IN AN ACINAR CANCER CELL LINE WERE STUDIED. WE FOUND THAT BMI1 AND RING1B ARE EXPRESSED IN PANCREATIC EXOCRINE PRECURSOR CELLS DURING EARLY DEVELOPMENT AND IN DUCTAL AND ISLET CELLS-BUT NOT ACINAR CELLS-IN THE ADULT PANCREAS. BMI1 EXPRESSION WAS INDUCED IN ACINAR CELLS DURING ACUTE INJURY, IN ACINAR-DUCTAL METAPLASTIC LESIONS, AS WELL AS IN PANCREATIC INTRAEPITHELIAL NEOPLASIA (PANIN) AND PDAC. IN CONTRAST, RING1B EXPRESSION WAS ONLY SIGNIFICANTLY AND PERSISTENTLY UP-REGULATED IN HIGH-GRADE PANINS AND IN PDAC. BMI1 KNOCKDOWN IN CULTURED ACINAR TUMOUR CELLS LED TO CHANGES IN THE EXPRESSION OF VARIOUS DIGESTIVE ENZYMES. OUR RESULTS SUGGEST THAT BMI1 AND RING1B ARE MODULATED IN PANCREATIC DISEASES AND COULD CONTRIBUTE DIFFERENTLY TO TUMOUR DEVELOPMENT. 2009 12 780 46 CELL-FREE DNA PROMOTER HYPERMETHYLATION IN PLASMA AS A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA. BACKGROUND: PANCREATIC CANCER HAS A 5-YEAR SURVIVAL RATE OF ONLY 5-7%. DIFFICULTIES IN DETECTING PANCREATIC CANCER AT EARLY STAGES RESULTS IN THE HIGH MORTALITY AND SUBSTANTIATES THE NEED FOR ADDITIONAL DIAGNOSTIC TOOLS. SURGERY IS THE ONLY CURATIVE TREATMENT AND UNFORTUNATELY ONLY POSSIBLE IN LOCALIZED TUMOURS. A DIAGNOSTIC BIOMARKER FOR PANCREATIC CANCER WILL HAVE A MAJOR IMPACT ON PATIENT SURVIVAL BY FACILITATING EARLY DETECTION AND THE POSSIBILITY FOR CURATIVE TREATMENT. DNA PROMOTER HYPERMETHYLATION IS A MECHANISM OF EARLY CARCINOGENESIS, WHICH CAN CAUSE INACTIVATION OF TUMOUR SUPPRESSOR GENES. THE AIM OF THIS STUDY WAS TO EXAMINE PROMOTER HYPERMETHYLATION IN A PANEL OF SELECTED GENES FROM CELL-FREE DNA, AS A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA. METHODS: PATIENTS WITH SUSPECTED OR BIOPSY-VERIFIED PANCREATIC CANCER WERE INCLUDED PROSPECTIVELY AND CONSECUTIVELY. PATIENTS WITH CHRONIC/ACUTE PANCREATITIS WERE INCLUDED AS ADDITIONAL BENIGN CONTROL GROUPS. BASED ON AN OPTIMIZED ACCELERATED BISULFITE TREATMENT PROTOCOL, METHYLATION-SPECIFIC PCR OF A 28 GENE PANEL WAS PERFORMED ON PLASMA SAMPLES. A DIAGNOSTIC PREDICTION MODEL WAS DEVELOPED BY MULTIVARIABLE LOGISTIC REGRESSION ANALYSIS USING BACKWARD STEPWISE ELIMINATION. RESULTS: PATIENTS WITH PANCREATIC ADENOCARCINOMA (N = 95), CHRONIC PANCREATITIS (N = 97) AND ACUTE PANCREATITIS (N = 59) AND PATIENTS SCREENED, BUT NEGATIVE FOR PANCREATIC ADENOCARCINOMA (N = 27), WERE INCLUDED. THE DIFFERENCE IN MEAN NUMBER OF METHYLATED GENES IN THE CANCER GROUP (8.41 (95% CI 7.62-9.20)) VS THE TOTAL CONTROL GROUP (4.74 (95% CI 4.40-5.08)) WAS HIGHLY SIGNIFICANT (P < 0.001). A DIAGNOSTIC PREDICTION MODEL (AGE >65, BMP3, RASSF1A, BNC1, MESTV2, TFPI2, APC, SFRP1 AND SFRP2) HAD AN AREA UNDER THE CURVE OF 0.86 (SENSITIVITY 76%, SPECIFICITY 83%). THE MODEL PERFORMANCE WAS INDEPENDENT OF CANCER STAGE. CONCLUSIONS: CELL-FREE DNA PROMOTER HYPERMETHYLATION HAS THE POTENTIAL TO BE A DIAGNOSTIC MARKER FOR PANCREATIC ADENOCARCINOMA AND DIFFERENTIATE BETWEEN MALIGNANT AND BENIGN PANCREATIC DISEASE. THIS STUDY BRINGS US CLOSER TO A CLINICAL USEFUL DIAGNOSTIC MARKER FOR PANCREATIC CANCER, WHICH IS URGENTLY NEEDED. EXTERNAL VALIDATION IS, HOWEVER, REQUIRED BEFORE THE TEST CAN BE APPLIED IN THE CLINIC. TRIAL REGISTRATION: CLINICALTRIALS.GOV, NCT02079363. 2016 13 672 29 BRAF, KRAS AND HELICOBACTER PYLORI EPIGENETIC CHANGES-ASSOCIATED CHRONIC GASTRITIS IN EGYPTIAN PATIENTS WITH AND WITHOUT GASTRIC CANCER. WE AIMED TO STUDY MLH1 AND MGMT METHYLATION STATUS IN HELICOBACTER PYLORI-ASSOCIATED CHRONIC GASTRITIS IN EGYPTIAN PATIENTS WITH AND WITHOUT GASTRIC CANCER. 39 PATIENTS WERE INCLUDED IN OUR STUDY. THEY WERE DIVIDED INTO 2 GROUPS; PATIENTS WITHOUT (GROUP I) AND WITH GASTRIC ADENOCARCINOMA (GROUP II). PATIENTS WERE SUBJECTED TO CLINICAL EXAMINATION, ABDOMINAL ULTRASOUND AND UPPER ENDOSCOPY FOR GASTRIC BIOPSY. BIOPSIES WERE SUBJECTED TO UREASE TEST, HISTOLOGICAL EXAMINATION, AND DNA PURIFICATION. H. PYLORI, BRAF, KRAS, MLH1 AND MGMT METHYLATION WERE ASSESSED BY QUANTITATIVE PCR. DNA SEQUENCING WAS PERFORMED TO ASSESS BRAF AND KRAS GENES MUTATION. QPCR OF H. PYLORI WAS SIGNIFICANTLY HIGHER IN PATIENTS WITH ADENOCARCINOMA (GROUP II) THAN THOSE WITHOUT ADENOCARCINOMA (GROUP I); WITH A P < 0.001 AS WELL AS IN PATIENTS WITH AGE ABOVE 50 YEARS WITH A P VALUE = 0.008. BY APPLYING LOGISTIC REGRESSION ANALYSIS IT WAS REPORTED THAT THE H. PYLORI QPCR IS A SIGNIFICANT PREDICTOR TO THE ADENOCARCINOMA WITH OR = 1.025 (95 % CI: 1. 002-1.048), WITH SENSITIVITY OF 90 % AND SPECIFICITY OF 100 %. ADENOCARCINOMA PATIENTS HAD A SIGNIFICANTLY HIGHER MEAN AGE AND LEVELS OF H. PYLORI, BRAF, K-RAS, METHYLATED MGMT AND METHYLATED MLH1 THAN THOSE OF GASTRITIS PATIENTS. DNA SEQUENCE ANALYSIS OF BRAF (CODON 12) AND KRAS (CODON 600) HAD GENES MUTATION IN GASTRIC ADENOCARCINOMA VERSUS CHRONIC GASTRITIS. CONCLUSION: H. PYLORI MAY CAUSE EPIGENETIC CHANGES PREDISPOSING THE PATIENTS TO CANCER STOMACH. ESTIMATION OF H. PYLORI BY QPCR CAN BE A GOOD PREDICTOR TO ADENOCARCINOMA. BRAF AND KRAS GENES MUTATION WERE REVELED IN GASTRITIS AND ADENOCARCINOMA PATIENTS. 2016 14 6386 36 THE ROLE OF QUANTITATIVE NPTX2 HYPERMETHYLATION AS A NOVEL SERUM DIAGNOSTIC MARKER IN PANCREATIC CANCER. OBJECTIVES: THE MAJORITY OF PANCREATIC CANCERS ARE FOUND TO BE UNRESECTABLE, AND THE ONLY CHANCE FOR CURE LIES ON EARLY DETECTION AND COMPLETE RESECTION. SEVERAL GENES HAVE BEEN DISCOVERED TO BE ABERRANTLY METHYLATED IN PRIMARY PANCREATIC CANCER TISSUE, AND THIS CANCER DNA CAN BE DETECTED IN THE PLASMA. THE AIMS OF THIS STUDY WERE TO DEVELOP A NOVEL DIAGNOSTIC MARKER BASED ON EPIGENETIC CHARACTERISTICS OF PANCREATIC CANCER. METHODS: WE ENROLLED 104 PATIENTS WITH PANCREATIC CANCER, 60 WITH CHRONIC PANCREATITIS, AND 5 WITH BENIGN BILIARY STONE DISEASES. THE BLOOD SAMPLES WERE COLLECTED BEFORE SURGERY OR ANY KINDS OF TREATMENT MODALITIES. DNA WAS EXTRACTED FROM THE PLASMA OF EACH PATIENT, AND NPTX2 (NEURONAL PENTRAXIN II) CPG ISLAND HYPERMETHYLATION WAS EXAMINED QUANTITATIVELY BY REAL-TIME POLYMERASE CHAIN REACTION. RESULTS: NPTX2 HYPERMETHYLATION LEVELS WERE SIGNIFICANTLY HIGHER COMPARED WITH CHRONIC PANCREATITIS (P = 0.016). THE SENSITIVITY AND SPECIFICITY WERE 80% AND 76%, RESPECTIVELY (CUTOFF = 0.015). NPTX2 GENE HYPERMETHYLATION LEVEL WAS SIGNIFICANTLY ELEVATED IN CORRELATION WITH HIGHER AMERICAN JOINT COMMITTEE ON CANCER STAGES. CONCLUSIONS: THE ABERRANTLY METHYLATED NPTX2 GENE MAY HELP TO DISTINGUISH BETWEEN CHRONIC PANCREATITIS AND PANCREATIC CANCER WITH CONVENTIONAL DIAGNOSTIC TOOLS AND COULD BECOME A VALUABLE DIAGNOSTIC MARKER. 2012 15 3413 35 HSA-MIR-29C AND HSA-MIR-135B DIFFERENTIAL EXPRESSION AS POTENTIAL BIOMARKER OF GASTRIC CARCINOGENESIS. AIM: TO INVESTIGATE THE EXPRESSION PROFILES OF HSA-MIR-29C AND HSA-MIR-135B IN GASTRIC MUCOSAL SAMPLES AND THEIR VALUES AS GASTRIC CARCINOGENESIS BIOMARKERS. METHODS: THE EXPRESSION LEVELS OF HSA-MIR-29C AND HSA-MIR-135B IN NORMAL GASTRIC MUCOSA, NON-ATROPHIC CHRONIC GASTRITIS, INTESTINAL METAPLASIA AND INTESTINAL-TYPE GASTRIC ADENOCARCINOMA WERE ANALYSED USING QUANTITATIVE REAL-TIME PCR. THE DIFFERENCE BETWEEN HSA-MIR-29C AND HSA-MIR-135B EXPRESSION PROFILES IN THE GROUPED SAMPLES WAS EVALUATED BY ANOVA AND STUDENT'S T-TEST TESTS. THE RESULTS WERE ADJUSTED FOR MULTIPLE TESTING BY USING BONFERRONI'S CORRECTION. P VALUES OR =0.5) AMONG FLAT DYSPLASIAS (50%) AND POLYPOID ADENOMAS (51%) UNASSOCIATED WITH CARCINOMA, DYSPLASIAS/ADENOMAS ASSOCIATED WITH ADENOCARCINOMA (47%), AND ADENOCARCINOMA (47%). CIM-H WAS PRESENT IN 15% OF IM, BUT NOT IN NORMAL/CG MUCOSA. THERE WAS A SIGNIFICANT CORRELATION BETWEEN METHYLATION OF HMLH1 AND HIGH-LEVEL OF MICROSATELLITE INSTABILITY (MSI-H): METHYLATION OF HMLH1 WAS PRESENT IN 71% OF MSI-H TUMORS, BUT ONLY 8% OF MSI-LOW TUMORS AND 13% OF MICROSATELLITE-STABLE TUMORS (P=0.0001). THERE WAS NO STATISTICAL DIFFERENCE BETWEEN METHYLATION INDEX AND APC MUTATION. OUR RESULTS INDICATE THAT CONCURRENT PROMOTER METHYLATION IS AN EARLY AND FREQUENT EVENT IN GASTRIC TUMORIGENESIS, INCLUDING BOTH MSI-H AND MICROSATELLITE-STABLE NEOPLASMS. METHYLATION OF THE P16 GENE MAY CONTRIBUTE TO THE MALIGNANT TRANSFORMATION OF GASTRIC PRECURSOR LESIONS. 2004 17 6770 34 [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 18 2439 40 EPIGENETIC SILENCING OF THE MLH1 PROMOTER IN RELATION TO THE DEVELOPMENT OF GASTRIC CANCER AND ITS USE AS A BIOMARKER FOR PATIENTS WITH MICROSATELLITE INSTABILITY: A SYSTEMATIC ANALYSIS. BACKGROUND/AIMS: HUMAN MUTL HOMOLOG 1 (MLH1) PROMOTER METHYLATION WAS REPORTED IN GASTRIC CANCER (GC). THIS STUDY DETERMINED THE CLINICOPATHOLOGICAL, PROGNOSTIC, AND DIAGNOSTIC EFFECTS OF MLH1 PROMOTER METHYLATION IN GC. METHODS: THE COMBINED ODDS RATIO (OR) OR HAZARD RATIO (HR) AND THEIR CORRESPONDING 95% CONFIDENCE INTERVALS (95% CI) WERE CALCULATED. THE POOLED SENSITIVITY, SPECIFICITY, AND AREA UNDER THE CURVE (AUC) WERE ANALYZED. RESULTS: A TOTAL OF 4654 GC PATIENTS AND 3669 NON-MALIGNANT CONTROLS WERE IDENTIFIED IN THIS SYSTEMATIC ANALYSIS. MLH1 PROMOTER METHYLATION WAS SIGNIFICANTLY HIGHER IN GC SAMPLES THAN IN GASTRIC ADENOMAS, CHRONIC GASTRITIS, ADJACENT TISSUES, NORMAL GASTRIC MUCOSA, AND NORMAL HEALTHY BLOOD SAMPLES, BUT IT EXHIBITED A SIMILAR FREQUENCY IN GC VS. INTESTINAL METAPLASIA AND DYSPLASIA SAMPLES. MLH1 PROMOTER METHYLATION CORRELATED WITH AGE AND MICROSATELLITE INSTABILITY (MSI), BUT IT WAS NOT ASSOCIATED WITH GENDER, H. PYLORI INFECTION, SMOKING, DRINKING BEHAVIORS, PATHOLOGICAL HISTOLOGY, TUMOR DIFFERENTIATION, CLINICAL STAGE, LYMPH NODE STATUS, DISTANT METASTASIS, OR OVERALL SURVIVAL OF GC. MLH1 PROMOTER METHYLATION EXHIBITED A POOR SENSITIVITY VALUE (< 0.5) IN PATIENTS WITH GC COMPARED WITH ADJACENT TISSUES, GASTRIC ADENOMAS, CHRONIC GASTRITIS, NORMAL GASTRIC MUCOSA, AND NORMAL HEALTHY BLOOD SAMPLES. THE POOLED SENSITIVITY, SPECIFICITY, AND AUC OF MLH1 PROMOTER METHYLATION IN GC WITH MSI VS. GC WITH MICROSATELLITE STABILITY (MSS) SAMPLES WERE 0.64, 0.96, AND 0.90, RESPECTIVELY. CONCLUSIONS: OUR RESULTS SUGGEST THAT THE DETECTION OF MLH1 PROMOTER METHYLATION MAY BE A POTENTIAL PROGNOSTIC BIOMARKER FOR GC PATIENTS WITH MSI. 2018 19 5116 29 POSITIVE REGULATION OF HUMAN TELOMERASE REVERSE TRANSCRIPTASE GENE EXPRESSION AND TELOMERASE ACTIVITY BY DNA METHYLATION IN PANCREATIC CANCER. AIM: WE SOUGHT TO DETERMINE THE ROLE OF TELOMERASE AND ITS CATALYTIC SUBUNIT HTERT IN PANCREATIC CANCER AND EVALUATE THE EPIGENETIC REGULATION OF HTERT BY PROMOTER METHYLATION. METHODS: THIRTY PAIRED SAMPLES OF PANCREATIC DUCTAL ADENOCARCINOMAS AND ADJACENT NORMAL TISSUE AND 12 CHRONIC PANCREATITIS SAMPLES WERE STUDIED. REVERSE TRANSCRIPTASE POLYMERASE CHAIN REACTION, TELOMERIC REPEAT AMPLIFICATION PROTOCOL ASSAY, AND METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION WERE PERFORMED TO ANALYZE HTERT EXPRESSION, TELOMERASE ACTIVITY, AND METHYLATION STATUS OF GENE PROMOTERS, RESPECTIVELY. RESULT: HTERT AND TELOMERASE ACTIVITY WERE UPREGULATED IN PANCREATIC CANCER COMPARED WITH PAIRED NORMAL TISSUES AND SAMPLES OF PANCREATITIS. HTERT EXPRESSION CORRELATED WITH TELOMERASE ACTIVITY (P \ .05) AND IN TURN CORRELATED POSITIVELY WITH HTERT PROMOTER METHYLATION (P \ .001) AND P16 PROMOTER METHYLATION. HTERT TRANSCRIPT EXPRESSION AND TELOMERASE ACTIVITY BOTH CONFERRED A WORSE OUTCOME BY UNIVARIATE AND MULTIVARIATE ANALYSIS (P \ .05). CONCLUSION: HTERT EXPRESSION AND TELOMERASE ACTIVITY ARE PREDICTORS OF POOR OUTCOME IN PANCREATIC CANCER. HTERT GENE EXPRESSION IS POSITIVELY REGULATED BY PROMOTER METHYLATION. 2009 20 159 32 ABERRANT PROMOTER HYPERMETHYLATION OF MULTIPLE GENES IN GALLBLADDER CARCINOMA AND CHRONIC CHOLECYSTITIS. PURPOSE: ABERRANT METHYLATION OF 5' GENE PROMOTER REGIONS IS AN EPIGENETIC PHENOMENON THAT IS A MAJOR MECHANISM FOR SILENCING OF TUMOR SUPPRESSOR GENES IN MANY CANCER TYPES. THERE IS LIMITED INFORMATION ABOUT THE MOLECULAR CHANGES INVOLVED IN THE PATHOGENESIS OF GALLBLADDER CARCINOMA (GBC), INCLUDING METHYLATION STATUS. EXPERIMENTAL DESIGN: WE INVESTIGATED THE ABERRANT PROMOTER METHYLATION PROFILE OF 24 KNOWN OR SUSPECTED TUMOR SUPPRESSOR GENES IN 50 GBCS AND COMPARED THOSE RESULTS WITH THE FINDINGS IN 25 CHRONIC CHOLECYSTITIS (CC) SPECIMENS WITHOUT CANCER. THE METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION AND COMBINED RESTRICTION ANALYSIS METHODS WERE USED TO DETECT METHYLATION, AND THE RESULTS WERE CONFIRMED BY SEQUENCING OF CLONED POLYMERASE CHAIN REACTION PRODUCTS. RESULTS: IN GBC, GENE METHYLATION FREQUENCIES VARIED FROM 0% TO 80%. TEN GENES DEMONSTRATED RELATIVELY HIGH FREQUENCIES OF ABERRANT METHYLATION: SHP1 (80%), 3-OST-2 (72%), CDH13 (44%), P15INK4B (44%), CDH1 (38%), RUNX3 (32%), APC (30%), RIZ1 (26%), P16INK4A (24%), AND HPP1 (20%). EIGHT GENES (P73, RARBETA2, SOCS-1, DAPK, DCR2, DCR1, HIN1, AND CHFR) SHOWED LOW FREQUENCIES (2-14%) OF METHYLATION, AND NO METHYLATION OF THE REMAINING SIX GENES (TIMP-3, P57, RASSF1A, CRBP1, SYK, AND NORE1) WAS DETECTED. IN CC, METHYLATION WAS DETECTED FOR SEVEN GENES: SHP1 (88%), P15INK4B (28%), 3-OST-2 (12%), CDH1 (12%), CDH13 (8%), DCR2 (4%), AND P16INK4A (4%). SIGNIFICANTLY HIGHER FREQUENCIES OF METHYLATION IN GBC COMPARED WITH CC WERE DETECTED FOR EIGHT GENES (3-OST-2, CDH13, CDH1, RUNX3, APC, RIZ1, P16INK4A, AND HPP1). OF THOSE, FOUR GENES SHOWED FREQUENT METHYLATION (>30%) IN GBCS. THE MEAN METHYLATION INDEX, AN EXPRESSION OF THE AMOUNT OF METHYLATED GENES BY CASE, WAS SIGNIFICANTLY HIGHER IN GBC (0.196 +/- 0.013) COMPARED WITH CC (0.065 +/- 0.008; P < 0.001). CONCLUSIONS: OUR STUDY CONSTITUTES THE MOST COMPREHENSIVE METHYLATION PROFILE REPORT AVAILABLE IN GBC AND DEMONSTRATES THAT THIS NEOPLASM HAS A DISTINCT PATTERN OF ABNORMAL GENE METHYLATION. WHEREAS GALLBLADDERS FROM HEALTHY INDIVIDUAL WERE NOT AVAILABLE, OUR FINDING OF METHYLATION IN CC CASES WITHOUT CANCER SUGGESTS THAT THIS PHENOMENON REPRESENTS AN EARLY EVENT IN THE PATHOGENESIS OF GBC. 2004