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BackgroundAccumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population.MethodsThe effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer.ResultsThe effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period.ConclusionsProphylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

The increasing resistance of bacteria to antibiotics has obliged the EU Member States to reduce by 50% the use of antibiotics in animal production by 2030. This study was undertaken with the aim to analyse the use of antibiotics in flocks of broiler turkeys reared in the Warmia and Mazury province in a two-year period.

Bladder cancer is the fifth most common malignancy in the UK. Clinically, the most important process in determining prognosis is the development of invasion, initially of the lamina propria and then beyond as these transitional cell carcinomas (TCCs) progress from stage pT1 to stages T2+. Cadherins and catenins are the main mediators of cell-cell interactions in epithelial tissues, and loss of membranous E-cadherin immunoreactivity is strongly correlated with high grade, advanced stage and poor prognosis in bladder cancer and other malignancies. However, the role of P-cadherin is yet to be fully elucidated in bladder TCC. The objectives of this study were to establish how the expression of cadherins and catenins determines clinical and in vitro behaviour in bladder TCC. Utilizing immunohistochemistry, immunofluorescence and western blotting, we demonstrated a significant reduction in the expression of E-cadherin and β-catenin as grade and stage of bladder TCC progress, accompanied by a significant increase in P-cadherin expression (all p < 0.05, Pearson's χ2 test). Increased P-cadherin expression was also associated with a significantly worse bladder cancer-specific survival (log rank p = 0.008), with Cox regression showing P-cadherin to be an independent prognostic factor. Utilizing a variety of tissue culture models in a range of functional studies, we demonstrated that P-cadherin mediates defective cell-cell adhesion and enhances anchorage-independent growth. The results provide evidence that increased P-cadherin expression promotes a more malignant and invasive phenotype of bladder cancer, and appears to have a novel role late in the disease. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We discuss a resurgence framework in which both hydrodynamical and transient degrees of freedom of N = 4 SYM plasma are incorporated on an equal footing. In consequence, at late times, all information about initial conditions is encoded in infinitely many exponentially damped modes, controlled by transseries parameters.

Eye tracking technology is often used in road safety research. Eye tracker are used during real and simulated driving to investigate driver’s behaviour. It is also used for assessing influence of new elements, like experimental road signs or road signs from different country, on driver’s behaviour and performance. However it should be noted that, the probability that the signs will be noticed cannot be solely assessed by eye tracking data. Therefore there is a need to complete the results with additional sources of data, eg questionnaire study. In the paper results of research concerning road signs perception carried out with 33 volunteers are presented. Twelve boards with different road situations in the form of photos taken from the driver's perspective were prepared. After the exposure, the volunteer answered questions about the memorized information presented on the road signs.

Background: Over 20 susceptibility single-nucleotide polymorphisms (SNP) have been identified for esophageal adenocarcinoma (EAC) and its precursor, Barrett esophagus (BE), explaining a small portion of heritability., Methods: Using genetic data from 4,323 BE and 4,116 EAC patients aggregated by international consortia including the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON), we conducted a comprehensive transcriptome-wide association study (TWAS) for BE/EAC, leveraging Genotype Tissue Expression (GTEx) gene-expression data from six tissue types of plausible relevance to EAC etiology: mucosa and muscularis from the esophagus, gastroesophageal (GE) junction, stomach, whole blood, and visceral adipose. Two analytical approaches were taken: standard TWAS using the predicted gene expression from local expression quantitative trait loci (eQTL), and set-based SKAT association using selected eQTLs that predict the gene expression., Results: Although the standard approach did not identify significant signals, the eQTL set-based approach identified eight novel associations, three of which were validated in independent external data (eQTL SNP sets for EXOC3, ZNF641, and HSP90AA1)., Conclusions: This study identified novel genetic susceptibility loci for EAC and BE using an eQTL set-based genetic association approach., Impact: This study expanded the pool of genetic susceptibility loci for EAC and BE, suggesting the potential of the eQTL set-based genetic association approach as an alternative method for TWAS analysis., (©2022 American Association for Cancer Research.)

Gastroesophageal reflux disease is an extremely common condition worldwide, with the published prevalence rates varying from 2.5% in China to 51.2% in Greece. Its economic and morbidity burden is vast, and optimizing care for this condition carries huge financial and patient‑related benefits. The disease can be complicated by progression to Barrett esophagus (BE), a precancerous condition that affects approximately 2% of the population and remains undiagnosed in many individuals. The National Institute of Clinical Excellence has produced guidelines on cost‑effective management of gastroesophageal reflux disease in patients in the United Kingdom, and the Benign Barrett's and Cancer Taskforce consensus was the largest international review of evidence known on the management of benign BE complications. This paper is a review of these guidelines with updates on new evidence. Areas for future development involve risk‑stratifying patients to surveillance, chemoprevention agents, and genetic biomarkers to help decide who will be at highest risk of malignant progression. Evidence supports the safety of proton pump inhibitors for symptom control in the medium term (ie, 9 years) and reducing the risk of progression of BE, while surgical options are cost‑effective treatments for certain patients. Barrett esophagus surveillance should be directed towards high‑risk groups, while those at lower risk may benefit from chemoprevention strategies.

Background: Trefoil proteins are believed to have an important role in mucosal protection and repair in the gastrointestinal tract. They are well recognized in Barrett's esophagus and considered a potential biomarker for the condition. Metaplasia occurring in the esophageal remnant after esophagectomy is a human model for the early stages of development of Barrett's esophagus., Aims: To assess expression of trefoil proteins in post-esophagectomy columnar epithelium and to use trefoils as a molecular tool to understand regenerative mucosa in the esophagus., Methods: Patients with columnar metaplasia in the esophageal remnant were recruited from a large esophago-gastric cancer center. Trefoil factor expression was determined using immunohistochemical techniques., Results: Samples were obtained from 37 patients. TFF1 and TFF2 were expressed by all samples in a similar pattern to that described in studies of sporadic Barrett's esophagus. TFF3 was less widely expressed and was significantly associated with time elapsed between surgery and endoscopy. Median time from surgery to endoscopy was 8.1 years for patients with TFF3 expression versus 3.4 years for those without (p = 0.004)., Conclusions: Widespread expression of trefoils in this environment suggests that these proteins have an important role in development of Barrett's metaplasia. TFF3 expression may be absent in the early stages of metaplasia and may represent more established columnar epithelium. Biopsy samples from post-esophagectomy patients provide a valuable resource to study the early stages of Barrett's esophagus.

We undertook two of the largest evidence-based reviews in clinical medicine to assess the rationale for the management of gastroesophageal reflux disease, Barrett esophagus (BE), dysplasia, and early invasive esophageal adenocarcinoma. These reviews involved over 150 world experts in 4 continents, and over 20 000 papers were assessed. Quality assessment of the publications was made using Grading of Recommendations Assessment, Development and Evaluation, and of over 240 questions formulated, we were able to answer 30% with an agreement of at least 80%. We agreed on a unique global definition of BE meaning that the presence both of hiatus hernia endoscopically and of intestinal metaplasia histologically should be noted. In addition, we devised an escalation and deescalation pathway for the management of esophagitis, metaplasia, dysplasia, and adenocarcinoma sequence. Endoscopic resection (ER) is recommended for visible mucosal lesions. Moreover, we endorsed the early use of ablation therapy for persistent dysplasia of any degree. In this regard, ER may be both diagnostic and therapeutic and may be sufficient even in early mucosal lesions (T1m). In conclusion, fewer people should be surveyed but those that do will require more detailed mapping and endoscopic interventions than currently. In addition, patients accumulating other potentially life-threaten-ing comorbidities should be offered cessation of surveillance. In the future, chemoprevention may be the game-changing solution but results from large randomized trials, including AspECT and BOSS, are awaited.

Objective: Barrett's oesophagus shows appearances described as 'intestinal metaplasia', in structures called 'crypts' but do not typically display crypt architecture. Here, we investigate their relationship to gastric glands., Methods: Cell proliferation and migration within Barrett's glands was assessed by Ki67 and iododeoxyuridine (IdU) labelling. Expression of mucin core proteins (MUC), trefoil family factor (TFF) peptides and LGR5 mRNA was determined by immunohistochemistry or by in situ hybridisation, and clonality was elucidated using mitochondrial DNA (mtDNA) mutations combined with mucin histochemistry., Results: Proliferation predominantly occurs in the middle of Barrett's glands, diminishing towards the surface and the base: IdU dynamics demonstrate bidirectional migration, similar to gastric glands. Distribution of MUC5AC, TFF1, MUC6 and TFF2 in Barrett's mirrors pyloric glands and is preserved in Barrett's dysplasia. MUC2-positive goblet cells are localised above the neck in Barrett's glands, and TFF3 is concentrated in the same region. LGR5 mRNA is detected in the middle of Barrett's glands suggesting a stem cell niche in this locale, similar to that in the gastric pylorus, and distinct from gastric intestinal metaplasia. Gastric and intestinal cell lineages within Barrett's glands are clonal, indicating derivation from a single stem cell., Conclusions: Barrett's shows the proliferative and stem cell architecture, and pattern of gene expression of pyloric gastric glands, maintained by stem cells showing gastric and intestinal differentiation: neutral drift may suggest that intestinal differentiation advances with time, a concept critical for the understanding of the origin and development of Barrett's oesophagus., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Dissecting how genetic and environmental influences impact on learning is helpful for maximizing numeracy and literacy. Here we show, using twin and genome-wide analysis, that there is a substantial genetic component to children's ability in reading and mathematics, and estimate that around one half of the observed correlation in these traits is due to shared genetic effects (so-called Generalist Genes). Thus, our results highlight the potential role of the learning environment in contributing to differences in a child's cognitive abilities at age twelve.

Background: Genome-wide association studies (GWAS) have identified several loci associated with schizophrenia and/or bipolar disorder. We performed a GWAS of psychosis as a broad syndrome rather than within specific diagnostic categories., Methods: 1239 cases with schizophrenia, schizoaffective disorder, or psychotic bipolar disorder; 857 of their unaffected relatives, and 2739 healthy controls were genotyped with the Affymetrix 6.0 single nucleotide polymorphism (SNP) array. Analyses of 695,193 SNPs were conducted using UNPHASED, which combines information across families and unrelated individuals. We attempted to replicate signals found in 23 genomic regions using existing data on nonoverlapping samples from the Psychiatric GWAS Consortium and Schizophrenia-GENE-plus cohorts (10,352 schizophrenia patients and 24,474 controls)., Results: No individual SNP showed compelling evidence for association with psychosis in our data. However, we observed a trend for association with same risk alleles at loci previously associated with schizophrenia (one-sided p = .003). A polygenic score analysis found that the Psychiatric GWAS Consortium's panel of SNPs associated with schizophrenia significantly predicted disease status in our sample (p = 5 × 10(-14)) and explained approximately 2% of the phenotypic variance., Conclusions: Although narrowly defined phenotypes have their advantages, we believe new loci may also be discovered through meta-analysis across broad phenotypes. The novel statistical methodology we introduced to model effect size heterogeneity between studies should help future GWAS that combine association evidence from related phenotypes. Applying these approaches, we highlight three loci that warrant further investigation. We found that SNPs conveying risk for schizophrenia are also predictive of disease status in our data., (Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

These guidelines provide a practical and evidence-based resource for the management of patients with Barrett's oesophagus and related early neoplasia. The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument was followed to provide a methodological strategy for the guideline development. A systematic review of the literature was performed for English language articles published up until December 2012 in order to address controversial issues in Barrett's oesophagus including definition, screening and diagnosis, surveillance, pathological grading for dysplasia, management of dysplasia, and early cancer including training requirements. The rigour and quality of the studies was evaluated using the SIGN checklist system. Recommendations on each topic were scored by each author using a five-tier system (A+, strong agreement, to D+, strongly disagree). Statements that failed to reach substantial agreement among authors, defined as >80% agreement (A or A+), were revisited and modified until substantial agreement (>80%) was reached. In formulating these guidelines, we took into consideration benefits and risks for the population and national health system, as well as patient perspectives. For the first time, we have suggested stratification of patients according to their estimated cancer risk based on clinical and histopathological criteria. In order to improve communication between clinicians, we recommend the use of minimum datasets for reporting endoscopic and pathological findings. We advocate endoscopic therapy for high-grade dysplasia and early cancer, which should be performed in high-volume centres. We hope that these guidelines will standardise and improve management for patients with Barrett's oesophagus and related neoplasia.

Background & Aims: The existence of slowly cycling, adult stem cells has been challenged by the identification of actively cycling cells. We investigated the existence of uncommitted, slowly cycling cells by tracking 5-iodo-2'-deoxyuridine (IdU) label-retaining cells (LRCs) in normal esophagus, Barrett's esophagus (BE), esophageal dysplasia, adenocarcinoma, and healthy stomach tissues from patients., Methods: Four patients (3 undergoing esophagectomy, 1 undergoing esophageal endoscopic mucosal resection for dysplasia and an esophagectomy for esophageal adenocarcinoma) received intravenous infusion of IdU (200 mg/m(2) body surface area; maximum dose, 400 mg) over a 30-minute period; the IdU had a circulation half-life of 8 hours. Tissues were collected at 7, 11, 29, and 67 days after infusion, from regions of healthy esophagus, BE, dysplasia, adenocarcinoma, and healthy stomach; they were analyzed by in situ hybridization, flow cytometry, and immunohistochemical analyses., Results: No LRCs were found in dysplasias or adenocarcinomas, but there were significant numbers of LRCs in the base of glands from BE tissue, in the papillae of the basal layer of the esophageal squamous epithelium, and in the neck/isthmus region of healthy stomach. These cells cycled slowly because IdU was retained for at least 67 days and co-labeling with Ki-67 was infrequent. In glands from BE tissues, most cells did not express defensin-5, Muc-2, or chromogranin A, indicating that they were not lineage committed. Some cells labeled for endocrine markers and IdU at 67 days; these cells represented a small population (<0.1%) of epithelial cells at this time point. The epithelial turnover time of the healthy esophageal mucosa was approximately 11 days (twice that of the intestine)., Conclusions: LRCs of human esophagus and stomach have many features of stem cells (long lived, slow cycling, uncommitted, and multipotent), and can be found in a recognized stem cell niche. Further analyses of these cells, in healthy and metaplastic epithelia, is required., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Little is known about the stem cell organisation of the normal oesophagus or Barrett's metaplastic oesophagus. Using non-pathogenic mitochondrial DNA mutations as clonal markers, the authors reveal the stem cell organisation of the human squamous oesophagus and of Barrett's metaplasia and determine the mechanism of clonal expansion of mutations., Methods: Mutated cells were identified using enzyme histochemistry to detect activity of cytochrome c oxidase (CCO). CCO-deficient cells were laser-captured and mutations confirmed by PCR sequencing. Cell lineages were identified using immunohistochemistry., Results: The normal squamous oesophagus contained CCO-deficient patches varying in size from around 30 μm up to about 1 mm. These patches were clonal as each area within a CCO-deficient patch contained an identical mitochondrial DNA mutation. In Barrett's metaplasia partially CCO-deficient glands indicate that glands are maintained by multiple stem cells. Wholly mutated Barrett's metaplasia glands containing all the expected differentiated cell lineages were seen, demonstrating multilineage differentiation from a clonal population of Barrett's metaplasia stem cells. Patches of clonally mutated Barrett's metaplasia glands were observed, indicating glands can divide to form patches. In one patient, both the regenerating squamous epithelium and the underlying glandular tissue shared a clonal mutation, indicating that they are derived from a common progenitor cell., Conclusion: In normal oesophageal squamous epithelium, a single stem cell clone can populate large areas of epithelium. Barrett's metaplasia glands are clonal units, contain multiple multipotential stem cells and most likely divide by fission. Furthermore, a single cell of origin can give rise to both squamous and glandular epithelium suggesting oesophageal plasticity.

Barrett's esophagus is an increasingly common disease that is strongly associated with reflux of stomach acid and usually a hiatus hernia, and it strongly predisposes to esophageal adenocarcinoma (EAC), a tumor with a very poor prognosis. We report the first genome-wide association study on Barrett's esophagus, comprising 1,852 UK cases and 5,172 UK controls in the discovery stage and 5,986 cases and 12,825 controls in the replication stage. Variants at two loci were associated with disease risk: chromosome 6p21, rs9257809 (Pcombined=4.09×10(-9); odds ratio (OR)=1.21, 95% confidence interval (CI)=1.13-1.28), within the major histocompatibility complex locus, and chromosome 16q24, rs9936833 (Pcombined=2.74×10(-10); OR=1.14, 95% CI=1.10-1.19), for which the closest protein-coding gene is FOXF1, which is implicated in esophageal development and structure. We found evidence that many common variants of small effect contribute to genetic susceptibility to Barrett's esophagus and that SNP alleles predisposing to obesity also increase risk for Barrett's esophagus.

Background & Aims: Esophageal adenocarcinoma (EA) is increasingly common among patients with Barrett's esophagus (BE). We aimed to provide consensus recommendations based on the medical literature that clinicians could use to manage patients with BE and low-grade dysplasia, high-grade dysplasia (HGD), or early-stage EA., Methods: We performed an international, multidisciplinary, systematic, evidence-based review of different management strategies for patients with BE and dysplasia or early-stage EA. We used a Delphi process to develop consensus statements. The results of literature searches were screened using a unique, interactive, Web-based data-sifting platform; we used 11,904 papers to inform the choice of statements selected. An a priori threshold of 80% agreement was used to establish consensus for each statement., Results: Eighty-one of the 91 statements achieved consensus despite generally low quality of evidence, including 8 clinical statements: (1) specimens from endoscopic resection are better than biopsies for staging lesions, (2) it is important to carefully map the size of the dysplastic areas, (3) patients that receive ablative or surgical therapy require endoscopic follow-up, (4) high-resolution endoscopy is necessary for accurate diagnosis, (5) endoscopic therapy for HGD is preferred to surveillance, (6) endoscopic therapy for HGD is preferred to surgery, (7) the combination of endoscopic resection and radiofrequency ablation is the most effective therapy, and (8) after endoscopic removal of lesions from patients with HGD, all areas of BE should be ablated., Conclusions: We developed a data-sifting platform and used the Delphi process to create evidence-based consensus statements for the management of patients with BE and early-stage EA. This approach identified important clinical features of the diseases and areas for future studies., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Despite modern advances in cancer research, screening and treatment options, gastrointestinal tumours remain a leading cause of death worldwide. Both oesophageal and colorectal malignancies carry high rates of morbidity and mortality, presenting a challenge to clinicians in search of effective management strategies. In recent years, the increasing burden of disease has led to a paradigm shift in our approach from treatment to prevention. Among several agents postulated as having a chemopreventive effect on the gastrointestinal tract, aspirin has been most widely studied and has gained universal acknowledgement. There is an expanding evidence base for aspirin as a key mediator in the prevention of dysplastic change in Barrett's oesophagus and colorectal adenomas. Its cardioprotective effects also impact positively on the patient population in question, many of whom have ischaemic vascular disease. The major side effects of aspirin have been well-characterised and may cause significant morbidity and mortality in their own right. Complications such as peptic ulceration, upper gastrointestinal bleeding and haemorrhagic stroke pose serious threats to the routine administration of aspirin and hence a balance between the risks and benefits must be struck if chemoprevention is to be effective on a large scale. In this review, we address the current evidence base for aspirin use in gastrointestinal oncology, as well as several key questions surrounding its safety, cost effectiveness and optimal dose., (Copyright © 2012. Published by Elsevier Ltd.)

Recent decades have seen a worrying trend in incidence rates of distal oesophageal and proximal gastric cancers. Fuelled by radical changes in lifestyle, diet, physical activity and environmental exposures, as well as an ageing population and host genetic predisposition, the incidence of oesophageal adenocarcinoma (OAC) is on the rise in Western populations. While overall incidence of gastric cancers is declining, the ageing of society means that an increase in absolute numbers is expected over coming years. Both cancers tend to present at an advanced stage, hence prognosis remains poor despite increasingly effective screening and treatment strategies. The development of gastric and oesophageal malignancies is influenced by myriad factors, not least geographical, racial and socioeconomic differences in addition to lifestyle choices. The multidimensional nature of these risk factors requires a holistic understanding of their net influence in the development of malignancy. This review explores the evidence base for established and putative risk factors in the development of gastric and oesophageal cancers. It is hoped that with a clear understanding of important risk factors, a multidisciplinary approach including effective primary prevention, regular screening of high-risk groups and continued research into the molecular biology of gastrointestinal carcinogenesis may facilitate a reduction in incidence rates, as well as early detection and optimal management of upper gastrointestinal malignancies.

Background & Aims: Studies of the clonal architecture of gastric glands with intestinal metaplasia are important in our understanding of the progression from metaplasia to dysplasia. It is not clear if dysplasias are derived from intestinal metaplasia or how dysplasias expand. We investigated whether cells within a metaplastic gland share a common origin, whether glands clonally expand by fission, and determine if such metaplastic glands are genetically related to the associated dysplasia. We also examined the clonal architecture of entire dysplastic lesions and the genetic changes associated with progression within dysplasia., Methods: Cytochrome c oxidase-deficient (CCO⁻) metaplastic glands were identified using a dual enzyme histochemical assay. Clonality was assessed by laser capture of multiple cells throughout CCO⁻ glands and polymerase chain reaction sequencing of the entire mitochondrial DNA (mtDNA) genome. Nuclear DNA abnormalities in individual glands were identified by laser capture microdissection polymerase chain reaction sequencing for mutation hot spots and microsatellite loss of heterozygosity analysis., Results: Metaplastic glands were derived from the same clone-all lineages shared a common mtDNA mutation. Mutated glands were found in patches that had developed through gland fission. Metaplastic and dysplastic glands can be genetically related, indicating the clonal origin of dysplasia from metaplasia. Entire dysplastic fields contained a founder mutation from which multiple, distinct subclones developed., Conclusions: There is evidence for a distinct clonal evolution from metaplasia to dysplasia in the human stomach. By field cancerization, a single clone can expand to form an entire dysplastic lesion. Over time, this field appears to become genetically diverse, indicating that gastric cancer can arise from a subclone of the founder mutation., (Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Esophageal adenocarcinoma is increasing in incidence. The main risk factor is the premalignant condition of Barrett's esophagus. There is great interest in chemoprevention to prevent or slow malignant transformation. There are many agents proposed as playing a role in chemoprevention; however, none is licensed for this role as yet. Aspirin possesses many favorable qualities for chemoprevention and is the focus of the largest randomized control trial in this field., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Together, gastrointestinal (GI) cancers now account for 25% of neoplastic deaths in the West. In Poland, GI cancer rates are likely to increase further as westernization progresses. Given that conventional cancer therapies have made only modest reductions in cancer mortality, there is a great interest in chemoprevention to prevent or slow malignant transformation from premalignant lesions. The financial pressures in the immediate future require even more stringent criteria for chemopreventive agents - they must be cheap but also safe and efficacious. In this regard, several reviews have indicated that aspirin possesses many favorable qualities for chemoprevention. Furthermore, meta-analyses indicate that aspirin may decrease cancer by approximately 30%. Several large clinical trials are underway, including AspECT (Aspirin and Esomeprazole Chemoprevention Trial) that aims not only to prevent cancer but also decrease the gastric side effects by combining aspirin with potent acid-suppressing drugs. In conclusion, whether aspirin will be the world's first proven chemopreventive agent is currently unknown but the evidence looks hopeful.

Aims: beta-Catenin is an important molecule in cancer biology. Membranous beta-catenin enhances cellular differentiation and inhibits invasion by its action on E-cadherin. The aim was to ascertain whether the cellular expression of these molecules in colorectal and oesophageal cancer specimens is associated with survival in patients with gastrointestinal cancer., Methods and Results: Tumour samples from 149 patients undergoing resection for colorectal adenocarcinoma and 147 patients undergoing resection for oesophageal adenocarcinoma were retrospectively analysed using immunohistochemical techniques to assess beta-catenin expression. Increasing beta-catenin expression in the cytoplasm was associated with improved survival for colorectal cancer cases on both univariate (P = 0.003) and multivariate (P = 0.01) analysis. In addition, increased expression in the most recent cohort of oesophageal adenocarcinoma patients was associated with improved TNM staging (P = 0.007). Membrane expression was weakly associated with survival in colorectal cancer on univariate analysis (P = 0.09), but not on multivariate analysis (P = 0.21). Complete absence of beta-catenin expression at all three sites was associated with reduced 5-year survival in colorectal cancer., Conclusions: This is one of the largest prognostic studies of beta-catenin in gastrointestinal adenocarcinoma. It shows that low levels of cytoplasmic beta-catenin expression are associated with reduced survival in patients with colorectal cancer as well as worse TNM staging in oesophageal adenocarcinoma (a recognized surrogate end-point for survival). We believe this is the first time that this has been reported. This finding should be tested prospectively in oncological trials to validate whether the presence of cytoplasmic beta-catenin could be used as a prognostic marker for less aggressive disease.

Background & Aims: According to the somatic mutation theory, monoclonal colorectal lesions arise from sequential mutations in the progeny of a single stem cell. However, studies in a sex chromosome mixoploid mosaic (XO/XY) patient indicated that colorectal adenomas were polyclonal. We assessed adenoma clonality on an individual crypt basis and completed a genetic dependency analysis in carcinomas-in-adenomas to assess mutation order and timing., Methods: Polyp samples were analyzed from the XO/XY individual, patients with familial adenomatous polyposis and attenuated familial adenomatous polyposis, patients with small sporadic adenomas, and patients with sporadic carcinoma-in-adenomas. Clonality was analyzed using X/Y chromosome fluorescence in situ hybridization, analysis of 5q loss of heterozygosity in XO/XY tissue, and sequencing of adenomatous polyposis coli. Individual crypts and different phenotypic areas of carcinoma-in-adenoma lesions were analyzed for mutations in adenomatous polyposis coli, p53, and K-RAS; loss of heterozygosity at 5q, 17p, and 18q; and aneuploidy. Phylogenetic trees were constructed., Results: All familial adenomatous polyposis-associated adenomas and some sporadic lesions had polyclonal genetic defects. Some independent clones appeared to be maintained in advanced adenomas. No clear obligate order of genetic events was established. Top-down growth of dysplastic tissue into neighboring crypts was a possible mechanism of clonal competition., Conclusions: Human colorectal microadenomas are polyclonal and may arise from a combination of host genetic features, mucosal exposures, and active crypt interactions. Analyses of tumor phylogenies show that most lesions undergo intermittent genetic homogenization, but heterotypic mutation patterns indicate that independent clonal evolution can occur throughout adenoma development. Based on observations of clonal ordering the requirement and timing of genetic events during neoplastic progression may be more variable than previously thought., (2010 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Barrett's oesophagus is a common premalignant lesion caused partly by acid reflux. Although the requisite therapy, proton pump inhibitors (PPIs), have been implicated in the progression of Barrett's oesophagus in animal models, harmful effects of prolonged PPI therapy in Barrett's oesophagus is both inconclusive and controversial. We therefore aimed to test the role of PPI-induced hypergastrinaemia in vitro and see whether any biological parameters were useful surrogates of long-term therapy in man., Methods: We undertook detailed serological and tissue assessment of gastrin and CCK(2) receptors in 90 patients randomised to different doses of PPI therapy during a detailed 2-year follow-up. We also undertook a comprehensive study of cell models to study the consequential biological effects of gastrin on the mucosa., Results: Gastrin and its cognate receptor CCK(2)R were expressed highest in the stomach, then less in Barrett's oesophagus and least in squamous oesophagus (SqE) (n=20 paired t-test, p<0.01). Analysis of the change in Barrett's oesophagus segment length change in 70 patients who were randomised to high or low PPI dose showed no difference over 2 years (n=70 t-test, p=0.8). Prolonged PPI use did, however, increase the serum gastrin, (36 pg/ml+/-57 pg/ml to 103 pg/ml+/-94 pg/ml (paired t test, p<0.05)). In vitro gastrin also induced changes in OE33(E)(cckr) Barrett's oesophagus cells, but not OE21(E)(cckr) squamous cells, transfected with CCK(2)R; migration was induced by 1 ng/ml of gastrin but proliferation only increased with 100 ng/ml (paired t-test, p<0.01) and both were abolished by antagonists., Conclusion: While the short-term effects of gastrin enhance epithelial restitution in Barrett's oesophagus (but not squamous mucosa) there is no clinical evidence that Barrett's oesophagus length expands over time. This study, which is the largest and longest term randomised controlled trial of gastrin biology in Barrett's oesophagus, is further proof of the clinical safety of PPI therapy.

Gastrointestinal cancers account for approximately 25% of all cancer deaths in the Western world. There is a need for a preventive strategy that can utilize biomarkers in order to stratify patients into appropriate screening or surveillance programs. Biomarkers are clinical variables associated with clinical outcomes. In cancer biology, the best biomarkers are germline adenomatous polyposis coli mutations, which are highly predictive of colon cancer. In other areas, such as Barrett's esophagus, despite early excellent success in identifying the importance of p16, p53, and aneuploidy in esophageal adenocarcinoma pathogenesis, useful biomarkers are still not widely used in clinical practice. New molecular biomarkers may be identified in the next decade, such as epigenetic methylation patterns and genetic polymorphisms. In the meantime, clinicians must rely on robust, inexpensive methods such as standard histopathology. Dysplasia is still the mainstay of cancer prediction in most inflammatory disorders of the GI tract and is an independent marker of cancer risk.

Little is known about the clonal structure or stem cell architecture of the human small intestinal crypt/villus unit, or how mutations spread and become fixed. Using mitochondrial DNA (mtDNA) mutations as a marker of clonal expansion of stem cell progeny, we aimed to provide answers to these questions. Enzyme histochemistry (for cytochrome c oxidase and succinate dehydrogenase) was performed on frozen sections of normal human duodenum. Laser-capture microdissected cells were taken from crypts/villi. The entire mitochondrial genome was amplified using a nested PCR protocol; sequencing identified mutations and immunohistochemistry demonstrated specific cell lineages. Cytochrome c oxidase-deficient small bowel crypts were observed within all sections: negative crypts contained the same clonal mutation and all differentiated epithelial lineages were present, indicating a common stem cell origin. Mixed crypts were also detected, confirming the existence of multiple stem cells. We observed crypts where Paneth cells were positive but the rest of the crypt was deficient. We have demonstrated patches of deficient crypts that shared a common mutation, suggesting that they have divided by fission. We have shown that all cells within a small intestinal crypt are derived from one common stem cell. Partially-mutated crypts revealed some novel features of Paneth cell biology, suggesting that either they are long-lived or a committed Paneth cell-specific long-lived progenitor was present. We have demonstrated that mutations are fixed in the small bowel by fission and this has important implications for adenoma development.

Background & Aims: The clonality of colitis-associated neoplasia has not been fully determined. One previous report showed polyclonal origins with subsequent monoclonal outgrowth. We aimed to assess the clonality and mutation burden of individual crypts in colitis-associated neoplasias to try to identify gatekeeping founder mutations, and explore the clonality of synchronous lesions to look for field effects., Methods: Individual crypts (range, 8-21 crypts) were microdissected from across 17 lesions from 10 patients. Individual crypt adenomatous polyposis coli (APC), p53, K-RAS, and 17p loss of heterozygosity mutation burden was established using polymerase chain reaction and sequencing analysis. Serial sections underwent immunostaining for p53, beta-catenin, and image cytometry to detect aneuploidy., Results: In most lesions an oncogenic mutation could be identified in all crypts across the lesion showing monoclonality. This founder mutation was a p53 lesion in the majority of neoplasms but 4 tumors had an initiating K-RAS mutation. Some nondysplastic crypts surrounding areas of dysplasia were found to contain clonal p53 mutations and in one case 3 clonal tumors arose from a patch of nondysplastic crypts containing a K-RAS mutation., Conclusions: This study used mutation burden analysis of individual crypts across colitis-associated neoplasms to show lesion monoclonality. This study confirmed p53 mutation as initiating mutation in the majority of lesions, but also identified K-RAS activation as an alternative gatekeeping mutation. Local and segmental field cancerization was found by showing pro-oncogenic mutations in nondysplastic crypts surrounding neoplasms, although field changes are unlikely to involve the entire colon because widely separated tumors were genetically distinct.

Oesophageal cancer is on the rise and often present in an advanced state. Advances in surgical techniques, chemotherapy and radiotherapy have not changed the prognosis of oesophageal cancer over the last 20 years. With the unravelling of molecular biology of carcinogenesis in the oesophagus, there is a need for a paradigm shift from cancer treatment to prevention. Barrett's oesophagus is the commonest pre-malignant condition for development of oesophageal adenocarcinomas and is eminently suitable for the study of chemoprevention strategies. Now in its third year, the AspECT trial is the biggest, multicentre, randomised controlled clinical trial looking at the long-term chemoprevention effect of esomeprazole with or without aspirin. More than 85% of the participants tolerated the medications at the initial intended doses, and the drop-out rate has been 7%; the interim analysis is due in 2011.

P-cadherin is normally expressed in the basal layer of squamous epithelia and absent from the healthy intestine and colon. We have previously shown it to be expressed in all inflamed, hyperplastic, and dysplastic intestinal and colonic mucosa. This study aimed to better understand the mechanisms controlling the expression of P-cadherin and the biological effects of its ectopic presence in the intestine and colon. We investigated the CpG methylation status of the P-cadherin (CDH3) promoter and P-cadherin mRNA and protein expression in cases of familial and sporadic colorectal cancer (CRC). The CDH3 promoter was hypomethylated in colonic aberrant crypt foci, in CRC, and, occasionally, in the normal epithelium adjacent to cancer, demonstrating a potential "field effect" of cancerization. The hypomethylation was also associated with induction of P-cadherin expression in the neoplastic colon (P < 0.0001). We then created transgenic mice that overexpressed P-cadherin specifically in the intestinal and colonic epithelium under the liver fatty acid binding protein promoter. Forced ectopic expression of P-cadherin accompanied by indomethacin-induced inflammation resulted in a 3-fold higher crypt fission rate within the small and large intestines in the homozygous mice compared with the wild-type animals (P < 0.02). We conclude that epigenetic demethylation of the P-cadherin promoter in the human intestine permits its ectopic expression very early in the colorectal adenoma-carcinoma sequence and persists during invasive cancer. Induced P-cadherin expression, especially in mucosal damage, leads to an increased rate of crypt fission, a common feature of clonal expansion in gastrointestinal dysplasia.

Adenocarcinoma related to Barrett's esophagus (BE) is increasing in the West faster than any other cancer. There are many potential chemopreventive agents as well as predictive biomarkers of cancer progression, but what is required is a robust high-throughput model in which to test hypotheses preclinically. The pathophysiology of metaplasia and cancer has been studied in 10 animal species. Though they have considerable genetic divergence, anatomical dissimilarity, and experimental flaws, they have provided some data to test in the clinic, especially relating to activation of common genetic pathways, role of hypergastrinemia, and duodenogastric reflux in cancer progression. In this regard, the human postesophagectomy model, which has a 30% recurrence of BE within 3 yr and a 5% recurrence of adenocarcinoma over 10 yr, is now being utilized to understand how human metaplasia occurs. Furthermore, improved clinical trial designs mean that more sophisticated questions can be addressed in man.

Objectives: Current models of clonal expansion in human Barrett's oesophagus are based upon heterogenous, flow-purified biopsy analysis taken at multiple segment levels. Detection of identical mutation fingerprints from these biopsy samples led to the proposal that a mutated clone with a selective advantage can clonally expand to fill an entire Barrett's segment at the expense of competing clones (selective sweep to fixation model). We aimed to assess clonality at a much higher resolution by microdissecting and genetically analysing individual crypts. The histogenesis of Barrett's metaplasia and neo-squamous islands has never been demonstrated. We investigated the oesophageal gland squamous ducts as the source of both epithelial sub-types., Methods: Individual crypts across Barrett's biopsy and oesophagectomy blocks were dissected. Determination of tumour suppressor gene loss of heterozygosity patterns, p16 and p53 point mutations were carried out on a crypt-by-crypt basis. Cases of contiguous neo-squamous islands and columnar metaplasia with oesophageal squamous ducts were identified. Tissues were isolated by laser capture microdissection and genetically analysed., Results: Individual crypt dissection revealed mutation patterns that were masked in whole biopsy analysis. Dissection across oesophagectomy specimens demonstrated marked clonal heterogeneity, with multiple independent clones present. We identified a p16 point mutation arising in the squamous epithelium of the oesophageal gland duct, which was also present in a contiguous metaplastic crypt, whereas neo-squamous islands arising from squamous ducts were wild-type with respect to surrounding Barrett's dysplasia., Conclusions: By studying clonality at the crypt level we demonstrate that Barrett's heterogeneity arises from multiple independent clones, in contrast to the selective sweep to fixation model of clonal expansion previously described. We suggest that the squamous gland ducts situated throughout the oesophagus are the source of a progenitor cell that may be susceptible to gene mutation resulting in conversion to Barrett's metaplastic epithelium. Additionally, these data suggest that wild-type ducts may be the source of neo-squamous islands.

Objective & Method: A dimeric form of pyruvate kinase isoenzyme (tumour M2-PK) is predominantly found in highly proliferating cells. Sandwich ELISA with monoclonal antibodies against dimeric (tumour) M2-PK was used to measure faecal tumour M2-PK in; 13 controls, 10 patients with colonic polyps and 32 patients with colorectal cancer., Results: Levels of faecal tumour M2-PK were higher in patients with colorectal cancer (median 11.72 U/ml; range 0.9-146.95 U/ml, P = 0.0001) and polyps greater than 10 mm (median 2.54 U/ml; range 0.9-29.46 U/ml, P = 0.041) when compared with controls (median 1.75 U/ml; range 0.9-3.41 U/ml). Furthermore, levels were higher in stages Duke's B (P = 0.013) and Duke's C (P = 0.43) than in Duke's A. Six months postsurgery faecal tumour M2-PK levels fell significantly to 3.46 U/ml (range 1.03-9.05 U/ml, P = 0.001). The sensitivity of a positive faecal tumour M2-PK test, defined as a level above 3.33 U/ml, was 91% for colorectal cancer, 60% for >10 mm and 20% for <10 mm polyps, with a specificity of 92%., Conclusion: Faecal tumour M2-PK is a highly sensitive marker for colorectal cancer and larger polyps. It also correlates with more advanced stages of colorectal cancer and its reduction is associated with successful surgical intervention.

Hereditary diffuse gastric cancer and tylosis are autosomal dominant cancer susceptibility syndromes. Accumulating evidence also suggests a genetic contribution to Barrett's esophagus and adenocarcinoma, traditionally considered acquired disorders. In this article we review the current knowledge on the genetic mechanisms underlying hereditary diffuse gastric cancer, tylosis, and Barrett's esophagus. Hereditary diffuse gastric cancer is a paradigm for hereditary cancer susceptibility syndromes with E-cadherin implicated as the dominant oncogene in up to one-third of cases. Tylosis in contrast remains the paradox as whilst the putative abnormality has been localized to the long arm of chromosome 17, sequencing of this region has failed to reveal a disease causing mutation. In the case of Barrett's esophagus and adenocarcinoma, although a validated specific disease-associated gene is yet to be identified, the increasing body of evidence of a possible genetic link is paving the way for subsequent prognostic studies such as AspECT (Aspirin Esomeprazole Chemoprevention Trial). For the clinician these advances in understanding are already having implications for practice in terms of improved screening and the stratification of management strategies. As the mechanisms continue to be defined, there is the real possibility that these mechanisms could be exploited or subverted in the design of new therapies. In the meantime, however, clinicians should undertake rigorous biopsy programs to ensure early invasive lesions are detected.

Background & Aims: How mutations are established and spread through the human stomach is unclear because the clonal structure of gastric mucosal units is unknown. Here we investigate, using mitochondrial DNA (mtDNA) mutations as a marker of clonal expansion, the clonality of the gastric unit and show how mutations expand in normal mucosa and gastric mucosa showing intestinal metaplasia. This has important implications in gastric carcinogenesis., Methods: Mutated units were identified by a histochemical method to detect activity of cytochrome c oxidase. Negative units were laser-capture microdissected, and mutations were identified by polymerase chain reaction sequencing. Differentiated epithelial cells were identified by immunohistochemistry for lineage markers., Results: We show that mtDNA mutations establish themselves in stem cells within normal human gastric body units, and are passed on to all their differentiated progeny, thereby providing evidence for clonal conversion to a new stem cell-derived unit-monoclonal conversion, encompassing all gastric epithelial lineages. The presence of partially mutated units indicates that more than one stem cell is present in each unit. Mutated units can divide by fission to form patches, with each unit sharing an indentical, mutant mtDNA genotype. Furthermore, we show that intestinal metaplastic crypts are clonal, possess multiple stem cells, and that fission is a mechanism by which intestinal metaplasia spreads., Conclusions: These data show that human gastric body units are clonal, contain multiple multipotential stem cells, and provide definitive evidence for how mutations spread within the human stomach, and show how field cancerization develops.

Objectives: Intestinal metaplasia (IM) and dysplasia in Barrett's esophagus are recognized surrogates for esophageal adenocarcinoma risk. While few would argue with the "hunt for dysplasia," there is a divide regarding the usefulness of the histological confirmation of intestinal metaplasia in endoscopically apparent long segment Barrett's esophagus. We aimed to assess the frequency of intestinal metaplasia in 125 consecutive patients with columnar-lined esophagus and to determine the optimal biopsy protocol to detect intestinal metaplasia., Methods: Two-hundred ninety-six endoscopies were performed over a 4-yr period in Barrett's esophagus segments of mean length 4 cm (range 1-11 cm) at a single center and the resulting biopsies were analyzed retrospectively. Biopsies were all processed with routine hematoxylin and eosin (H&E) staining, and a subset (N=92) was subject to alcian blue/periodic-acid Schiff staining., Results: Using H&E staining, we found that the optimum number of biopsies to diagnose intestinal metaplasia was 8 per endoscopy, mean 67.9% endoscopies having intestinal metaplasia. In contrast, if only four were taken the yield was 34.7% with intestinal metaplasia. Unless more than 16 biopsies were taken (100% yield of intestinal metaplasia), no additional significant detection was achieved. Using additional alcian blue/periodic-acid Schiff staining only had a marginal benefit, with 5.4% of new cases of intestinal metaplasia being identified. There is a proximal cephalo-caudal gradient of intestinal metaplasia, especially with increased chronological age, but doing repeat endoscopies on patients did not increase the detection of intestinal metaplasia., Conclusions: The data suggest that at least 8 random biopsies is the minimum to be taken and analyzed with conventional H&E staining to diagnose benign intestinal metaplasia. Taking more biopsies did not statistically increase the diagnosis of intestinal metaplasia except when greater than 16 were taken when 100% yield was obtained.

Colorectal cancer is a major cause of mortality and treatment costs are considerable. Advocating lifestyle modification, faecal occult blood testing and surveillance colonoscopy in appropriate populations are already in practice. A developing concept is chemoprevention. Several models of carcinogenesis in colorectal cancer have been developed and there is an increasing database on the major molecular mechanisms involved in carcinogenesis mainly from preclinical experiments and phase I trials. There have been several large epidemiological and observational studies to evaluate possible protective effects of >200 agents. More recently, case-control and cohort studies and well-conceived, phase II/III clinical trials have been done or are under way to evaluate putative chemopreventive agents including established drugs like aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), 5-aminosalicylates and statins; more controversial drugs like cyclo-oxygenase-2 (COX-2) inhibitors, ursodeoxycholic acid; various vitamins and micronutrients including calcium, selenium, folic acid, and dietary fibre, fat and protein content. Despite promising outcome in preclinical studies, there is currently very limited data from well-controlled and appropriately powered clinical studies. The most promising agents currently are aspirin, traditional NSAIDs and COX-2 inhibitors. The recent reports of cardiovascular risks of the COX-2 inhibitors and some traditional NSAIDs have resulted in stagnation of the field. Pending the expected release of results from several phase III trials in the near future, chemoprevention for colorectal cancer can only be practically considered in the very-high-risk population like those with familial adenomatous polyposis and ulcerative colitis, in conjunction with surveillance colonoscopy. This article reviews the major models of colorectal carcinogenesis, the concept of chemoprevention with special reference to colorectal cancer and the current state of clinical literature and the future direction of colorectal cancer chemoprevention for both researcher and clinician alike., ((c) 2007 S. Karger AG, Basel.)

Long-standing gastro-oesophageal reflux disease (GORD) can give rise to Barrett's oesophagus (BM), a metaplastic condition and precursor to oesophageal adenocarcinoma (AC). Oesophageal cancer was once rare but is now the 5th biggest cancer killer in the U.K. Reflux of bile acids into the oesophagus is implicated in the progression to BM as bile acids at pH 4 have been shown to induce c-myc expression, an oncogene upregulated in BM and AC. In the present study we investigated the role of the biopolymer alginate on bile acid induced molecular changes in oesophageal cell lines. OE21, OE33 and TE-7 oesophageal cell lines were exposed to 100 microM deoxycholic acid at pH 4 in the presence or absence of alginates. Levels of c-myc, E-cadherin, beta-catenin and Tcf signalling were determined by Real-Time PCR, Western blotting, immunofluoresence and reporter assays. All alginates tested were able to prevent the induction of c-myc by acidified deoxycholic acid in vitro. The upstream effects of acidified deoxycholic acid on E-cadherin, beta-catenin and Tcf signalling were also suppressed by alginate. Therefore, we have demonstrated that reflux of bile acids into the oesophagus initiates a potentially damaging molecular cascade of events using an in vitro model and that a biopolymer, alginate, can protect against these effects.

Background & Aims: Barrett's esophagus (BE) is a premalignant condition for esophageal adenocarcinoma, its diagnosis relying initially on recognition of a columnar-lined distal esophagus. We aimed to develop and validate explicit, consensus-driven criteria for the endoscopic diagnosis and grading of BE., Methods: An international working group agreed on criteria and developed materials for their formal evaluation using video-endoscopic recordings gathered in a standardized manner in 29 patients. The criteria included assessment of the circumferential (C) and maximum (M) extent of the endoscopically visualized BE segment as well as endoscopic landmarks. The recordings were scored according to these criteria by a separate international panel of 29 endoscopists., Results: The Prague C & M Criteria give explicit guidance on the endoscopic recognition of BE and grading of its extent. The overall reliability coefficients (RC) for the assessment of the C & M extent of the endoscopic BE segment above the gastroesophageal junction were 0.95 and 0.94, respectively. The rates of exact agreement (for C & M values) for pairwise comparisons of individual patient values were 53% and 38%, respectively, whereas the values for agreement within a 2-cm interval were 97% and 95%, respectively. The overall RC for endoscopic recognition of BE >/=1 cm was 0.72, whereas for BE <1 cm, it was 0.22. The RCs for recognizing the location of the gastroesophageal junction and the diaphragmatic hiatus were 0.88 and 0.85, respectively., Conclusions: The Prague C & M Criteria have high overall validity for the endoscopic assessment of visualized BE lengths.

Purpose: The incidence of esophageal adenocarcinoma is rising, and survival rates remain poor. The hepatocyte growth factor (HGF) receptor Met has been detected in esophageal cancer. The perturbation of cadherin/catenin complexes has also been shown. We sought to investigate a link among Met expression, cadherin/catenin biology, and cell growth. We assessed the prognostic significance of Met expression in esophageal adenocarcinoma., Experimental Design: Met and HGF expression in esophageal tissues were assessed using immunohistochemistry and ELISA. Met-positive cell lines (OE33 and SEG1) and a Met-negative cell line (TE7) were incubated with HGF. Real-time reverse transcription-PCR and Western blotting were used to assess levels of E-cadherin expression. Nuclear TCF/beta-catenin signaling was assessed following reporter construct transfection. Agar colony formation was used to assess anchorage-independent growth. A panel of 72 resected esophageal adenocarcinomas were assessed for Met expression by immunohistochemistry and correlated to survival data., Results: An increased expression of Met was seen along the metaplasia- adenocarcinoma sequence. Met-positive cells showed reductions in E-cadherin mRNA (37% and 69%) and protein expression following stimulation with HGF (P < 0.01). OE33 and SEG-1 showed up to a 2-fold increase in the levels of beta-catenin nuclear signaling (P < 0.01). TE7 only responded when transfected to express Met; E-cadherin expression decreased by 64% (P < 0.01). HGF stimulation led to increased agar colony formation (P < 0.01). Patients with Met-positive tumors showed lower 6-month survival rates after surgical resection than those with Met-negative tumors (P < 0.05)., Conclusions: Met activation induces changes consistent with early invasion, such as down-regulation of E-cadherin, increased nuclear TCF/beta-catenin signaling, and anchorage-independent growth. This is supported by ex vivo data associating Met with reduced short-term survival. Inhibitors of Met may be effective treatment for esophageal adenocarcinoma.