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Evidence clearly shows a chemopreventive effect for aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) on colorectal cancer and probably other cancer types; however, data on the risk-benefit profile for cancer prevention are insufficient and no definitive recommendations can be made. Aspirin has emerged as the most likely NSAID for use in chemoprevention because of its known cardiovascular benefit and available safety and efficacy data. Other traditional NSAIDs, particularly sulindac, and selective COX-2 inhibitors are now given to patients at high risk of colorectal cancer, although these drugs do not provide cardioprotection. More studies of aspirin and cancer prevention are needed to define the lowest effective dose, the age at which to initiate therapy, the optimum treatment duration, and the subpopulations for which the benefits of chemoprevention outweigh the risks of adverse side-effects. Although it might be possible to answer some of these questions with longer follow-up of existing clinical trials, randomised controlled trials with new study designs will be needed. Future projects should investigate the effects of aspirin treatment on multiple organ systems. Cancers of interest are colorectal, breast, prostate, lung, stomach, and oesophageal. The main side-effect of aspirin is peptic ulcers; therefore coadministration of aspirin with a proton-pump inhibitor is an attractive option and is under investigation in the AspECT trial.

To identify susceptibility loci for visceral leishmaniasis, we undertook genome-wide association studies in two populations: 989 cases and 1,089 controls from India and 357 cases in 308 Brazilian families (1,970 individuals). The HLA-DRB1-HLA-DQA1 locus was the only region to show strong evidence of association in both populations. Replication at this region was undertaken in a second Indian population comprising 941 cases and 990 controls, and combined analysis across the three cohorts for rs9271858 at this locus showed P(combined) = 2.76 × 10(-17) and odds ratio (OR) = 1.41, 95% confidence interval (CI) = 1.30-1.52. A conditional analysis provided evidence for multiple associations within the HLA-DRB1-HLA-DQA1 region, and a model in which risk differed between three groups of haplotypes better explained the signal and was significant in the Indian discovery and replication cohorts. In conclusion, the HLA-DRB1-HLA-DQA1 HLA class II region contributes to visceral leishmaniasis susceptibility in India and Brazil, suggesting shared genetic risk factors for visceral leishmaniasis that cross the epidemiological divides of geography and parasite species.

Barrett's esophagus (BE) is a common lesion that predisposes to a highly fatal esophageal adenocarcinoma (EA). There is evidence that BE or parts of its phenotype are genetically predisposed. Several single-nucleotide polymorphisms (SNPs) have been validated as predisposing to BE but the inherent flaws in the trial sizes, presence of controls and statistical power need circumspect analysis. The current paper links the interleukin 18 cytokine with BE and perhaps EA. Setting aside the issues above there are other issues such as the functional relevance of these SNPs for the association BE. There have been several case control series published indicating other genes. Furthermore, there are some sibling pairs study results with another set of genes identified. Invariably as useful as these studies are the size, scale to answer complex questions (complexity) and potential clinical significance are proportional in genomic studies. The new era of large-scale genome-wide studies in Barrett's and EA is needed. Shortly the first will be published showing two SNPs of significance in 7,838 Barrett's patients.

Sanders D S A, Grabsch H, Harrison R, Bateman A, Going J, Goldin R, Mapstone N, Novelli M, Walker M M & Jankowski J (2012) Histopathology 61, 795–800 Comparing virtual with conventional microscopy for the consensus diagnosis of Barrett’s neoplasia in the AspECT Barrett’s chemoprevention trial pathology audit Aims: To compare the diagnostic accuracy of conventional versus virtual microscopy for the diagnosis of Barrett’s neoplasia. Methods and results: Sixty-one biopsies from 35 ASPirin Esomeprazole ChemopreventionTrial (AspECT) trial patients were given a Barrett’s neoplasia score (1–5) by a panel of five pathologists using conventional microscopy. Thirty-three biopsies positive for neoplasia were digitized and rescored blindly by virtual microscopy. Diagnostic reliability was compared between conventional and virtual microscopy using Fleiss’ kappa. There was substantial reliability of diagnostic agreement (κ = 0.712) scoring the 61 biopsies and moderate agreement scoring the subgroup of 33 ‘positive’ biopsies with both conventional microscopy (κ = 0.598) and virtual microscopy (κ = 0.436). Inter-observer diagnostic agreement between two pathologists by virtual microscopy was substantial (κ = 0.76). Comparison of panel consensus neoplasia scores between conventional and virtual microscopy was almost perfect (κ = 0.8769). However, with virtual microscopy there was lowering of the consensus neoplasia score in nine biopsies. Conclusions: Diagnostic agreement with virtual microscopy compares favourably with conventional microscopy in what is recognized to be a challenging area of diagnostic practice. However, this study highlights possible limitations for this method in the primary diagnostic setting.

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.

Barrett’s oesophagus normally affects the distal oesophagus when metaplastic columnar lined epithelium replaces stratified squamous epithelium which predisposes to cancer development. This develops as a consequence of chronic gastroesophageal reflux (GORD). Those with Barrett’s have a 40 fold increased risk of oesophageal adenocarcinoma [1] . There are is still a lack of understanding of the natural history of the cell of origin. This does hamper research into this area. We accept that there is a limitation in testing of the pathogenesis of Barrett’s oesophagus due to a lack of a universally accepted animal model. The major questions surrounding Barrett’s oesophagus include validity of surveillance strategies, the optimal treatment and more importantly an agent that can prevent progression to cancer without unacceptable side effects. The main chemopreventative agents that show promise are aspirin and proton pump inhibitors (PPIs). There are other agents such as green tea, berries and antioxidants and diet that have been suggested; we discuss the evidence available for these strategies. We hope for continued improvement in the clinical trial infrastructure to facilitate testing of new pharmacological and endoscopic interventions for Barrett’s oesophagus.

Bulimia nervosa and other eating disorders have been on the increase for the past half century. Self-induced vomiting is often practiced as a method of weight control in these patients, potentially causing acidic damage to the esophagus of the kind observed in cases of gastroesophageal reflux disease. To ascertain whether patients suffering from bulimia nervosa had an increased rate of reflux-related symptoms, potentially placing them at risk of developing sequelae such as Barrett's esophagus and esophageal adenocarcinoma, a literature review was performed via searches of databases including PubMed, Medline, OVID and PsycINFO and a recursive search of the literature. The search terms were: bulimia nervosa; reflux; esophageal adenocarcinoma; Barrett's esophagus; eating disorders; oral; dental; complications. Several case reports were identified detailing the occurrence of an esophageal tumor in patients with a history of bulimia. This was supported to some degree by studies detailing higher incidences of reflux symptoms in eating disordered patients compared to controls but there was large variability in study design, quality and results. From these results an association is suggested as possible but is far from being proved conclusively. Further investigation is required using larger patient groups, better study design controlling for confounding factors and symptom characterisation.

and oncologic treatment, prognosis of those diagnosed with EAC remains poor, with an overall 5-year survival of less than 15%. The main risk factor for EAC is the premalignant condition of Barrett’s esophagus (BE). BE is common, affecting 10% to 15% of those who undergo upper gastrointestinal endoscopy for reflux symptoms. Its incidence is rising. 2 BE is also underdiagnosed; with an autopsy study finding for every known case, 20 remain undiagnosed. 3 Progression from BE to EAC occurs at a rate of 0.5% to 1% per patient year of follow-up 4,5 and patients have a 30- to 125-times increased risk of developing EAC compared with the general population. Those most at risk include white men of increasing age; smokers; those with frequent, severe reflux of long duration; and those with low fruit and vegetable intake with a raised body mass index (BMI). Helicobacter cagA strain is thought to be protective. Incidence of EAC is highest in the United Kingdom (5.8 to 8.7 per 100,000), followed by Australia (4.8 per 100,000), Netherlands (4.4 per 100,000), and the United States (3.7 per 100,000). 6 The progression from Barrett to adenocarcinoma occurs via a multistep process through squamous epithelium to columnar-lined epithelium, specialized intestinal metaplasia to low-grade dysplasia (LGD), high-grade dysplasia (HGD), and adenocarcinoma with later invasion and metastasis. This process is thought to develop slowly over several years, which

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.

Background: The aim of this study was to develop a model of inflammatory bowel disease (IBD) in zebrafish larvae, together with a method for the rapid assessment of gut morphology and function in vivo thereby enabling medium-throughput compound screening. Methods: Assays were performed using larval zebrafish from 3–8 days postfertilization (d.p.f.) in 96-well plates. Gut morphology and peristalsis were observed in vivo using fluorescent imaging following ingestion of fluorescent dyes. IBD was induced by addition of 2,4,6-trinitrobenzenesulfonic acid (TNBS) to the medium within the well. Pathology was assessed in vivo using fluorescent imaging and postmortem by histology, immunohistochemistry, and electron microscopy. Therapeutic compounds were evaluated by coadministration with TNBS. Results: A novel method of investigating gut architecture and peristalsis was devised using fluorescent imaging of live zebrafish larvae. Archetypal changes in gut architecture consistent with colitis were observed throughout the gut. Significant changes in goblet cell number and tumor necrosis factor alpha (TNF-α) antibody staining were used to quantify disease severity and rescue. Prednisolone and 5-amino salicylic acid treatment ameliorated the disease changes. Candidate therapeutic compounds (NOS inhibitors, thalidomide, and parthenolide) were assessed and a dissociation was observed between efficacy assessed using a single biochemical measure (TNF-α staining) versus an assessment of the entire disease state. Conclusions: Gut physiology and pathology relevant to human disease state can be rapidly modeled in zebrafish larvae. The model is suitable for medium-throughput chemical screens and is amenable to genetic manipulation, hence offers a powerful novel premammalian adjunct to the study of gastrointestinal disease. (Inflamm Bowel Dis 2010)

Norwood M G A, Bailey N, Nanji M, Gillies R S, Nicholson A, Ubhi S, Darnton J J, Steyn R S, Womack C, Hughes A, Hemingway D, Harrison R, Waters R & Jankowski J A (2010) Histopathology 57, 101–111 Cytoplasmic β-catenin accumulation is a good prognostic marker in upper and lower gastrointestinal adenocarcinomas Aims: β-Catenin is an important molecule in cancer biology. Membranous β-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 β-catenin expression. Increasing β-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 β-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 β-catenin in gastrointestinal adenocarcinoma. It shows that low levels of cytoplasmic β-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 β-catenin could be used as a prognostic marker for less aggressive disease.

BackgroundBarrett'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.MethodsWe undertook detailed serological and tissue assessment of gastrin and CCK2 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.ResultsGastrin and its cognate receptor CCK2R were expressed highest in the stomach, then less in Barrett's oesophagus and least in squamous oesophagus (SqE) (n=20 paired t-test, pcckr Barrett's oesophagus cells, but not OE21(E)cckr squamous cells, transfected with CCK2R; migration was induced by 1 ng/ml of gastrin but proliferation only increased with 100 ng/ml (paired t-test, pConclusionWhile 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.

Colorectal cancer is a major cause of cancer-related mortality. Most colorectal cancers arise in precursor lesions over a number of years. The carcinogenetic pathway is modulated by a wide array of genetic and epigenetic factors. Two major approaches to halting carcinogenesis are chemoprevention and early detection. Chemoprevention is an attractive emerging option—advances in understanding the carcinogenetic pathways and progress in evaluating various putative agents are promising. However, several issues regarding efficacy, safety, and acceptability require answers before an ideal agent can come into widespread use. Early detection and removal of precursor lesions show promise in reducing disease burden. Although the concept has been around and has been widely advocated for several years, participation in screening remains low. The ideal test in terms of practicality, accuracy, and safety is still debated. This article reviews the recent literature related to screening and chemoprevention of colorectal cancer.

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.

SUMMARY Barrett's esophagus (BE) may be an adaptive cellular response to repeated acid exposure. The aims of this study were to compare intracellular acid loading in BE cells with normal squamous esophageal cells. Primary squamous and BE cells were obtained endoscopically and cultured for up to 24 h. Barrett's adenocarcinoma cell lines TE7 and OE-33 were compared with a normal esophageal (NE) cell line OE-21. Extracellular pH was lowered to 6.0 using HCl; specific ion exchangers were blocked pharmacologically and pH microfluorimetry was performed using 2'7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. The effect of prolonged acid preincubations and repeated acid exposure on acid loading and recovery were examined. Acid loading was greater in primary BE than NE cells (DeltapHi -0.22 +/- 0.08 vs.-0.13 +/- 0.01) and maximal in the BE carcinoma cell line TE7 (DeltapHi -0.30 +/- 0.01). Whereas TE7 cells were able to recover fully from repeated acid exposure, OE-21 cells remained profoundly acidic. BE primary and transformed cells utilize DIDS inhibitable sodium-independent chloride/bicarbonate exchange as well as sodium/hydrogen ion exchange for acid loading. In contrast, SE only requires sodium-independent chloride/bicarbonate exchange for acidification. The degree of acid loading is greater in BE than NE cells and it occurs via dual ion exchangers similar to gastric mucosa. Only Barrett's epithelial cells can maintain a physiological pHi following prolonged and repeated reflux exposure, which may confer a teleological advantage.

Aspirin is the best chemoprevention agent for colorectal cancer risk reduction despite the fact that the evidence for a decrease in mortality is weak. The cyclooxygenase-2 selective agents (COXIBS) have an efficacy similar to that of aspirin for most gastrointestinal (GI) lesions but not esophagus. Specifically, there are beneficial short term effects of COXIBs on the risk of colorectal adenoma as shown in the Approve, PreSAP, and APC studies. However, there is still an increased risk of upper GI complications with COXIBs when compared with placebo, and this risk may increase further in some people when aspirin is also consumed. Whereas aspirin reduces the risk of cardiovascular events, COXIBs and most traditional nonsteroidal anti-inflammatory drugs (but not all) are both associated with an increased risk of thrombotic cardiovascular events compared with placebo. In conclusion, COXIBs have a niche role for patients with familial adenomatous polyposis. The value of aspirin remains with respect for efficacy, mainly in the esophagus, and the side effect profile, especially in the elderly if given with acid suppression therapy. COXIBs should be used in younger populations, but if they are considered in the elderly because of increased GI risks, and the cardiovascular risk is also increased, then combination treatment with aspirin and a proton-pump inhibitor should also be considered instead, such as in the ASPECT trial. (Cancer Epidemiol Biomarkers Prev 2008;17(8):1858–61)

To assess the variation in practice of Barrett's esophagus (BE) management in comparison with accepted international guidelines before and after the introduction of a large BE randomized controlled trial (RCT) with protocols including those of tissue sampling.A validated anonymized questionnaire was sent to 401 senior attending gastroenterologists asking for details of their current management of BE, especially histological sampling. Of the 228 respondents, 57 individuals (each from a different center) were in the first group to enter the ASPirin Esomeprazole (BE) Chemoprevention Trial (AspECT), and we assessed change in practice in these centers.Ninety percent of specialists did not take adequate biopsies for histological diagnosis. Furthermore, 74% would consider aggressive surgical resection for prevalent cases of high-grade dysplasia in BE as their first-line choice despite the associated perioperative mortality. Ninety-two percent claim their lack of adherence to guidelines is because there is a need for stronger evidence for surveillance and medical interventions. Effect of the AspECT trial: Those clinicians in centers where the AspECT trial has started have improved adherence to ACG guidelines compared with their previous practice (P0.05). BE patients now get 18.8% more biopsies compared with previous practice, and 37.7% if the patient is entered into the AspECT trial (P0.01).This large study indicates both wide variation in practice and poor compliance with guidelines. Because optimal histology is arguably the most important facet of BE management, the improvement in practice in centers taking part in the AspECT trial indicates an additional value of large international RCTs.

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 beta-catenin as grade and stage of bladder TCC progress, accompanied by a significant increase in P-cadherin expression (all p < 0.05, Pearson's chi2 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.

Barrett's esophagus (BE) is a frequent complication of gastroesophageal reflux disease, an acquired condition resulting from persistent mucosal injury to the esophagus. The incidence of Barrett's metaplasia and Barrett's adenocarcinoma has been increasing, but the prognosis of Barrett's adenocarcinoma is worse because individuals present at a late stage. Attempts have been made to intervene at early stage using surveillance programmes, although proof of efficacy of endoscopic surveillance is lacking. There is much to be learned about BE. Whether adequate control of gastroesophageal reflux early in the disease alters the natural history of Barrett's change once it has developed remains unanswered. Thus there is great need for carefully designed large randomised controlled trials to address these issues in order to determine how best to manage patients with BE. The AspECT and BOSS clinical trials proride this basis.

Summary Background Patients with Barrett’s oesophagus are at increased risk of oesophageal adenocarcinoma. Observational studies have suggested increase in overall mortality also but data are conflicting. Aim To assess the cause of death in patients with Barrett’s oesophagus compared with the general population. Methods Patients with Barrett’s oesophagus were identified retrospectively in four hospitals in Leicestershire, UK using electronic endoscopy and histopathology records from 1997 to 2003. Data on deaths from this cohort of patients were identified through the Office of National Statistics and compared with age– and gender-adjusted mortality in the Leicestershire region. Results In all, 1272 Barrett’s patients were identified with 245 deaths in this cohort. Overall mortality was found to be increased [male standardized mortality ratio (SMR) = 552, 95% CI = 466–638; female SMR 455, 95% CI = 357–552]. The main disease areas that were responsible for this increase were oesophageal adenocarcinoma (n = 25, male SMR = 2171, 95% CI = 991–3351; female SMR = 1300, 95% CI = 26–2574), bronchopneumonia (n = 70, male SMR = 146, 95% CI = 55–236; female SMR = 436, 95% CI = 272–601) and ischaemic heart disease (n = 51, male SMR = 186, 95% CI = 97–2748; female SMR = 205, 95% CI = 105–306). Conclusions Patients with Barrett’s oesophagus die more commonly of bronchopneumonia and ischaemic heart disease compared with oesophageal adenocarcinoma, and overall mortality in this group may be increased.

Aim A world-wide recognised and accepted definition and classification of gastroesophageal reflux disease (GERD) would be highly desirable for research and clinical practice. The purpose of this project was to develop such a generally accepted definition and classification that could be used equally by patients, physicians, and supervisory bodies. Methods In order to ensure a consensus among the participating experts a modified delphi process with a step-wise selection modality was employed. For this the working group of five persons formulated a series of statements on the basis of a systematic search of the literature using three databases (Embase, Cochrane-Study register, Medline). Then these statements were developed further for two years, revised and finally passed as consensus. The consensus group consisted of 44 experts from 18 countries. Each key vote was held on the basis of a six-point scale. A "consensus" was considered to have been reached when two-thirds of the participants voted in favour of the respective statement. Results The level of agreement between the experts increased in the course of the multistep decision process, in the individual voting steps requiring at least two-thirds of the participants, the results were at first 86%, then 88% through to 94% and finally 100% in favour of the chosen statement. In the final voting, 94% of the final 51 statements were accepted by 90% of the consensus group. 90% of all statements were accepted unanimously or with only minor reservations. GERD was defined as a disease that is associated with troublesome symptoms and/or complications on account of reflux of stomach contents into the esophagus. The complaints are divided into esophageal and extra-esophageal syndromes. Among the novel aspects of this definition are the patient-orientated approach that is independent of endoscopic findings, the classification of the ailment into independent syndromes as well as the consideration of laryngitis, cough, asthma and dental problems as possible GERD syndromes. Furthermore, a new definition of suspected or demonstrated Barrett's esophagus is proposed. Conclusion Irrespective of country-specific differences in terminology, language, prevalence and manifestations of this disease, evidence-based, world-wide valid consensus definitions are possible. A global consensus definition of GERD will simplify disease management, make mutual research possible and help in the design of generally valid studies. This will not only help the patient but also the physician and supervisory bodies.

Barrett's oesophagus is a frequent complication of gastro-oesophageal reflux disease predicting oesophageal adenocarcinoma. The majority of Barrett's patients will not develop cancer, so that specific methods of identification of those at risk are required. Recent molecular studies have identified a selection of candidate biomarkers that need validation in prospective studies. They reflect various changes in cell behaviour during neoplastic progression. The ASPECT trial in the UK aims to establish whether chemoprevention with aspirin and a proton pump inhibitor will reduce adenocarcinoma development and mortality in patients with Barrett's oesophagus. It will also validate biomarkers for progression and clinical response and further study disease pathogenesis.

Gastrointestinal cancer accounts for approximately 25% of all cancers and approximately 9% of all deaths worldwide. Cancer is the cause of death in 25% of cases in the United Kingdom compared with 22% in the United States. Although death rates of most of the top 10 cancers have decreased in the last decade, male esophageal cancers are on the rise (3% increase). Screening the population for Barrett metaplasia is not cost-effective exercise especially if patients are asymptomatic. Moreover, though surveillance is now widely done for Barrett metaplasia both for short-segment and long-segment, the incidence of esophageal cancer is much higher than expected, as most of these do not come to light until late in the elderly. The best therapeutic strategy hence would be chemoprevention. This review paper mainly addresses the issues such as the epidemiology of adenocarcinoma in Barrett esophagus; the rationale for prevention; why chemoprevention would be the best option and will describe the major trial on chemoprevention in Barrett Metaplasia (Aspirin Esomeprazole Chemoprevention Trial).

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.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 (HE) staining, and a subset (N=92) was subject to alcian blue/periodic-acid Schiff staining.Using HE 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.The data suggest that at least 8 random biopsies is the minimum to be taken and analyzed with conventional HE 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.

It was previously though that adenomas gave rise to colorectal cancers and that other polyps were harmless. Serrated polyps—hyperplastic polyps, serrated adenomas, and sessile serrated adenomas—show distinct patterns of genetic and epigentic mutation that suggest their role in an alternative pathway of colorectal cancer development. In parallel with these findings are improved demographic and histologic data that also indicate that a subset of serrated polyps are precursors of cancer.

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.

Prevention is the most desirable strategy for nearly all disease processes, but this is especially true for a malignancy with a tendency for metastasis and a correspondingly poor prognosis. Chemoprevention through appropriate drug treatment is a potentially powerful means of radically reducing the incidence of esophageal cancer, and the search for clinically effective agents has now led to large multicenter randomized controlled trials.

The inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, result from an altered host response to intestinal flora, and genome-wide searches have identified a number of disease susceptibility alleles, such as NOD2/CARD15. IBD confers a high risk of development of a number of malignancies, especially colorectal cancer, and this risk is related to chronic inflammation. Genomic instability in the form of gross chromosomal changes is common, with microsatellite instability occurring in a small subset of colitis-associated lesions. The carcinogenesis pathway in colitis-associated cancers is less clearly understood than its sporadic counterpart. Mutations in the APC gene appear to be less frequent and occur later, whereas inflammation-induced p53 mutations are found early in nondysplastic tissue. Selection and clonal expansion of inflammation-induced mutations is likely to account for the high mutational load seen in carcinoma tissue. Development of an effective biomarker to predict development of malignancy in colitis has so far been unsuccessful. Copyright © 2006 by Current Science Inc.

A method of solving three-dimensional coupled quasi-static problems of linear thermoelasticity is presented. Any initial-boundary value problem contains a coupled initial state. The concept is based on extending a region occupied by the considered body over the whole space where the space value thermoelastic problem is formulated. Both the Helmholtz displacement potentials and temperature from the space value Helmholtz problem are convolutionally determined. All the outside component parts of the convolution products are here defined as fictitious ones. The solution of space value thermoelastic problem includes fictitious displacement-temperature components. Capacities of approximate fictitious components are calculated from the boundary condition contracted to the finite time interval. Approximate solution to the primary thermoelasticity problem is obtained by spatial contracting of the solution to the space value thermoelastic problem.

Over the past decade, the advances in our understanding of stem cell biology and the role of stem cells in diseases, such as colorectal cancer, have been remarkable. In particular, discoveries related to the control of stem cell proliferation and how dysregulation of proliferation leads to oncogenesis have been foremost. For intestinal stem cells, the WNT family of growth factors, and events such as the regulation of the nuclear localization of beta-catenin, seem to be central to normal homeostasis, and mutations in the components of these pathways seem to lead to the development of colorectal cancer. A paradigm of abnormal stem cell biology is illustrated by patients with familial adenomatous polyposis, who have mutations in the adenomatous polyposis coli gene. The wild-type protein encoded by this gene is important for the prevention of mass beta-catenin accumulation in the nucleus and the subsequent overtranscription of cell cycle proteins. This review discusses the basic mechanisms behind stem cell regulation in the gut and follows their role in the natural history of tumor progression.

Oesophageal adenocarcinoma (OA) remains one of the more deadly forms of gastro-intestinal cancer with a mortality rate exceeding 90%. The incidence of OA remains unabated and has a reported fivefold increase since 1970 [Pera M, Cameron AJ, Trastek VF, Carpenter HA & Zinsmeister AR. Increasing incidence of adenocarcinoma of the esophagus and esophagogastric junction. Gastroenterology 1993; 104 (2) : 510–513]. Gastro-oesophageal reflux disease and its sequelae, Barrett's oesophagus, is one of the principle risk factors in the development of OA, with a 30-fold increased risk in Barrett's patients compared with the general population [Tytgat GNJ. Does endoscopic surveillance in esophageal columnar metaplasia (Barretts-Esophagus) have any real value. Endoscopy 1995; 27 (1) : 19–26]. OA is thought to be a microcosm of evolution, developing sequentially along the metaplasia–dysplasia–adenocarcinoma sequence. Progression is attributed to a series of genetic and epigenetic events that ultimately allow for clonal selection of Barrett's cells via subversion of intrinsic control mechanisms regulating cellular proliferation and/or apoptosis. This review will describe the current suppositions of the mechanisms behind the selection and subsequent expansion of Barrett's clones, and focus on some of the principle hallmarks associated with this transition.

The work includes a proposal of solving coupled quasi-static problems of linear thermoelasticity with coupled initial state by Helmholtz potentials. The proposal is based on an extension of the body region to the whole space where the space integral as a particular solution of the Helmholtz initial-boundary value problem is derived. Thermomechanical fictitious sources are separated from the space integral. Their capacities are determined on an approximate way from the boundary conditions in a bounded time interval. The approximated solution of the initial-boundary value problem of thermoelasticity was obtained by contraction of the space integral in space and time.

Esophageal adenocarcinoma (EAC) is a relatively uncommon but serious cancer afflicting 5 – 15 /100000 population in the UK, and in which diagnosis at the late rather than the early stage decreases the 5-year survival rates from 90 % to between 10 % and 20 % 1 . Barrett’s esophagus is present as a premalignant lesion in the majority of cases of EAC and although Barrett’s esophagus is a major risk factor, only 2.5 % – 5 % of cases progress to EAC. The increased risk generally initiates a program of endoscopic surveillance that enables early intervention if the disease progresses 2 .

Mechanisms by which premalignant Barrett’s metaplasia (BM) progresses to esophageal adenocarcinoma are currently being sought. This study investigated the role played by the polypeptide hormone gastrin, specifically its antiapoptotic effects through activation of protein kinase B/Akt (PKB/Akt). In esophageal cell lines with low basal levels of activated PKB/Akt, phosphorylation could be induced by exogenous amidated gastrin. High basal levels of activated PKB/Akt were linked to endogenous gastrin expression and were reduced by treatment with a cholecystokinin-type 2 receptor (CCK-2R) antagonist. Expression of a constitutively active splice variant of the CCK-2R additionally increased basal activation of PKB/Akt. It is proposed that gastrin acting in an autocrine and endocrine manner via a CCK-2R isoform may activate PKB/Akt and that with expression of gastrin and CCK-2R isoforms increasing in BM samples, gastrin may aid progression of BM through amplification of antiapoptotic pathways. Evidence for this proposal was provided through the observed specific up-regulation of PKB/Akt in BM samples.

Recent research has led to a much greater understanding of the molecular mechanisms driving the neoplastic progression of Barrett's oesophagus (columnar-lined oesophagus, CLO) metaplasia through grades of dysplasia to adenocarcinoma, with the promise of future novel diagnostic techniques and therapies to help counter the striking increased incidence and mortality reported for CLO-related cancer in the West. Key genetic changes include telomerase re-activation, loss of p53 expression (by mutation or deletion) loss of p16 gene expression (by mutation or hypermethylation), increased cyclin D1 expression and aneuploidy. However, until relevant and reliable molecular diagnostic aids come into routine diagnostic practice, the onus on accurate disease monitoring remains based on morphology, highlighting the need for accurate and reproducible criteria for the histopathological diagnosis of pre-malignant and malignant mucosal changes in the metaplasia–dysplasia–carcinoma sequence of CLO.

Background & Aims: Factors associated with the development and malignant progression of Barrett's esophagus are poorly understood. Gastrin is a mitogen capable of inducing growth in normal and malignant gastrointestinal mucosa. It is unknown whether gastrin can influence cellular events in the esophagus in Barrett's. Methods: Reverse-transcription polymerase chain reaction (RT-PCR) and northern analysis for the cholecystokinin (CCK 2 ) receptor were performed on normal, inflamed, metaplastic, and malignant esophageal mucosa. Real-time PCR quantified expression of the receptor. [ 125 I]-G17-autoradiography localized the CCK 2 receptor in mucosal sections. [ 3 H]-thymidine and bromodeoxyuridine (BrdU) incorporation determined proliferation in response to G17 in biopsy specimens incubated ex vivo. Proliferation and signaling studies were performed on OE33(E) cells transfected with the CCK 2 receptor. Results: RT-PCR identified receptor expression in 3 of 9 controls, 5 of 7 patients with esophagitis, 10 of 10 patients with Barrett's metaplasia, and 7 of 12 esophageal adenocarcinomas. Real-time PCR quantified expression in 10 patients with Barrett's showing a level of expression 2 orders of magnitude higher than in 12 control patients. [ 125 I]-G17 bound to epithelia within glandular regions of Barrett's mucosa. Ten nmol/L G17 induced a 2-fold (n = 7, P = 0.0257, t test) increase in [ 3 H]-thymidine incorporation in mucosal biopsy specimens, abolished by the addition of the CCK 2 receptor antagonist L-740, 093. One nmol/L G17 induced a 1.94– ± 0.13-fold (n = 6, t test, P = 0.001) increase in [ 3 H]-thymidine incorporation in OE33(E) GR cells, abolished by L-740, 093. Conclusions: Gastrin induces proliferation via the CCK 2 receptor in Barrett's mucosa. This may have implications for the management of patients with Barrett's esophagus in whom gastrin is elevated by acid-suppression therapy. GASTROENTEROLOGY 2003;124:615-625

Barrett's metaplasia (BM) is an early lesion in the progression from oesophageal inflammation through dysplasia to the development of Barrett's adenocarcinoma (BA). Previous work indicates that BM and BA are associated with reduced E-cadherin expression and increased cytoplasmic/nuclear pools of its associated protein beta-catenin. beta-catenin participates in Wnt signalling and activates oncogene transcription by complexing with T-cells factors (TCF). One such oncogene is c-myc. We have previously shown that TNF-alpha can down-regulate E-cadherin expression. Here, we assess TNF-alpha expression in Barrett's metaplasia and examine if TNF-alpha can promote beta-catenin mediated transcription of oncogenes in a gastrointestinal model system. Employing immunohistochemistry and Western blot analysis of oesophageal tissue, epithelial expression of TNF-alpha increases with progression along the metaplasia-dysplasia-carcinoma sequence (P

Background: Colorectal adenomatous and, probably, hyperplastic polyp development requires epithelial remodelling and stratification, with loss of E-cadherin expression implicated in adenoma formation. We have shown that P-cadherin, normally expressed in stratified epithelia and placenta, is aberrantly expressed in disturbed epithelial architecture associated with colitis. Aims: (i) To investigate the role of P-cadherin in colonic polyp formation. (ii) To ascertain whether expression of P-cadherin is independent of or correlated with expression of its associated proteins— E-cadherin, β-catenin, and γ-catenin. (iii) To determine if P-cadherin is functional regarding catenin binding in polyps. Methods: Expression and localisation of cadherins (E- and P-) and their associated catenins (β- and γ-) were determined in aberrant crypt foci (ACF), in polyps with hyperplastic morphology (hyperplastic polyps and serrated adenomas), and in adenomatous polyps by immunohistochemistry, western blotting, and mRNA in situ hybridisation. Assessment of cadherin-catenin binding was evaluated by co-immunoprecipitation. Adenomatous polyposis coli (APC) mutation was assessed in adenomatous polyps. Results: P-cadherin was expressed from ACF through to hyperplastic and adenomatous polyps. Alterations in E-cadherin and catenin expression occurred later, with variant patterns in (i) ACF, (ii) hyperplastic polyps and serrated adenomas, and (iii) adenomatous polyps. P-cadherin present in adenomas was functional with regard to catenin binding, and its expression was independent of APC mutational status. Conclusions: P-cadherin is aberrantly expressed from the earliest morphologically identifiable stage of colonocyte transformation, prior to changes in E-cadherin, catenin, and APC expression/mutation. P-cadherin expression alone does not predict tissue morphology, and such expression is independent of that of associated cadherins and catenins.

Development of Quality Indicators for Endoscopic Eradication Therapies in Barrett’s Esophagus: The TREAT-BE (Treatment With Resection and Endoscopic Ablation Techniques for Barrett’s Esophagus) Consortium

Objectives The absolute annual risk of patients with Barrett's oesophagus (BO) developing oesophageal adenocarcinoma (OAC) is ≤0.5%. Screening BO patients for malignant progression using endoscopic surveillance is widely practised. To assess the efficacy and cost-effectiveness of this, we developed a protocol for a randomized controlled trial of surveillance versus ‘at need’ endoscopy. Methods In a multicentre trial, 3400 BO patients randomized to either 2-yearly endoscopic surveillance or ‘at need’ endoscopy will be followed up for 10 years. Urgent endoscopy will be offered to all patients who develop symptoms of dysphagia, unexplained weight loss >7lb (3.2kg), iron deficiency anaemia, recurrent vomiting, or worsening upper gastrointestinal symptoms. Participants must have endoscopically and histologically confirmed BO, with circumferential BO ≥1cm or maximal tongue/island length ≥2 cm. Candidates with existing oesophageal high-grade dysplasia or cancer, or previous upper gastrointestinal cancer will be excluded. Primary outcome will be overall survival. Secondary outcomes will be cost effectiveness (cost per life year saved and quality adjusted life years); cancer-specific survival; time to OAC diagnosis and stage at diagnosis; morbidity and mortality related to any interventions; and frequency of endoscopy. Conclusions This randomized trial will provide data to evaluate the efficacy and cost-effectiveness of screening BO patients for OAC.

Summary Background Evidence is scarce for the effectiveness of therapies for oesophageal cancer progressing after chemotherapy, and no randomised trials have been reported. We aimed to compare gefitinib with placebo in previously treated advanced oesophageal cancer. Methods For this phase 3, parallel, randomised, placebo-controlled trial, eligible patients were adults with advanced oesophageal cancer or type I/II Siewert junctional tumours, histologically confirmed squamous-cell carcinoma or adenocarcinoma, who had progressed after chemotherapy, with WHO performance status 0–2, and with measurable or evaluable disease on CT scan. Participants were recruited from 48 UK centres and randomly assigned (1:1) to gefitinib (500 mg) or matching placebo by simple randomisation with no stratification factors. Patients, clinicians, and trial office staff were masked to treatment allocation. Treatment continued until disease progression, unacceptable toxicity, or patient choice. The primary outcome was overall survival, analysed by intention to treat. This trial is registered, number ISRCTN29580179. Findings Between March 30, 2009, and Nov 18, 2011, 450 patients were randomly assigned to treatment groups (one patient withdrew consent; 224 patients allocated gefitinib and 225 allocated placebo included in analyses). Overall survival did not differ between groups (median 3·73 months, 95% CI 3·23–4·50, for gefitinib vs 3·67 months, 95% CI 2·97–4·37, for placebo; hazard ratio [HR] 0·90, 95% CI 0·74–1·09, p=0·29). Among the prespecified patient-reported outcomes (110 patients on gefitinib and 121 on placebo completed both baseline and 4 week questionnaires and were included in analyses), odynophagia was significantly better in the gefitinib group (adjusted mean difference −8·61, 95% CI −14·49 to −2·73; n=227; p=0·004), whereas the other outcomes were not significantly improved compared with placebo: global quality of life (2·69, 95% CI −2·33 to 7·72, n=231, p=0·293), dysphagia (−3·18, 95% CI −8·36 to 2·00, n=231, p=0·228), and eating (−4·11, 95% CI −9·96 to 1·75, n=229, p=0·168). Median progression-free survival was marginally longer with gefitinib than it was with placebo (1·57 months, 95% CI 1·23–1·90 in the gefitinib group vs 1·17 months, 95% CI 1·07–1·37 in the placebo group; HR 0·80, 95% CI 0·66–0·96, p=0·020). The most common toxicities were diarrhoea (36 [16%] of 224 patients on gefitinib vs six [3%] of 225 on placebo) and skin toxicity (46 [21%] vs two [1%]), both mostly grade 2. The commonest grade 3–4 toxicities were fatigue (24 [11%] vs 13 [6%] patients) and diarrhoea (13 [6%] vs two [1%]). Serious adverse events were reported in 109 (49%) of 224 patients assigned to gefitinib and 101 (45%) of 225 on placebo. 54 (24%) of patients in the gefitinib group achieved disease control at 8 weeks, as did 35 (16%) of patients on placebo (p=0·023). Interpretation The use of gefitinib as a second-line treatment in oesophageal cancer in unselected patients does not improve overall survival, but has palliative benefits in a subgroup of these difficult-to-treat patients with short life expectancy. Future research should focus on identification of predictive biomarkers to identify this subgroup of benefiting patients. Funding Cancer Research UK.

To further examine the function of the trefoil factor family (TFF), the expression of which is up-regulated at sites of injury, we have produced transgenic mice that chronically express rat TFF3 within the jejunum (using a rat fatty acid-binding protein promoter). The expression of rat TFF3 was limited to the villi of the jejunum and had no effect on base-line morphology. Rat TFF3 expression did result, however, in a reduced sensitivity to indomethacin (85 mg/kg subcutaneously), which only caused a 29% reduction in villus height in transgenics versus 51% reduction in controls (p0.01). Indomethacin increased initial intestinal epithelial cell proliferation and migration, but the presence of rat TFF3 caused no additional change in proliferation (bromodeoxyuridine), cell migration ([(3)H]thymidine and bromodeoxyuridine), apoptosis (terminal deoxyuridine nucleotidyl nick end labeling), or E-cadherin immunostaining. In vitro studies following changes in resistance of intestinal strips in Ussing chambers (voltage-clamp technique) showed increased base-line resistance in the rat TFF3-expressing region (326 +/- 60 versus 195 +/- 48 ohm.cm(2) in controls, p0.05) and reduced the fall in resistance following HCl exposure by about 40% (p0.01). Overexpression of TFF3 stabilizes the mucosa against noxious agents, supporting its role in mucosal protection/repair. It may therefore provide a novel approach to the prevention and/or treatment of intestinal ulceration.

The rate of oesophageal adenocarcinoma is increasing in the western world and has a poor prognosis mainly because individuals present at a late stage. Attempts to intervene at an early stage of tumour progression have not proven cost effective, although lesions identified during surveillance programmes have a better prognosis. As a consequence, there has been renewed interest in strategies that might prevent the precursor lesion Barrett's oesophagus. Furthermore, there is an improved understanding of genetic and environmental interactions necessary for the clonal expansion and propagation of metaplastic premalignant lesions. Clearly, three mechanisms promote cancer progression--inheritance of germ-line mutations or polymorphisms, sporadic mutagenesis, and local epigenetic alterations. Locally produced cytokines and bile acids in the refluxate create a microenvironment that sets the scene for metaplastic transformation of the oesophageal epithelium, mainly by directly affecting metaplastic stem cells.

The recognition of key roles for cadherins in the determination of epithelial cell phenotype, migration, differentiation, and tumour dissemination have stimulated much interest in this family of adhesion molecules. In the gastrointestinal tract, alteration of the expression of classical cadherins with aberrant P-cadherin up-regulation, associated with co-expression or loss of E-cadherin expression, is seen in neoplastic transformation of oral and oesophageal squamous mucosa and in lesions representing early neoplastic transformation of glandular mucosa, such as aberrant crypt foci and metaplastic and adenomatous polyps. This same phenotype is seen in enterocytes adjacent to foci of ulceration in the intestine in colitis, including inflammatory bowel disease, and in colitis-associated dysplasia. In coeliac disease, reversible E-cadherin down-regulation correlates with the degree of villous atrophy, but in contrast with colitis, aberrant P-cadherin expression is not a feature. Aberrant epithelial P-cadherin expression is thus associated with a proliferative phenotype related to ulceration and neoplastic transformation in the gastrointestinal tract, which may confer a survival advantage on these cells, but the relative functional roles of P-cadherin and E-cadherin and the molecular mechanisms underlyingP-cadherin/catenin interactions have yet to be elucidated.

The incidence of both esophageal adenocarcinoma and Barrett’s esophagus, a premalignant condition predisposing to this cancer, is rising rapidly. There is growing evidence that both of these conditions are related to the reflux of acid and bile into the esophagus. This results in inflammation and cell damage which initiates a sequence of events termed the metaplasia-dysplasia-carcinoma sequence in which the squamous epithelium is replaced by columnar epithelium exhibiting increasing degrees of dysplasia and overt malignancy. This sequence of events is underpinned by changes in cell cycling, such as accumulation of p16 and p53 mutations and increased cyclin D1 activity. Progression along this pathway is characterized by changes in intercellular adhesion, in particular, loss of adenomatous polyposis coli, reduced cadherin expression and increased catenin phosphorylation resulting in its nuclear translocation. Herein, we detail these molecular defects and propose how they may interrelate in an ordered progression in the development of esophageal adenocarcinoma.

There are 5 to 6 levels of biomarker validation. Those for Barrett's esophagus are currently at level 3, despite small prospective studies. What is ideally required is a very large prospective assessment of biopsies in large cohorts, such as the ASPirin Esomeprazole Chemoprevention Trial (AspECT) and Barrett's Oesophagus Surveillance Study (BOSS) trials, so that unbiased and random selection of cases can be subjected to rigorous pathology and biomarker assessment (level 4). Only then can the predictive power of the data be exploited in a randomized intervention trial (level 5) whereby a series of biomarkers would trigger therapy. The real trouble is that this spot is currently occupied, satisfactorily according to some researchers, by conventional histological identification of high-grade dysplasia (HGD) as used in a recent randomized study of ablation in Barrett's esophagus (BE).