1 159 174 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 2 5277 56 PROMOTER METHYLATION PROFILE IN PRENEOPLASTIC AND NEOPLASTIC GALLBLADDER LESIONS. GALLBLADDER CARCINOMA (GBC) IS A HIGHLY MALIGNANT NEOPLASM AND REPRESENTS THE LEADING CAUSE OF CANCER DEATH IN CHILEAN WOMEN. IN ORDER TO DETERMINE THE POTENTIAL ROLE OF PROMOTER METHYLATION IN GALLBLADDER CARCINOGENESIS, WE INVESTIGATED THE FREQUENCY OF THIS EPIGENETIC MECHANISM BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (MSP) IN 35 CHRONIC CHOLECYSTITIS (CC, SEPARATED ACCORDING TO THE PRESENCE OR ABSENCE OF METAPLASIA), 19 EARLY CANCERS (MUCOSA OR MUSCULARIS PROPIA INVASION) AND 48 ADVANCED CARCINOMAS WITH INVASION OF THE GALLBLADDER SUBSEROSA (25 CASES) AND SEROSA (23 CASES). WE EXAMINED 14 GENES AND OBSERVED AN INCREASE OF MULTIGENIC METHYLATION DURING TUMORAL PROGRESSION WHICH WAS NOT SIGNIFICANTLY ASSOCIATED WITH THE PATIENT'S AGE. FOUR GENES (DAPK1, DLC1, TIMP3, AND RARBETA2) DISPLAYED A PROGRESSIVE INCREASE IN THEIR METHYLATION STATUS FROM CC WITHOUT METAPLASIA TO ADVANCED CARCINOMA INVADING THE SEROSA LAYER (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 18 3413 39 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