Barrett's Progression Research Articles

A personalized and dynamic risk estimation model: The new paradigm in Barrett's esophagus surveillance.

ObjectivesThe current surveillance strategy in Barrett’s esophagus (BE) uses only histological findings of the last endoscopy to assess neoplastic progression risk. As predictor values vary across endoscopies, single measurements may not be an accurate reflection. Our aim was to explore the value of using longitudinal evolutions (i.e. successive measurements) of histological findings (low-grade dysplasia (LGD)) and immunohistochemical biomarkers (p53 and SOX2) by investigating the association with Barrett’s progression.MethodsIn this proof-of-principle study of a longitudinal dynamic risk estimation model with a multicenter cohort design, 631 BE patients from 15 Dutch hospitals who were under surveillance were included. Longitudinal dynamic values of LGD, p53, and SOX2 were included in a multivariate joint model to estimate the risk of high-grade dysplasia (HGD)/esophageal adenocarcinoma (EAC).ResultsLongitudinal evolutions of aberrant expression of p53 (HR 1.26, p<0.01) and SOX2 (HR 1.43, p<0.01) were associated with an increased HGD/EAC risk. We also found weak evidence of an association with the longitudinal evolution of the presence of LGD (HR 1.02, p = 0.12). The performance of the model was good (AUC 0.80–0.88). Using this model, for each future BE patient the probability of aberrant expression of biomarkers based on multiple longitudinal observations can be estimated. This probability is translated in progression risk, expressed as HR.ConclusionsThis study provides solid ground to further explore a paradigm shift from currently recommended fixed intervals towards personalized surveillance, in which tailored risk estimations and corresponding surveillance intervals can be updated at every FU endoscopy for individual BE patients.

Challenges in Determining the Role of Microbiome Evolution in Barrett's Esophagus and Progression to Esophageal Adenocarcinoma.

Esophageal adenocarcinoma (EAC) claims the lives of half of patients within the first year of diagnosis, and its incidence has rapidly increased since the 1970s despite extensive research into etiological factors. The changes in the microbiome within the distal esophagus in modern populations may help explain the growth in cases that other common EAC risk factors together cannot fully explain. The precursor to EAC is Barrett’s esophagus (BE), a metaplasia adapted to a reflux-mediated microenvironment that can be challenging to diagnose in patients who do not undergo endoscopic screening. Non-invasive procedures to detect microbial communities in saliva, oral swabs and brushings from the distal esophagus allow us to characterize taxonomic differences in bacterial population abundances within patients with BE versus controls, and may provide an alternative means of BE detection. Unique microbial communities have been identified across healthy esophagus, BE, and various stages of progression to EAC, but studies determining dynamic changes in these communities, including migration from proximal stomach and oral cavity niches, and their potential causal role in cancer formation are lacking. Helicobacter pylori is negatively associated with EAC, and the absence of this species has been implicated in the evolution of chromosomal instability, a main driver of EAC, but joint analyses of microbiome and host genomes are needed. Acknowledging technical challenges, future studies on the prediction of microbial dynamics and evolution within BE and the progression to EAC will require larger esophageal microbiome datasets, improved bioinformatics pipelines, and specialized mathematical models for analysis.

Fundoplication is superior to medical therapy for Barrett's esophagus disease regression and progression: a systematic review and meta-analysis.

Fundoplication and medical management are current mainstays for management of Barrett's esophagus (BE), however our understanding of differences in outcomes between these two treatments is limited. The aim of this study was to perform a systematic review and meta-analysis to evaluate the efficacy of these interventions on BE disease regression and progression. A comprehensive search in MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library databases was performed on February 22, 2021. Inclusion criteria were studies with both medical and surgical management comparators, BE diagnosis prior to treatment, patients aged ≥ 18years, and studies with greater than five patients. Primary outcomes of interest included evaluating changes in histopathologic BE regression and disease progression between interventions. Meta-analysis was performed using a Mantel-Haenszel random-effects model (RevMan 5.4.1). A total of 7231 studies were retrieved after initial search with nine studies (1 randomized trial, 7 prospective cohorts, 1 retrospective cohort) meeting final inclusion criteria. Of included studies, 890 (65%) patients received medical management while 470 (35%) received surgical management. Medical management included proton pump inhibitors (n = 807, 91%; 6 studies), H2-receptor blockers (n = 40, 4% patients; 3 studies), and combination therapy (n = 43, 5%; 1 study). Nissen fundoplication was the most commonly performed type of fundoplication (n = 265, 93%). Median length of follow-up ranged from 1.5-7years. Meta-analysis revealed that fundoplication was associated with improved histopathologic regression of metaplasia/low-grade dysplasia (OR 4.38; 95% CI 2.28-8.42; p < 0.00001) and disease progression to dysplasia/adenocarcinoma (OR 0.34; 95% CI 0.12-0.96; p = 0.04) compared to medical therapy. Fundoplication is superior to medical therapy with regards to improved odds of histopathologic BE disease regression and disease progression. Additional randomized trials which directly compare medical management and surgical intervention are required to delineate the optimal delivery and timing of these interventions.

Immune determinants of Barrett's progression to esophageal adenocarcinoma.

Esophageal adenocarcinoma (EAC) develops from Barrett’s esophagus (BE), a chronic inflammatory state that can progress through a series of transformative dysplastic states before tumor development. While molecular and genetic changes of EAC tumors have been studied, immune microenvironment changes during Barrett’s progression to EAC remain poorly understood. In this study, we identify potential immunologic changes that can occur during BE-to-EAC progression. RNA sequencing (RNA-Seq) analysis on tissue samples from EAC patients undergoing surgical resection demonstrated that a subset of chemokines and cytokines, most notably IL6 and CXCL8, increased during BE progression to EAC. xCell deconvolution analysis investigating immune cell population changes demonstrated that the largest changes in expression during BE progression occurred in M2 macrophages, pro–B cells, and eosinophils. Multiplex immunohistochemical staining of tissue microarrays showed increased immune cell populations during Barrett’s progression to high-grade dysplasia. In contrast, EAC tumor sections were relatively immune poor, with a rise in PD-L1 expression and loss of CD8+ T cells. These data demonstrate that the EAC microenvironment is characterized by poor cytotoxic effector cell infiltration and increased immune inhibitory signaling. These findings suggest an immunosuppressive microenvironment, highlighting the need for further studies to explore immune modulatory therapy in EAC.

Role of submucosal glands in the development and progression of carcinoma in Barrett's oesophagus

Oesophageal submucosal glands secrete mucins and other chemicals that are believed to serve as protectants of the mucosal surface from luminal noxious agents, either ingested or refluxed. Changes in the type, distribution or number of submucosal glands may contribute to, or be associated with, the development of Barrett's oesophagus and progression to cancer. The aim of this study was to investigate the anatomical, morphological and immunohistochemical characteristics of submucosal glands in Barrett's oesophagus-associated neoplasia in 64 oesophageal resections for Barrett's oesophagus-associated adenocarcinoma and 32 squamous cell carcinomas (as a control group). Gland density was not significantly different between the oesophageal adenocarcinoma (0.91/cm) and squamous cell carcinoma (0.81/cm) groups (p=0.7). In the oesophageal adenocarcinoma group, glands underlying Barrett's oesophagus-associated neoplastic epithelium showed a significant decrease in the percentage of mucinous acini and a significant increase in the percentage of atrophic acini compared to glands underlying epithelium without dysplasia or carcinoma (74% vs 83%, p=0.03; and 24% vs 14%, p=0.01). There was also an increase in the percentage of glands with moderate to severe inflammation underlying neoplastic epithelium compared to glands underlying epithelium without dysplasia or carcinoma (53% vs 33%, p=0.001). None of these differences was seen in the squamous cell carcinoma group. The immunohistochemical characteristics of the different histological subtypes were also distinct. Atrophic and oncocytic acini were diffusely and strongly positive for CK7, SOX2, SOX9 and CK5/6 (a progenitor cell phenotype) while mucinous acini showed weak or moderate staining for those markers. Our results suggest that submucosal glands play a role in the progression of neoplasia, possibly by offering less protection to the mucosal surface of the oesophageal epithelium from chemical injury.

527 TissueCypher™ Barrett's Esophagus Assay for Risk Stratification of Barrett's Esophagus Patients With “Low Grade Crypt Dysplasia” on WATS3D® Brush

INTRODUCTION: Barrett's Esophagus (BE) and progression into esophageal adenocarcinoma (EA) is a major cause of cancer-related morbidity and mortality in the United States. Surveillance of patients with non-dysplastic BE has encountered a subset of specimens termed low grade crypt dysplasia (BE-LGCD) through use of Wide Area Trans-Epithelial Sampling (WATS) brush. The natural history of BE-LGCD is not currently known. To better characterize the risk of progression from LGCD to EA, we utilized a TissueCypher BE analysis (a validated BE risk progression tool) to produce a comprehensive risk prediction for development of high-grade dysplasia (HGD) or EA in patients with BE. METHODS: We sampled 17 patients with a history of BE made via Esophagogastroduodenoscopy (EGD) biopsy with WATS brush samples displaying “LGCD” between July 01,2017 to July 01, 2018. Pathology slides collected via standard of care screening EGDs were sent to an affiliate laboratory for the TissueCypher BE analysis. TissueCypher categorized the risk of progression as either low (Risk score 0-&lt; 5.5), Intermediate (5.5-&lt; 6.4), and High (Risk score &gt; 6.4) based on protein-based biomarkers. TissueCypher analysis generated an in-depth score analysis for risk of progression to EA. We used measures of central tendency to identify the risk of progression and studied identified risks of BE (BMI, smoking, age, gender, family history, GERD). We also used Regression Analysis and Kendall Tests to determine significance of these variables as well as their dependence on elevated risk. RESULTS: Of the 17 samples included, 5.8% represented female patients. The Mean age was 64.2 years. Mean risk of progression was overall low (Risk Score of 4.95, SD of 1.30). 100% of samples collected were from Caucasian patients. Increased segment length of BE, increased BMI, history of GERD or tobacco use, and family history of BE or EA did not correlate with increased risk of progression [Table 1]. BMI, smoking history, BE segment length, GERD history, as well as family history were not statistically dependent variables [Table 2]. CONCLUSION: Our data implies that BE-LGCD is not associated with increased risk of progression to EA. It mostly affects Caucasian males. Smoking, high BMI, segment length, history of GERD, and family history were not associated with increased risk of progression towards EA. Limitations to this study include a small sample size vs non-representative sample population. Future studies could identify progression of these patients.

The cyclical hit model: how paligenosis might establish the mutational landscape in Barrett's esophagus and esophageal adenocarcinoma.

In this review, we explore a paligenosis-based model to explain Barrett's esophagus development and progression: 'the cyclical hit model.' Genomic analyses have highlighted the high mutational burden of esophageal adenocarcinoma, Barrett's esophagus, and even normal esophageal epithelium. Somatic mutations in key genes including TP53 occur early in the neoplastic progression sequence of Barrett's esophagus, whereas chromosomal amplification resulting in oncogene activation occurs as a critical late event. Paligenosis is a shared injury response mechanism characterized by activation of autophagy, expression of progenitor markers, and increased mTORC signaling-induced cell-cycle reentry. In the setting of chronic injury/inflammation, cycles of paligenosis may allow accumulation of mutations until eventually the mutational burden, in concert perhaps with mutations in key driver oncogenes, finally alters the cell's ability to redifferentiate, leading to the emergence of a potential neoplastic clone. Under conditions of chronic gastroesophageal refluxate exposure, the normal esophageal squamous epithelium might undergo multiple cycles of paligenosis, allowing initially silent mutations to accumulate until key events impart mutant clones with an oncogenic survival advantage.

Does anti-reflux surgery disrupt the pathway of Barrett's esophagus progression to cancer?

In patients with Barrett's esophagus (BE), anti-reflux surgery aims to sustainable control reflux symptoms and heal reflux induced esophageal mucosal inflammation and prevent progression of BE to adenocarcinoma. There is growing evidence that beside gastric acid, bile salts in refluxed duodenal juice are responsible for the development and progression of BE. However, the pathogenesis of BE progression and the metaplasia-dysplasia-carcinoma sequence of the adenocarcinoma of the esophagus (EAC) is multifactorial and occurs over long natural time course. After anti-reflux surgery significant levels of regression from metaplastic Barrett's to non-metaplastic epithelium as well as from dysplastic to non-dysplastic BE have been observed and a randomized trial showed that sufficient surgical reflux control reduces the risk of Barrett's progression significantly when compared to medical treatment. Thus, large cohort studies show significant reduced risk of EAC in patients suffering from gastroesophageal reflux disease (GERD) with and without BE after anti-reflux surgery. Even after anti-reflux surgery the risk for EAC remains elevated in patients with BE and the right moment of intercepting the progressive nature of GERD has to be discussed in future. The paper also addresses the impact of anti-reflux surgery, endoscopic ablation and life style therapies for the management of GERD, BE and cancer prevention.

Tu1933 - Shifts in the Microbiome Associated with Barrett's Esophagus and Progression to Dysplasia and Adenocarcinoma

Tu1933 - Shifts in the Microbiome Associated with Barrett's Esophagus and Progression to Dysplasia and Adenocarcinoma

Potential Role of the Microbiome in Barrett's Esophagus and Esophageal Adenocarcinoma.

Esophageal adenocarcinoma and its precursor Barrett's esophagus have been rapidly increasing in incidence for half a century, for reasons not adequately explained by currently identified risk factors such as gastroesophageal reflux disease and obesity. The upper gastrointestinal microbiome may represent another potential cofactor. The distal esophagus has a distinct microbiome of predominantly oral-derived flora, which is altered in Barrett's esophagus and reflux esophagitis. Chronic low-grade inflammation or direct carcinogenesis from this altered microbiome may combine with known risk factors to promote Barrett's metaplasia and progression to adenocarcinoma.

Role of body composition and metabolic profile in Barrett's oesophagus and progression to cancer.

Background and aimsThe aim of this study was to evaluate the risk for Barrett’s oesophagus (BE) on the basis of body composition, metabolic pathways, adipokines and metabolic syndrome (MS), as well as their role in cancer progression.MethodsIn patients with and without BE at gastroscopy, data on MS, BMI, waist/hip ratio for abdominal obesity (AO) and body fat percentage by bioimpedance were obtained. Fasting plasma glucose, insulin, HbA1c, lipid, serum adiponectin and leptin levels were measured. The homoeostasis model assessment (HOMA-IR) was used to estimate insulin resistance. Histological findings for BE were correlated with the above parameters. Risk factors for BE identified using univariate analysis were entered into a multivariate logistic regression analysis.ResultsA total of 250 patients and 224 controls (F/M: 189/285, mean age 58.08±15.51 years) were enroled. In the BE and control groups, 39.6 versus 31.3% were overweight, 32 versus 22.8% were obese, 75.6 versus 51.3% had AO, and 28.1 versus 18.9% were metabolically obese, respectively. AO [odds ratio (OR) 3.08], increased body fat percentage (OR 2.29), and higher BMI (overweight: OR 2.04; obese: OR 2.26) were significantly associated with BE. A positive trend was found in Normal Weight Obese Syndrome (OR 1.69). MS was associated with BE (overweight: OR 3.05; obese: OR 5.2; AO: OR 8.08). Insulin levels (P=0.05) and HOMA-IR (P<0.001) were higher in BE. AO was the only independent risk factor associated with BE (OR 1.65; P=0.02) and high-grade dysplasia (OR 2.44) on multivariate analysis.ConclusionAO was strongly associated with BE and dysplasia. BE was associated with MS and higher insulin/HOMA-IR, suggesting the activation of specific metabolic pathways in patients with altered body composition.

Genetic Biomarkers of Barrett's Esophagus Susceptibility and Progression to Dysplasia and Cancer: A Systematic Review and Meta-Analysis.

Barrett’s esophagus (BE) is a common and important precursor lesion of esophageal adenocarcinoma (EAC). A third of patients with BE are asymptomatic, and our ability to predict the risk of progression of metaplasia to dysplasia and EAC (and therefore guide management) is limited. There is an urgent need for clinically useful biomarkers of susceptibility to both BE and risk of subsequent progression. This study aims to systematically identify, review, and meta-analyze genetic biomarkers reported to predict both. A systematic review of the PubMed and EMBASE databases was performed in May 2014. Study and evidence quality were appraised using the revised American Society of Clinical Oncology guidelines, and modified Recommendations for Tumor Marker Scores. Meta-analysis was performed for all markers assessed by more than one study. A total of 251 full-text articles were reviewed; 52 were included. A total of 33 germline markers of susceptibility were identified (level of evidence II–III); 17 were included. Five somatic markers of progression were identified; meta-analysis demonstrated significant associations for chromosomal instability (level of evidence II). One somatic marker of progression/relapse following photodynamic therapy was identified. However, a number of failings of methodology and reporting were identified. This is the first systematic review and meta-analysis to evaluate genetic biomarkers of BE susceptibility and risk of progression. While a number of limitations of study quality temper the utility of those markers identified, some—in particular, those identified by genome-wide association studies, and chromosomal instability for progression—appear plausible, although robust validation is required.Electronic supplementary materialThe online version of this article (doi:10.1007/s10620-015-3884-5) contains supplementary material, which is available to authorized users.

Oxidative DNA Damage in Barrett Mucosa: Correlation with Telomeric Dysfunction and p53 Mutation

Barrett esophagus develops in a scenario of chronic inflammation, linked to free radical formation and oxidative DNA damage. Eight-hydroxydeoxyguanosine, the main oxidative DNA adduct, is partially repaired by a glycosylase (OGG1) whose polymorphism is associated to a reduced repair capacity. Telomeres are particularly prone to oxidative damage, which leads to shortening and cell senescence, while elongation, by telomerase activity, is linked to cell immortalization and cancer. Limited data are available on this point with respect to Barrett esophagus. This study aimed to evaluate the link among 8-hydroxydeoxyguanosine, OGG1 polymorphism, telomerase activity, telomere length, and p53 mutation in Barrett progression. Forty consecutive patients with short- and long-segment Barrett esophagus and 20 controls with gastroesophageal reflux disease without Barrett esophagus were recruited. Analysis of biopsy samples was undertaken to study 8-hydroxydeoxyguanosine levels, OGG1 polymorphism, telomerase activity, and telomere length. Serum samples were obtained for p53 mutation. Controls had significantly lower levels of 8-hydroxydeoxyguanosine and telomerase activity, with normal telomere length and no p53 mutation. In short-segment Barrett esophagus, 8-hydroxydeoxyguanosine levels were higher and telomeres underwent significant shortening, with stimulation of telomerase activity but no p53 mutations. In long-segment Barrett esophagus, 8-hydroxydeoxyguanosine reached maximal levels, with telomere elongation, and 42 % of the patients showed p53 mutation. In Barrett patients, with disease progression, oxidative DNA damage accumulates, causing telomere instability, telomerase activation, and, in a late phase, mutations in the p53 gene, thus abrogating its activity as the checkpoint of proliferation and apoptosis, and facilitating progression to cancer.

Editorial: Optimization and Expansion of Predictive Models for Barrett's Esophagus and Esophageal Adenocarcinoma: Could a Life-Course Exposure History Be Beneficial?

Thrift et al. provide preliminary evidence that younger age of symptomatic gastroesophageal reflux disease exposure is associated with increased risk of Barrett's esophagus. If these findings are confirmed in other studies, the next logical steps are to test whether this, and other age-specific exposures, can help optimize predictive models of Barrett's esophagus and progression to esophageal adenocarcinoma. Expansion of these models to the general population and the greater Barrett's esophagus population, respectively, will be required for a screening and surveillance approach to be clinically successful and cost-effective.

Activity of the leukotriene pathway in Barrett’s metaplasia and oesophageal adenocarcinoma

Leukotriene (LT) B(4) is a lipid inflammatory mediator implicated in tumorigenesis in animal models of Barrett's oesophagitis, but little is known about the cysteinyl-leukotrienes (LTC(4), LTD(4), LTE(4)), which have distinct inflammatory and tumorigenic actions in other tissues. We recently showed that the terminal enzymes for the synthesis of both LT families are highly expressed in human oesophageal adenocarcinoma (OA) tissues. This study therefore examined the capacity of Barrett's metaplasia (BM) and OA tissues to synthesise LTs in vitro. Oesophageal biopsies from patients with BM (n=14), high-grade dysplasia (n=2), OA (n=11), and squamous control tissues (n=11) were cultured with calcium ionophore A32187 (2μM) for 60min. LTB(4) and cysteinyl-leukotrienes were extracted and measured by specific enzyme immunoassays. Levels of LTB(4) and cysteinyl-leukotrienes were 8.6-fold (P<0.01) and 2.4-fold (P<0.02) higher, respectively, in OA tissues than in squamous control tissues, but levels in BM tissues (n=14) were not altered. Production of the two LT families correlated across all tissue types (r=0.62, p<0.00005). Increased synthesis of LTB(4) and cysteinyl-leukotrienes has not previously been shown in human OA tissue and our results may indicate a role of these lipids in Barrett's disease progression.

P16 gene mutations in Barrett's esophagus in gastric metaplasia – intestinal metaplasia – dysplasia – adenocarcinoma sequence

Barrett's associated esophageal adenocarcinoma (ADC) is one of the malignancies of most rapidly increasing incidence. The aim of the study was to assess p16 tumor suppressor gene alterations in the ADC premalignant conditions. In the present study two p16 gene mutations (A148T and I49S) analysis with PCR- RFLP method have been performed in oesophageal biopsy specimen in 33 patients with Barrett's gastric metaplasia (GM), 27 - with Barrett's intestinal metaplasia (IM), 8 - with dysplasia and 11 - with ADC. We have detected the I49S mutation in 12% (4/33) patients with GM, 18% (5/27) with IM, 50% - with dysplasia (4/8) and in 27% (3/11) - with ADC. The A148T mutation were found in 3% (1/33) patients with GM, 22% (6/27) - IM, 25% (2/8) - dysplasia and 27% patients with ADC (3/11). The frequency of the A148S mutation was rising in GM - IM - dysplasia - ADC sequence and was significantly lower in GM compared to all other grades taken together (p=0.0256). The frequency of the I49S mutation was rising in GM - IM - dysplasia sequence, to drop in ADC cases. There were no significant differences in frequency of the I49S mutation between studied groups. These findings are consistent with the hypothesis on the role of the p16 mutations in early phase of Barrett's epithelium progression to ADC. The presence of p16 mutations in esophageal metaplastic columnar epithelium without goblet cells suggest that this pathology may have malignancy potential.

PWE-019 Mitochondrial instability is elevated in Barrett's oesophagus and dimethyloxalylglycine has a potential role in reversing this dysfunction

IntroductionDeoxycholic acid (DCA), a component of bile, has been associated with the development and progression of Barrett's oesophagus (BO). In addition, the “mutator-phenotype hypothesis” states benign cells with high rates...

The Association of Manganese Superoxide Dismutase Expression in Barrett's Esophageal Progression With MnTBAP and Curcumin Oil Therapy

The aim of this study was to investigate the relationship between reflux induced bile insult and MnSOD expression, as well as to examine therapies to preserve MnSOD expression. Additionally, we sought to examine the relationship between MnSOD protein expression and MnSOD enzymatic activity. MnSOD protein expression was determined by Western blot assay and enzymatic activity was determined by SOD assay. The enzymatic activity of the Het-1A and Bar-T cells were compared both before and after treatments. MnSOD expression in Het-1A cells was decreased after bile salt exposure. The cells that received MnTBAP or curcumin oil pretreatment showed increased MnSOD expression compared with control untreated cells. The Bar-T cells showed an increase in MnSOD expression after treatment with bile salts. The cells that were pretreated with MnTBAP displayed a larger increase in MnSOD expression compared with the cells that were not pretreated prior to bile salt exposure. The MnSOD activity was significantly different between the untreated cell lines (P = 0.01) and after treatment with bile salt (P = 0.03). Additionally, Bar-T cells had significantly less MnSOD activity than Het-1A cells after each of the pretreatments. We demonstrated preservation of MnSOD expression in Het-1A cells that were pretreated with antioxidants including MnTBAP, curcumin oil, and certain berry extracts. Additionally, we demonstrated that Bar-T cells have significantly less MnSOD activity than Het-1A cells. These finding have important implications for future studies regarding chemoprevention and the treatment of esophageal cancer.

Glutathione peroxidase 7 protects against oxidative DNA damage in oesophageal cells

ObjectiveExposure of the oesophageal mucosa to gastric acid and bile acids leads to the accumulation of reactive oxygen species (ROS), a known risk factor for Barrett's oesophagus and progression to...

Nitric oxide-mediated invasion in Barrett's high-grade dysplasia and adenocarcinoma

Nitric oxide (NO) has been shown to induce double strand DNA breaks in Barrett's oesophagus (BO) and in other cancers has a role in invasion. The specific aims of this study were to investigate whether NO can induce invasion in cells representative of different stages of Barrett's progression and to determine possible underlying mechanisms. Physiological concentrations of NO that mimic luminal production of NO from dietary sources enhanced invasion in cell lines from high-grade dysplasia (GihTERT) and oesophageal adenocarcinoma (FLO) but not a non-dysplastic Barrett's cell line (QhTERT). Real-time reverse transcription-polymerase chain reaction revealed that NO induced expression of matrix metalloproteinase (MMP)-1, -3, -7, -9 and -10 and tissue inhibitor of metalloproteinase (TIMP)-1, -2 and -3 in these cell lines. Furthermore, ex vivo treatment of Barrett's biopsy samples with NO induced increases in MMP-1 and TIMP-1 expression, suggesting that NO enhances invasion through deregulating MMP and TIMP expression in epithelial cells. In keeping with these findings, microarray analysis and immunohistochemistry performed on biopsy samples showed enhanced expression of MMP-1, -3, -7 and -10 and TIMP-1 in the progression from non-dysplastic BO to adenocarcinoma, although this could not be directly attributed to the effect of NO. Thus, NO may play a role in Barrett's carcinogenesis through deregulating MMP and TIMP expression to enhance invasive potential.