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swere excluded. Results: 147 patients included in the study, 53.1% were men, 61.9% com-plained on heartburn and 76.2% were treated with proton pump inhibitors (Table). Intestinalmetaplasia was found in 43.5% of the cases. Results were stratified according to intestinalmetaplasia and compared between Group A (patients with IM) and Group B (without IM)- see table. The only significant difference between the groups in univariate and multivariateanalysis was the finding of diaphragmatic hernia, in 68.8% and 43.3% of IM positiveand negative cases, respectively (P=0.002). Conclusion: Patients with irregular Z-line anddiaphragmatic hernia have higher prevalence of intestinal metaplasia.

M1979

Hypermethylation of the AKAP12 Promoter in Human Esophageal CancerZhe Jin, Yulan Cheng, James P. Hamilton, Yuriko Mori, Alexandru Olaru, Tetsuo Ito,Kwisa Kang, Bogdan C. Paun, Stefan David, Jian Yang, Rachana Agarwal, John M.Abraham, Stephen J. Meltzer

Background & Aims: A-Kinase Anchoring Protein 12 (AKAP12; also known as Gravin, andits rodent ortholog src-suppressed C-kinase substrate, SSeCKS), a multivalent anchoringprotein and an important regulator of the beta2-adrenergic receptor complex, controls cellsignaling, cell adhesion, mitogenesis, and differentiation and possesses tumor suppressoractivity. Recently, AKAP12 promoter CpG island hypermethylation was reported in gastricand colorectal cancers. Thus, it is clear AKAP12 hypermethylation is involved in tumorigen-esis in the human digestive tract; however, it is not known whether and at what neoplasticstage this epigenetic alteration contributes to human esophageal tumorigenesis. Methods:AKAP12 promoter hypermethylation was examined using real-time methylation-specific PCR(qMSP) in 259 human esophageal tissues. Real-time RT-PCR and qMSP were also performedon esophageal cancer cell lines before and after treatment with 5-aza-2'-deoxycytidine (5-Aza-dC). Results: AKAP12 hypermethylation showed highly discriminative receiver-operatorcharacteristic curve profiles, clearly distinguishing esophageal adenocarcinoma (EAC) fromesophageal squamous cell carcinoma (ESCC) and normal esophagus (N) (p<0.0001). AKAP12normalized methylation values were significantly higher in Barrett's metaplasia (BE), dys-plastic Barrett's (D), and EAC than in N (p<0.0000001). AKAP12 hypermethylation frequencywas zero in N but increased early during neoplastic progression, to 38.9% in BE frompatients with Barrett's alone, 52.5% in D, and 52.2% in EAC. AKAP12 hypermethylationwas significantly higher in normal esophageal epithelium from EAC patients (mean = 0.00082)than in normal esophagus from patients without Barrett's or esophageal cancer (mean =0.00007; p = 0.006). There was a significant correlation between AKAP12 hypermethylationand BE segment length, a known clinical neoplastic progression risk factor. In contrast, onlytwo (7.7%) of 26 ESCCs exhibited AKAP12 hypermethylation. Treatment of BIC and OE33EAC cells with 5-aza-2'-deoxycytidine reduced AKAP12 methylation and increased AKAP12mRNA expression. AKAP12 mRNA levels in EACs with unmethylated AKAP12 (mean =0.1663) were higher than levels in EACs with methylated AKAP12 (mean = 0.0668). Conclu-sions: AKAP12 promoter hypermethylation is a common, tissue-specific event in humanEAC, occurs early during Barrett's-associated esophageal neoplastic progression, and is apotential biomarker for the early detection of EAC.

M1980

Loss of Transgelin in Human Colorectal Cancer and Its Up-Regulation InhibitsColon Carcinogenesis Via Inhibiting COX-2 ExpressionMarie Yeo, Hee Jin Park, Dong-Kyu Kim, Young Mi Na, Sung Won Cho, Kwang Jae Lee

We previously reported loss of transgelin (SM22) in colon carcinogenesis of animal modelusing by proteomic study. However, the specific mechanistic link between down-regulationof this protein and colon carcinogenesis in human has not been integrated into molecularunderstanding. We therefore evaluated expression of transgelin in colon tissues derived from15 normal, 15 adenoma, and 31 adenocarcinoma patients by immunohistochemical staining.Presence of transgelin expression was significantly correlated with histopathological grade(p=0.015), tumor site (p=0.045) and differentiation grade (p=0.015), respectively. Transgelinwas expressed in 13 of 15 (86.6%) normal colon tissues, whereas its expression remarkablyattenuated in adenocarcinoma by 14 of 31 (45.1%). Poorly differentiated tumors showedmore down-expression of transgelin compared to well-differentiated tumors and tumorsraised in colon than rectum showed loss of the protein. To test effect of transgelin ontumorigenicity of colon cancer cells, we established colon cancer cell line stably expressedtransgelin and tested tumorigenicity in SCID mice. The result showed that colon cancer celllines expressed strongly transgelin significantly delayed tumor growth in xenograft modelof SCID mice. Interestingly, exogenous expression of transgelin significantly suppressed theexpression of COX-2 gene in colon cancer cells HT1080 and attenuated COX-2 promoteractivity, examined by luciferase reporter assay. Our results suggest that loss of transgelincould be a candidate for biomarker of colon cancer and up-regulation of this proteinattenuated colon carcinogenesis via inhibiting COX-2 expression.

M1981

Synergistic Effect of Microsomal Prostaglandin E Synthase (MPGES)-1,MPGES-2, and COX-2 Coexpression On Colorectal Cancer Patient PrognosisAtsushi Tatsuguchi, Tsuguhiko Seo, Seiichi Shinji, Masaoki Yonezawa, Ken Wada, KeigoMitsui, Shu Tanaka, Shunji Fujimori, Katya Gudis, Takashi Tajiri, Choitsu Sakamoto

Background: The COX-2/prostaglandin E2 pathway has been linked to colorectal cancer(CRC). Microsomal prostaglandin E synthase (mPGES)-1 functions downstream of COX-2for PGE2 biosynthesis. CRC has been shown to overexpress mPGES-1 and mPGES-2;however, the relationship between their expression and the prognosis of CRC patients hasyet to be determined. Aims: To investigate mPGES-1 and mPGES-2 expression in CRCtissue, and to study the relationship between their expression and clinicopathological factorsand patient prognosis; in particular, to determine the effect of mPGES-1 and mPGES-2coexpression on the prognosis of CRC patients that also express the COX-2 protein. Methods:Ten consecutive biopsy samples from CRC patients were analyzed for mPGES-1 mRNA

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expression by real time PCR; and for mPGES-1, mPGES-2, and cytosolic PGES (cPGES)protein levels by Western blot. Localization of each PGES protein was examined immunohis-tochemically in 155 surgical resections, and correlated to clinicopathological factors andpatient prognosis. Results: mPGES-1 mRNA and protein levels were significantly higher inCRC than in paired normal tissues. mPGES-2 and cPGES proteins were expressed in bothCRC and paired normal tissues. mPGES-1 immunoreactivity localized in cancer cells in 43%of cases. mPGES-2 immunoreactivity localized in the epithelial cells of non-neoplastic mucosaand cancer cells. However, in 36% of cases, mPGES-2 immunoreactivity was significantlymore pronounced in cancer cells than in adjacent epithelium. cPGES immunoreactivity washomogeneous in cancer cells in all cases examined and thus determined to be constitutive.mPGES-1 and mPGES-2 correlated with worse prognosis in stage I-III patients in univariateanalysis, and each retained independent prognostic significance in multivariate analysis.Furthermore, survival rates were significantly worse for COX-2/mPGES-1/mPGES-2 positivepatients than for patients that only expressed the COX-2 protein. Conclusions: Our resultssuggest that mPGES-1 and mPGES-2 coexpression may have a synergistic effect on theprognosis of CRC patients that also express COX-2.

M1982

Identification of Differentially Expressed Alternative mRNA IsoformsAssociated with Chemotherapy Resistance in Colon Cancer Cell LinesMalachi Griffith, Michelle J. Tang, Susanna Chan, Jennifer K. Asano, Adrian Ally, TrevorPugh, Isabella T. Tai, Marco A. Marra

The drug 5-fluorouracil (5-FU) is a commonly used chemotherapy for colorectal cancer(CRC). Response to this drug among CRCs is variable and is thought to be mediated inpart by differences in metabolism. A number of genes such as UMPS/OPRT, DPYD, ECGF1,UPP1, TS and others are known to be involved in the metabolism of 5-FU. Differentialexpression and RNA processing of these genes may contribute to 5-FU resistance andpoor clinical outcome. The OBJECTIVE of this study is to identify differentially expressedalternative mRNA isoforms that are predictive of 5-FU resistance. METHODS: We developedan approach that uses a combination of Affymetrix 'Human Exon 1.0 ST' arrays and customsplicing microarrays capable of measuring the expression of mRNA isoforms with subtledifferences in exon content. We used this approach to profile RNA extracted from the celllines MIP101, HCT116, and RKO as well as 5-FU resistant derivatives of each (MIP/5FU,HCT/5FU, and RKO/5FU). Differentially expressed alternative isoforms were predicted fromthe microarray data and some of these findings have been validated by semi-quantitativeRT-PCR. RESULTS: We identified ~25 mRNA isoforms that were differentially expressedbetween MIP101 and MIP/5FU. Interestingly, we found that two isoforms of the gene UMPSwere reciprocally differentially expressed. In both MIP101 and HCT116 the expression ofthe canonical isoform was reduced in resistant cells while a previously unstudied isoformlacking exon 2 exhibited 23.5 ± 1.0 fold over-expression in MIP/5FU (p=0.00437) and 6.3± 1.4 fold over-expression in HCT/5FU (p=0.00193). Global expression and pathway analysisof all three sensitive/resistant cell line pairs is ongoing. CONCLUSIONS: Our results indicatethat differential expression of specific alternative mRNA isoforms of genes involved in themetabolism of 5-FU may be predictive of drug resistance in CRC.

M1983

Influences of Renin-Angiotensin System-Related Gene Polymorphisms OnGastric Cancer Risks in JapanMitsushige Sugimoto, Takahisa Furuta, Chise Kodaira, Masafumi Nishino, MihokoYamade, Mutsuhiro Ikuma, Akira Hishida

Backgrounds and aims: The renin-angiotensin (RA) system plays an important role inhomeostasis. Recently, there is increasing evidences that angiotensin II, which is generatedby chymase and angiotensin-I converting enzyme (ACE), is involved in the regulation ofcell proliferation, angiogenesis, inflammation and tissue remodeling, and therefore, the RAsystem might be related to cancer biology. In gastric carcinogenesis, the relationships amongRA system-gene polymorphisms, histological types and clinical stage are unclear. To deter-mine the possible role of the RA system in the development of gastric cancer and pepticulcer in humans, we examined whether genetic polymorphisms in AGT, CMA/B and ACEwere associated with gastric cancer and peptic ulcer risks in Japanese patients with H. pyloriinfection. Methods: We assessed the AGT-20 A/C, CMA/B A/G and ACE insertion/deletion(I/D) polymorphisms polymorphism in H. pylori-positive patients with gastric cancer (n =135), gastric ulcer (n = 148), and duodenal ulcer (n = 113) and controls (n = 292) consistingof H. pylori-positive gastritis alone (n = 160) and H. pylori-negative subjects (n = 132) byPCR methods. Results: In CMA/B polymorphism, the age and sex-adjusted odds ratios (ORs)of A/A and A/G genotypes relative to G/G genotype for gastric cancer risk were 7.115(95%CI: 1.818 - 27.845) and 1.956 (95%CI: 1137 - 3.366), respectively. The AGT-20 Callele carriage also increased the gastric cancer risk (OR: 1.685, 95%CI: 1.037 - 2.736),especially the intestinal type of gastric cancer (OR: 1.792, 95%CI: 1.040 - 3.089). However,there was no association between ACE polymorphism and susceptibility to gastric cancer.In allele combination analysis of CMA/B and AGT polymorphisms, the A/C allele combina-tions (CMA/B A allale carrier and AGT-20 C allele carrier) significantly increased the riskof gastric cancer development (OR: 4.70, 2.12 - 10.33) compared with the G/I allelecombinations (CMA/B G/G and AGT-20 A/A genotype). Conclusions: The CMA/B and AGT-20 polymorphism was associated with an increased risk for gastric cancer development. Thegenotyping test of renin-angiotensin system could be useful for the screening of individualswith higher risks of gastric cancer. Individuals with the higher gastric cancer risk based onthis genotyping test appear of good indication for chemoprevention with chymase inhibitorand AT1R antagonist or eradication of H. pylori.