Microarray and bioinformatics analyses discriminate among biologic subtypes of esophageal neoplasia

this warrants further study to assessany possible clinical role in identifying high-risk patients in surveillance programmes.

Cyclooxyganase-2 (COX-2) Expression Increases With The Transition From Barrett's Oesophagus Through To High Grade Dysplasia Only: Implications For Chemoprevention Edward Cheong, Institute of Food Research,Norwich United Kingdom; Laszlo Igali, Margaret Mole, Michael Rhodes, Norfolk and Norwich NHS Trust, Norwich United Kingdom; lan T. Johnson, ElizabethLund, Institute of Food Research,Norwich United Kingdom

2267 Microurray And Bioinformatics Analyses Discriminate Among Biologic Subtypes Of Esophageal Neeplasia. Florin M. Selaru, Yan Xu, Univ of Maryland Sch of Medicine, Baltimore, MD; Jing Yin, Valentina Shustova,Tong Zou, CharlesTwigg, John M. Abraham, Yudko Mod, Fumiaki Sato, Ion Cotarla, Univ of Maryland, Baltimore, MD; Bruce D. Greenwald, StephenJ. Meitzer, Univ of Maryland Sch of Medicine, Baltimore, MD cDNA microarrays are powerful tools for monitoring gene expressionto define global genetic scenarios underlying specific disease states. This method organizes complex genomic data into meaningful architecturesthat would otherwise remainundetectableand incomprehensible. Glass microscope slides were printed with 8,000 nonredundantclonesfrom the IMAGEcDNA library. Total RNAwas preparedfrom esophagealtissues, labeled,and hybridizedto the slides, which were scannedand the information gatheredfed into the Stanford bioinformatics program Clustar/Treeview. 16 esophagealsamples were analyzed.Without previous data on histology, using only gene expression profiles, Cluster grouped the samples into 2 main categories.As shown in the clustargram, the first cluster contained 7 out of the 8 cancers (CA) while the other contained all the Barrett's esophagus, plus a CA. Furthermore, in the "CA" group 3 classes were identified: group 1 with 2 squamous cell CAs, group 2 having a signet-ring adenocarcinoma(ADCA),and group 3 containing 3 ADCAsand a CA of unidentified histology. One BA clustered within the BA group, although it was recoveredfrom a patient operated on for CA. The pathological report from this patient, who was previously treated with radio- and chemotherapy,revealedonly BAand no residualCA. Thesedatasuggestthat cDNAmicroarrays, combined with bioinformatics, havethe power to discriminate esophagealCA from premalignant BA. Moreover, microarray analysescan distinguish among various subtypes of cancer. Finally, microarrays show the potential to discover novel pathophysiologicsubtypesthat may eventually supplant traditional histopathologic classifications.

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Background: The incidence of adenocarcinomain Barrett's oesophagus (BO) has increased by eight fold in the past three decades. It is the most rapidly increasing cancer in the western society. Epidemiologicalstudies have shown that intake of aspirin was associatedwith up to 90% decreasedrisk of developingoesophagealcancer.This antitumour effect may be the result of the inhibition of COX-2. Overexpressionof COX-2 plays an important role in gastrointestinal carcinogenesis. HenceselectiveCOX-2 inhibitor could potentially serve as a chemopreventive agent. Objectives: The aim of our study was to elucidate the evolution of COX-2 during the transition of BO to oesophageal adenocarcinoma (OAC) and explore the potential of chemopreventionwith selective COX-2 inhibitors. Methods: 20 paraffin embeddedoesophagogastrectomyand oesophagealbiopsy specimenswere analysedfor COX-2 by immunohistochemistry. Eachspecimen included both BO and high grade dysptasia(HGD) adjacentto the OAC. Semiquantitativeanalysis was performed using UTHSCSAImage Tool version 2.00. We also examinedthe selective inhibition of COX-2 by niflumic acid, nimesulide and NS-398 in a poody differentiated human OAC cell line (0E33) that had arisen from BO. The cell line was analysed for COX-2 expression using Western blotting and cell proliferation assays were performed. Results: Immunohistochemistry revealedan up-regulation of COX-2 in BO,HGD and OAC in 18 out of 20 patients(90%). The level of COX-2 expression displayed were HGD>OAC>BO in decreasingorder. A subset of OACthat was predominantlymucin secreting expressed the highest level of COX-2; this was significantly higher than the HGD. Several OAC showed a heterogeneouspattern of COX-2 expressionfrom cell to cell even within the came gland. The administration of the selectiveCOX-2 inhibitors suppressedthe growth rate of the COX-2 positive OE33 cell line that was dose and time dependent. Conclusions: COX2 expression in Barrett's adenocarcinoma is linked to mucin secreting ability of the cells. COX-2expressionis significantly up-regulatedwhen BO progressesto HGD;it is subsequently down-regulated when cellular differentiation is lost and adenocarcinomadevelops. Henceto achieve the most significant impact from a selective COX-2 inhibitor as a chemopreventive agent, it has to be instituted prior to the IDeSof cellular differentiation when the loss of COX2 occurs.

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Low Frequency Of Colonic Dysplaeias In Patients With Longstanding IBD-Colitie Thomas Ochsenkuehn, CorneliaTillack, Dept of Medicine II, Univ of Munich, Munich Germany; Herbert Stepp, Laser Research Institute, Univ of Munich, Munich Germany; Stephan J. Ott, Dept of Medicine II, Univ of Munich, Munich Germany; Reinhold Baumgartner, Laser Reseamh Institute, Univ of Munich, Munich Germany; Burkhard Goeke, Michael Sackmann, Dept of Medicine II, Univ of Munich, Munich Germany

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2268 Bcl-2, bax and bcl-X Expression in Normal Mucosa, Barrett's Mucoea and Adenocarcinoma el the Esophagus Denis A. Evoy, St James's Hosp, Dublin Ireland; All A. Raouf, Univ of Dublin-Trinity Coil, Dublin Ireland; EleanorCarton, EadhbhardD. Mulligan, Mairead M. Griffin, St James's Hosp, Dublin Ireland; Eamon C. Sweeney,John V. Reynolds, Univ of Dublin-Trinity Coil, Dublin Ireland Background: Bcl-2, bax and bcI-X are a member of family of genes that function as regulator of apoptosis. The susceptibility of cells to apoptotic stimuli may be controlled by the relative ratios of these proteins. Aims: To identify changesin expressionalone the neoplasticpathway. We investigated bcl-2, bax and bcI-X expression in normal esophageal mucosa, Barrett's mucoca and adenocarcinoma of the esophagus. Materials and methods: We studied 109 patients (89 male, 20 female) with primary esophagealadenocarcinoma.Sixty-one patients underwent surgery alone (SA), 48 patients received preoperativechemoradiotherapy(CRX). Bcl-2, bax and bcI-X protein expression were detected by Standard avidin-biotin peroxidase method. Results: Bcl-2, bax and bcI-X expression were detected in the bacal-cell layer of normal squamous epithelium. There was no significant difference in the expression rate of the above mention genes in normal esophagealmucosa. Barrett'S mucoca was identified in 30 of 61 patients of the SA group, in 19 patients pre-CRX and 22 at resection post-CRX. Increasing degreeof dysplasiain Barrett's mucosawas significantly associatedwith reduction of bcl-2 expression (p=O.01), while bax and bcI-X did not vary significantly. There was a significant difference in the expressionrate of bcl-2 to bax and bcl-2 to bcI-X in adenocarcinomas (p
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Background and aim: Patientswith long-standing inflammatory bowel disease(IBD) have an increased risk to develop colonic dysplasias. By conventional colonoscopy dysplasias are likely to be missed. In pilot studies endoscopicfluorescence imaging evolved as a promising new technique to differentiate between normal colonic mucoca and dysplasia.We, therefore, used this technique to prospectivly evaluate the occurence of dysplasias in patients with longstanding IBD. Methods: 25 consecutive patients (n=17 with ulcerative colitis, n=4 with Crohn's colitis, n=4 with indeterminatecolitis, mean age 44 years, range 31-73) with longstanding IBD-colitis and being in low activity or remission were screened for colonic dysplasias.To inducetumor-selectiveintracellularsynthesis of red-fluorescentpmtoporphyrin IX, its precursor, 5-aminolevulinic acid, was given orally at a dose of lg 3-4 hours before examination. Patients were examined by both conventional white light colonoscopy and by fluorescence imaging using a blue light source (400-410 nm) and a sensitive camerato detect fluorescence (D-Light/Tricam SL, Storz, Germany). According to WHO recommendations routine biopsiesweretaken every 10 cm from normal appearingmucosaand from macmscopically suspicious areas.In addition, fluorescence-positiveareashad to be biopsied.All examinations were videotaped.Results: The median duration of the IBD was 14 years (range 4 to 30 years). In all patients complete colonoscopy was performed. Fluorescencewas negative in all but one patient. However, in this one patient, histology revealedno dysplastic tissue, thus the rate of false-positive results was only 4%. In none of the biopsies dysplasiaswere detected hietopathologically,thus no false negative results were found. Exceptfor one patient with a skin rash after sun exposure, no adverse effects were observed. Conclusions: Thorough endoscopic examination with a dense net of biopsies, in addition to fluorescence analysis, revealed no dysplasias in the colon of 25 patients with longstanding IBD-colitis. These data show that the rate of colonic dysplasias in patients with long-standing IBD-colitis may be lower than previously reported.

2271 Cancer Risk and Crehn's Disease in a Canadian Population F Y H Lin, F Farrokhyar, E J. Irvine, McMaster Univ, Hamilton Canada Background: Reported estimates of the relative risk (RR) of cancer in patients with Crohn's disease (CD) vary. Aim: To compare the incidence rates for cancers among CD patients with those of the general population (GP). Methods: An electronic search of admissions in four university hospitals in Hamilton, Ontario was performed for the years 1993-f999 using ICD9 codes 555-555.9 to identify cases of CO and 140-206.9 for cancer. All patients hospitalized with both diagnoses were identified and charts were reviewed.The 1997 crude prevalence rate of CD in Ontario was estimatedto be 211.6/105 (Irvine, unpublisheddata). We estimated the number of patients affected by CD to be 682/year based on the 1996 Hamilton population of 322,352. The crude incidencerates of specific cancers in the CD populationwere calculated and compared to Ontario cancer incidence rates (Health Canada,1997). Results: Thirty-four