A proportion of Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) displays familial aggregation, known as familial Barrett’s esophagus (FBE). Pedigrees and characteristics of EAC in these families have been previously described.
We aimed to evaluate endoscopic and clinical characteristics of Barrett’s esophagus in FBE.
A cohort of 979 BE patients were retrospectively evaluated for FBE, defined as having a first-degree relative with BE or esophageal cancer, confirmed when possible by interview. FBE and sporadic BE were compared regarding demographic, clinical, and endoscopic characteristics. Potential FBE probands were contacted and interviewed to obtain full family pedigrees.
Of 603 BE probands (61.6% of total cohort) with a documented family history, 35 (5.8%) had FBE. There was no difference between FBE and non-FBE probands with regard to BE length (median: 3 cm, IQR 2-5 vs. 3 cm, IQR 1-6 cm, respectively; p = 0.78) or hiatal hernia size (p = 0.90). FBE probands were younger (mean, 58.4 vs. 63.8; p = 0.02) and had a significant association with less-advanced neoplasia (adjusted OR 0.41, 95% CI 0.19–0.90). There was no obvious association between FBE and other malignancies.
There were no differences in endoscopic characteristics between FBE and non-FBE probands. While FBE patients were younger and had less-advanced neoplasia, we speculate that these findings may have been the result of more aggressive screening due to the family history. Further studies are warranted to determine whether familial clustering is due to genetic predisposition to development of BE or to risk of neoplastic progression.
Barrett’s esophagus; Epidemiology; Genetic predisposition to disease
Genetic influences may be discerned in families that have multiple affected members and may manifest as an earlier age of cancer diagnosis. In this study we determine whether cancers develop at an earlier age in multiplex Familial Barrett’s Esophagus (FBE) kindreds, defined by 3 or more members affected by Barrett’s esophagus (BE) or esophageal adenocarcinoma (EAC).
Information on BE/EAC risk factors and family history was collected from probands at eight tertiary care academic hospitals. Age of cancer diagnosis and other risk factors were compared between non-familial (no affected relatives), duplex (two affected relatives), and multiplex (three or more affected relatives) FBE kindreds.
The study included 830 non-familial, 274 duplex and 41 multiplex FBE kindreds with 274, 133 and 43 EAC and 566, 288 and 103 BE cases, respectively. Multivariable mixed models adjusting for familial correlations showed that multiplex kindreds were associated with a younger age of cancer diagnosis (p = 0.0186). Median age of cancer diagnosis was significantly younger in multiplex compared to duplex and non-familial kindreds (57 vs. 62 vs. 63 yrs, respectively, p = 0.0448). Mean body mass index (BMI) was significantly lower in multiplex kindreds (p = 0.0033) as was smoking (p < 0.0001), and reported regurgitation (p = 0.0014).
Members of multiplex FBE kindreds develop EAC at an earlier age compared to non-familial EAC cases. Multiplex kindreds do not have a higher proportion of common risk factors for EAC, suggesting that this aggregation might be related to a genetic factor.
These findings indicate that efforts to identify susceptibility genes for BE and EAC will need to focus on multiplex kindreds.
Esophageal adenocarcinoma; Barrett’s esophagus; genetics; family history
BACKGROUND AND AIMS
Adenocarcinomas of the esophagus and adenocarcinomas of the gastroesophageal junction are postulated to be complex genetic diseases. Combined influences of environmental factors and genetic susceptibility likely influence the age at which these cancers develop. The aim of this study was to determine whether familiality and other recognized risk factors are associated with the development of these cancers at an earlier age.
A structured validated questionnaire was utilized to collect self reported data on gastro-esophageal reflux symptoms, risk factors for Barrett’s esophagus (BE) and family history, including age of cancer diagnosis in affected relatives from probands with BE, adenocarcinoma of the esophagus, or adenocarcinoma of the gastro-esophageal junction, at five tertiary care academic hospitals. Medical records of all relatives reported to be affected were requested from hospitals providing this cancer care to confirm family histories. Familiality of BE/cancer, obesity (defined as body mass index > 30), gastro-esophageal reflux symptoms, and other risk factors were assessed for association with a young age of cancer diagnosis.
A total of 356, 216 non-familial and 140 familial, cancers were studied. The study population consisted of 292 (82%) men and 64 (18%) women. Mean age of cancer diagnosis was no different comparing familial and non-familial cancers, 62.6 yrs vs. 61.9 yrs, p = 0.70. There were also no significant differences in symptoms of gastroesophageal reflux, body mass index, race, gender, and smoking history between familial and non-familial cancers. Mean age of cancer diagnosis was significantly younger comparing those who were obese one year prior to diagnosis with those who were non-obese, mean age 58.99 yrs vs. 63.6 yrs, p = 0.008. Multivariable modeling of age at cancer diagnosis showed that obesity 1 year before diagnosis was associated with a younger age of cancer diagnosis (p=0.005) after adjustment for heartburn and regurgitation duration.
Obesity is associated with the development of esophageal and gastro-esophageal junctional adenocarcinomas at an earlier age. Familial cancers arise at the same age as non-familial cancers and have a similar risk factor profile.
Since the early 1970s, a dramatic change has occurred in the epidemiology of esophageal malignancy in both North America and Europe: the incidence of adenocarcinomas of the lower esophagus and esophagogastric junction is increasing. Several lifestyle factors are implicated in this change, including gastroesophageal reflux disease (gerd). Primary esophageal adenocarcinomas are thought to arise from Barrett esophagus, an acquired condition in which the normal esophageal squamous epithelium is replaced by a specialized metaplastic columnar-cell-lined epithelium.
Today, gerd is recognized as an important risk factor in Barrett esophagus. Progression of Barrett esophagus to invasive adenocarcinoma is reflected histologically by the metaplasia–dysplasia–carcinoma sequence. Although several molecular alterations associated with progression of Barrett esophagus to invasive adenocarcinoma have been identified, relatively few will ultimately have clinical application. Currently, the histologic finding of high-grade dysplasia remains the most reliable predictor of progression to invasive esophageal adenocarcinoma. However other promising molecular biomarkers include aneuploidy; 17p loss of heterozygosity, which implicates the TP53 tumour suppressor gene; cyclin D1 protein overexpression; and p16 alterations. It is anticipated that models incorporating combinations of objective scores of sociodemographic and lifestyle risk factors (that is, age, sex, body mass index), severity of gerd, endoscopic and histologic findings, and a panel of biomarkers will be developed to better identify patients with Barrett esophagus at increased risk for malignant progression, leading to more rational endoscopic surveillance and screening programs.
Barrett esophagus; esophageal adenocarcinoma; molecular pathogenesis; biomarkers
Barrett’s esophagus, a pre-malignant condition that can lead to esophageal adenocarcinoma, is characterized by histological changes in the normal squamous epithelium of the esophagus. Numerous molecular changes occur during the multistage conversion of Barrett’s metaplasia to dysplasia and frank adenocarcinoma. Epigenetic changes, especially changes in DNA methylation are widespread during this process. Aberrant DNA methylation has been shown to occur at promoters of tumor suppressor genes, adhesion molecules and DNA repair genes during Barrett’s esophagus. These epigenetic alterations can be used as molecular biomarkers for risk stratification and early detection of esophageal adenocarcinoma. We also show that genome wide analysis of methylation surprisingly reveals that global hypomethylation and not hypermethylation is the dominant change during Barrett’s metaplasia. The transformation of Barrett’s esophagus to frank adenocarcinoma is in turn characterized by much smaller wave of selective promoter hypermethylation. These studies reveal many novel, potential targets for new therapies and illustrate the utility of incorporating these epigenetic changes as biomarkers during endoscopic surveillance interval for patients with Barrett’s esophagus.
Barrett’s esophagus; DNA methylation; esophageal adenocarcinoma; global hypomethylation
Barrett’s esophagus is a condition in which the normal stratified squamous epithelium of the distal esophagus is replaced by intestinal metaplasia. For more than three decades the prevailing clinical paradigm has been that Barrett’s esophagus is a complication of symptomatic reflux disease that predisposes to esophageal adenocarcinoma, yet no clinical strategy for cancer prevention or early detection based on this paradigm has been proven to reduce esophageal adenocarcinoma mortality in a randomized clinical trial in part because only about 5-10% of individuals with Barrett’s esophagus develop esophageal adenocarcinoma. Recent research indicates that Barrett’s metaplasia is an adaptation for mucosal defense in response to chronic reflux in most individuals. The risk of progressing to esophageal adenocarcinoma is determined by development of genomic instability and dynamic clonal evolution in the distal esophagus modulated by host and environmental risk and protective factors, including inherited genotype. The challenge in Barrett’s esophagus lies in integrating knowledge about genomic instability and clonal evolution into clinical management to increase the lifespans and quality of life of individuals with this condition.
Background & Aims
Barrett’s esophagus is a precursor of esophageal adenocarcinoma. DNA microarrays that enable a genome-wide assessment of gene expression enhance the identification of specific genes as well as gene expression patterns that are expressed by Barrett’s esophagus and adenocarcinoma compared to normal tissues. Barrett's esophagus length has also been identified as a risk factor for progression to adenocarcinoma, but whether there are intrinsic biological differences between short and long-segment Barrett's esophagus can be explored with microarrays.
Gene expression profiles for endoscopically obtained biopsies of Barrett’s esophagus or esophageal adenocarcinoma, and associated normal esophagus and duodenum were identified for 17 patients using DNA microarrays. Unsupervised and supervised approaches for data analysis defined similarities and differences between the tissues as well as correlations with clinical phenotypes.
Each tissue displays a unique expression profile that distinguishes it from each other. Barrett’s esophagus and esophageal adenocarcinoma express a unique set of stromal genes that is distinct from normal tissues, but similar to other cancers. Adenocarcinoma also showed lower and higher expression for many genes compared to Barrett's esophagus. No difference in gene expression was found between short and long-segment Barrett's esophagus.
The genome-wide assessment provided by current DNA microarrays reveals many candidate genes and patterns not previously identified. Stromal gene expression in Barrett’s esophagus and adenocarcinoma are similar, indicating that these changes precede neoplasia.
In Barrett’s esophagus, the stratified squamous epithelium lining the esophagus is replaced by specialized intestinal-type columnar epithelium. The prevalence of Barrett’s esophagus has ranged from 0.9% to 4.5%. The rate of progression from Barrett’s esophagus to esophageal adenocarcinoma is 0.5% per patient-year. Proton-pump inhibitors are the mainstay of symptom control in Barrett’s patients. Nondysplastic Barrett’s and Barrett’s with low-grade dysplasia (LGD) are typically managed by periodic surveillance. Radiofrequency ablation is being evaluated as a modality for managing nondysplastic Barrett’s and Barrett’s with LGD. The options for the management of Barrett’s patients with high-grade dysplasia (HGD) include endoscopic therapy, surgery, and intensive surveillance until biopsy reveals adenocarcinoma. Endoscopic therapy involves endoscopic mucosal resection (EMR) and ablation. More aggressive techniques such as endoscopic submucosal dissection and larger segment endoscopic mucosal resection are under study. In this review, we discuss the diagnosis and management of Barrett’s esophagus. The recommendations from the major gastroenterologic societies and the current and investigational endoscopic modalities for the management of Barrett’s esophagus with and without dysplasia are reviewed.
Barrett esophagus; endoscopic surgical procedures; esophageal neoplasms
Barrett’s esophagus is a metaplasia of the distal esophagus that is the only recognized precursor of esophageal adenocarcinoma. Despite a characteristic histology, the pathogenesis of Barrett’s has remained obscure. A recent paper from the laboratories of Wa Xian and Frank McKeon presents evidence for a novel cell of origin of Barrett’s. Their work is based on studies of mice engineered to lack the squamous epithelial stem cell survival factor p63. These mice develop a metaplasia of the proximal stomach and esophagus that harbors substantial histological and molecular features of Barrett’s. The metaplasia appears to form from embryonic progenitor cells that normally persists post-natally only at the squamo-columnar junction. Moreover, in their model, the metaplasia is initiated not by mutation but by reduced competition between these cells and squamous epithelial cells.
Barrett's esophagus; epithelial stem cell; esophageal adenocarcinoma; esophageal cancer; metaplasia; p63; progenitor cell
The major risk factors for esophageal adenocarcinoma are gastroesophageal reflux disease (GERD) and Barrett esophagus, a squamous-to-columnar cell metaplasia that predisposes to malignancy. Adenocarcinomas in Barrett esophagus are thought to arise through a sequence of growth-promoting, genetic alterations that accumulate until the cells have acquired the physiologic hallmarks of cancer proposed by Hanahan and Weinberg. Moreover, GERD and Barrett esophagus are associated with chronic esophagitis, and inflammation is a well known risk factor for cancer formation. The cell that gives rise to Barrett metaplasia is not known. It has been proposed that the metaplasia may arise from a change in the differentiation pattern of stem cells that either reside in the esophagus or are recruited to the esophagus from the bone marrow. Alternatively, it is possible that Barrett metaplasia develops through the conversion of one differentiated cell type into another. Regardless of the cell of origin, Barrett metaplasia ultimately must be sustained by stem cells, which might be identified by intestinal stem cell markers. An emerging concept in tumor biology is that cancer stem cells are responsible for sustaining tumor growth. If Barrett cancers develop from Barrett stem cells, then a therapy targeted at those stem cells might prevent esophageal adenocarcinoma. This report reviews the risk factors for Barrett esophagus and esophageal adenocarcinoma, the mechanisms by which genetic alterations might contribute to carcinogenesis in Barrett esophagus, and the role of stem cells in the development of Barrett metaplasia and adenocarcinoma.
Barrett esophagus; Esophageal adenocarcinoma; Metaplasia; Stem Cells
Esophageal intestinal metaplasia, also known as Barrett’s esophagus, is the replacement of the normal epithelium with one that resembles the intestine morphologically. Generally, this includes intestinal mucin-secreting goblet cells. Barrett’s esophagus is an important risk factor for adenocarcinoma development. In vitro models for Barrett’s esophagus have not, to date, focused on the induction of goblet cells in Barrett’s epithelium.
To explore the contribution of Math1/Atoh1 in the induction of Barrett’s esophagus and intestinal mucin-secreting goblet cells from normal human esophageal epithelium.
We explored the level and pattern of Math1/Atoh1 mRNA and protein expression in human Barrett’s esophagus. Then, using retroviral-mediated gene expression, we induced Math1 mRNA and protein expression in a human esophageal keratinocyte cell line. We evaluated the effects of this ectopic Math1 expression upon cell proliferation and gene expression patterns in cells cultured under 2-dimensional and 3-dimensional tissue engineering conditions.
Math1/Atoh1 mRNA and protein are detected in human Barrett’s esophagus specimens, but the mRNA levels vary considerable. In the keratinocyte expression studies, we observed that Math1/Atoh1 ectopic expression significantly reduced cell proliferation and altered cell morphology. Moreover, Math1/Atoh1 expression is associated with a more intestinalized gene expression pattern that is distinct from prior published studies using other intestinal transcription factors. Most significantly we observe the induction of the Barrett’s esophagus markers Mucin-2 and Keratin-20 with Math1/Atoh1 expression.
We conclude that ectopic Math1/Atoh1 expression makes unique contributions to the intestinalization of esophageal epithelium in Barrett’s esophagus.
Barrett’s esophagus; Math1/Atoh1; Keratin-20; metaplasia; Mucin-2; organotypic culture
Previous studies that showed an association between smoking and adenocarcinomas of the esophagus and esophagogastric junction were limited in their ability to assess differences by tumor site, sex, dose–response, and duration of cigarette smoking cessation.
We used primary data from 10 population-based case–control studies and two cohort studies from the Barrett’s Esophagus and Esophageal Adenocarcinoma Consortium. Analyses were restricted to white non-Hispanic men and women. Patients were classified as having esophageal adenocarcinoma (n = 1540), esophagogastric junctional adenocarcinoma (n = 1450), or a combination of both (all adenocarcinoma; n = 2990). Control subjects (n = 9453) were population based. Associations between pack-years of cigarette smoking and risks of adenocarcinomas were assessed, as well as their potential modification by sex and duration of smoking cessation. Study-specific odds ratios (ORs) estimated using multivariable logistic regression models, adjusted for age, sex, body mass index, education, and gastroesophageal reflux, were pooled using a meta-analytic methodology to generate summary odds ratios. All statistical tests were two-sided.
The summary odds ratios demonstrated strong associations between cigarette smoking and esophageal adenocarcinoma (OR = 1.96, 95% confidence interval [CI] = 1.64 to 2.34), esophagogastric junctional adenocarcinoma (OR = 2.18, 95% CI = 1.84 to 2.58), and all adenocarcinoma (OR = 2.08, 95% CI = 1.83 to 2.37). In addition, there was a strong dose–response association between pack-years of cigarette smoking and each outcome (P < .001). Compared with current smokers, longer smoking cessation was associated with a decreased risk of all adenocarcinoma after adjusting for pack-years (<10 years of smoking cessation: OR = 0.82, 95% CI = 0.60 to 1.13; and ≥10 years of smoking cessation: OR = 0.71, 95% CI = 0.56 to 0.89). Sex-specific summary odds ratios were similar.
Cigarette smoking is associated with increased risks of adenocarcinomas of the esophagus and esophagogastric junction in white men and women; compared with current smoking, smoking cessation was associated with reduced risks.
Esophageal adenocarcinoma (EAC) arises in the backdrop of reflux-induced metaplastic phenomenon known as Barrett esophagus. The prognosis of advanced EAC is dismal, and there is an urgent need for identifying molecular targets for therapy. Serial Analysis of Gene Expression (SAGE) was performed on metachronous mucosal biopsies from a patient who underwent progression to EAC during endoscopic surveillance. SAGE confirmed significant upregulation of Axl “tags” during the multistep progression of Barrett esophagus to EAC. In a cohort of 92 surgically resected EACs, Axl overexpression was associated with shortened median survival on both univariate (p < 0.004) and multivariate (p < 0.036) analysis. Genetic knockdown of Axl receptor tyrosine kinase (RTK) function was enabled in two EAC lines (OE33 and JH-EsoAd1) using lentiviral short hairpin RNA (shRNA). Genetic knockdown of Axl in EAC cell lines inhibited invasion, migration and in vivo engraftment, which was accompanied by downregulation in the activity of the Ral GTPase proteins (RalA and RalB). Restoration of Ral activation rescued the transformed phenotype of EAC cell lines, suggesting a novel effector mechanism for Axl in cancer cells. Pharmacological inhibition of Axl was enabled using a small molecule antagonist, R428 (Rigel Pharmaceuticals). Pharmacological inhibition of Axl with R428 in EAC cell lines significantly reduced anchorageindependent growth, invasion and migration. Blockade of Axl function abrogated phosphorylation of ERBB2 (Her-2/neu) at the Tyr877 residue, indicative of receptor crosstalk. Axl RTK is an adverse prognostic factor in EAC. The availability of small molecule inhibitors of Axl function provides a tractable strategy for molecular therapy of established EAC.
Barrett esophagus; Axl; Ral GTP; SAGE
Esophageal adenocarcinoma (EAC) arises in the backdrop of reflux-induced metaplastic phenomenon known as Barrett esophagus. The prognosis of advanced EAC is dismal, and there is an urgent need for identifying molecular targets for therapy. Serial Analysis of Gene Expression (SAGE) was performed on metachronous mucosal biopsies from a patient who underwent progression to EAC during endoscopic surveillance. SAGE confirmed significant upregulation of Axl “tags” during the multistep progression of Barrett esophagus to EAC. In a cohort of 92 surgically resected EACs, Axl overexpression was associated with shortened median survival on both univariate (p < 0.004) and multivariate (p < 0.036) analysis. Genetic knockdown of Axl receptor tyrosine kinase (RTK) function was enabled in two EAC lines (OE33 and JH-EsoAd1) using lentiviral short hairpin RNA (shRNA). Genetic knockdown of Axl in EAC cell lines inhibited invasion, migration and in vivo engraftment, which was accompanied by downregulation in the activity of the Ral GTPase proteins (RalA and RalB). Restoration of Ral activation rescued the transformed phenotype of EAC cell lines, suggesting a novel effector mechanism for Axl in cancer cells. Pharmacological inhibition of Axl was enabled using a small molecule antagonist, R428 (Rigel Pharmaceuticals). Pharmacological inhibition of Axl with R428 in EAC cell lines significantly reduced anchorage-independent growth, invasion and migration. Blockade of Axl function abrogated phosphorylation of ERBB2 (Her-2/neu) at the Tyr877 residue, indicative of receptor crosstalk. Axl RTK is an adverse prognostic factor in EAC. The availability of small molecule inhibitors of Axl function provides a tractable strategy for molecular therapy of established EAC.
Barrett esophagus; Axl; Ral GTP; SAGE
Barrett’s Esophagus is considered to be a precursor to adenocarcinoma and the information on VDR expression in normal and Barrett’s esophagus is significantly lacking. In this study, we examined the expression of VDR in the lower esophagus and gastric cardia of normal and Barrett’s esophagus by immunofluorescence. Columnar mucosa but not squamous mucosa at the gastroesophageal junction showed positive immunofluorescence to VDR. Submucosal glands and ducts deep to the normal squamous mucosa stained positive for VDR and localized in the cytoplasm and perinuclear regions with no nuclear staining. Interestingly, the Barrett’s mucosa stained strongly positive for VDR. Glandular structures in the mucosal layer were far less abundant in the Barrett’s mucosa than in the normal gastric mucosa. As a result, fewer structures deep to the Barrett’s epithelial layer stained positive for VDR when compared to normal gastric mucosa. These findings suggest that in normal esophagus VDR expression is restricted to columnar epithelium and glandular structures. Furthermore, strong VDR expression in Barrett’s mucosa may indicate an increased sensitivity of this tissue to endogenous or therapeutic effects of Vitamin D.
Barrett’s esophagus; Epithelium; Gastroesophageal junction; Vitamin D; Vitamin D receptor
Barrett’s esophagus is a precursor of esophageal adenocarcinoma, both of which are associated with gastroesophageal reflux disease (GERD). Screening GERD patients for Barrett’s esophagus has been suggested, but it is not known which patients should be screened, and at what age.
To determine the age-specific yield of endoscopy for Barrett’s esophagus stratified by gender and indication for endoscopy.
Retrospective cross-sectional study.
National Endoscopic Database of the Clinical Outcomes Research Initiative (CORI).
155,641 patients undergoing their first endoscopy at one of the CORI sites for clinical indication.
Main Outcome Measurements
Age-specific yield of Barrett’s esophagus.
Among white men with GERD, the yield for Barrett’s esophagus rises steeply from early adulthood (2.1% in 3rd decade of life) to middle adulthood (9.3% in 6th decade), and then plateaus (difference for 8th decade minus 6th decade = −1.1%, 95% confidence interval [CI] = −3.9%, +1.7%). There is no difference in yield of Barrett’s esophagus between middle-aged white women with GERD and white men without GERD (difference = −0.46%, 95% CI = −1.23%, +0.31%).
Possible bias by selection for endoscopy, and potential for misclassification of GERD status.
The yield of upper endoscopy for diagnosis of Barrett’s esophagus increases rapidly among white men with GERD until approximately age 50, then reaches a plateau. White women with GERD are at no increased risk compared to white men without GERD.
Barrett’s esophagus; Epidemiology
The past few years have brought new advances in our understanding of the molecular mechanisms underlying the development of Barrett’s esophagus and esophageal adenocarcinoma. Although knowledge of the genetic basis for these conditions has not yet translated into clinically useful biomarkers, the current pace of biomedical discovery holds endless possibilities for molecular medicine to improve the diagnosis and management of patients with these conditions. This article provides a useful conceptual basis for understanding the molecular events involved in the making of Barrett’s metaplasia and in its neoplastic progression and provides a rationale for evaluating studies on the application of molecular medicine to the diagnosis and management of patients with Barrett’s esophagus and esophageal adenocarcinoma.
Barrett’s esophagus; metaplasia; esophageal adenocarcinoma
The role of non-acidic reflux contents on the pathophysiology of Barrett’s Esophagus remains poorly understood. We hypothesized that esophageal squamous epithelium differs from Barrett’s columnar epithelium in response to bile salts with respect to subsequent changes in the cell surface expression of CD95 (Fas/Apo-1) and sensitivity to CD95-mediated apoptosis.
Immortalized esophageal squamous cells (HET-1A) and Barrett’s Esophagus cells (BAR-T), and esophageal adenocarcinoma cells (Flo-1) were treated with toxic and non-toxic bile salts at concentrations observed in gastroesophageal refluxate. CD95 cell-surface expression and apoptotic response to activating anti-CD95 antibody treatment was determined by FACScan analysis.
Bile salt exposure resulted in a dose-dependent increase in CD95 cell-surface expression in HET-1A cells, but not BAR-T or Flo-1 cells. This response occurred rapidly, within a time-frame inconsistent with de novo protein synthesis and was blocked by protein kinase C (PKC) inhibition. Surprisingly, PKC inhibition in Flo-1 cells resulted in an increase in CD95 cell surface expression. Following bile salt exposure, a corresponding increase in the induction of CD95-mediated apoptosis was observed in HET-1A cells; PKC inhibition sensitized Flo-1 cells to apoptosis.
Our findings suggest that esophageal squamous cells are sensitized to CD95-mediated apoptosis following bile salt exposure. This response differs from that in columnar epithelial cells, and may offer a potential mechanism of selection pressure that contributes to the pathophysiology of Barrett’s Esophagus.
Barrett’s Esophagus; Gastroesophageal Reflux Disease; Esophageal Adenocarcinoma
Barrett's esophagus predisposes to esophageal adenocarcinoma. However, the value of endoscopic surveillance in Barrett's esophagus has been debated because of the low incidence of esophageal adenocarcinoma in Barrett's esophagus. Moreover, high inter-observer and sampling-dependent variation in the histologic staging of dysplasia make clinical risk assessment problematic. In this study, we developed a 3-tiered risk stratification strategy, based on systematically selected epigenetic and clinical parameters, to improve Barrett's esophagus surveillance efficiency.
Methods and Findings
We defined high-grade dysplasia as endpoint of progression, and Barrett's esophagus progressor patients as Barrett's esophagus patients with either no dysplasia or low-grade dysplasia who later developed high-grade dysplasia or esophageal adenocarcinoma. We analyzed 4 epigenetic and 3 clinical parameters in 118 Barrett's esophagus tissues obtained from 35 progressor and 27 non-progressor Barrett's esophagus patients from Baltimore Veterans Affairs Maryland Health Care Systems and Mayo Clinic. Based on 2-year and 4-year prediction models using linear discriminant analysis (area under the receiver-operator characteristic (ROC) curve: 0.8386 and 0.7910, respectively), Barrett's esophagus specimens were stratified into high-risk (HR), intermediate-risk (IR), or low-risk (LR) groups. This 3-tiered stratification method retained both the high specificity of the 2-year model and the high sensitivity of the 4-year model. Progression-free survivals differed significantly among the 3 risk groups, with p = 0.0022 (HR vs. IR) and p<0.0001 (HR or IR vs. LR). Incremental value analyses demonstrated that the number of methylated genes contributed most influentially to prediction accuracy.
This 3-tiered risk stratification strategy has the potential to exert a profound impact on Barrett's esophagus surveillance accuracy and efficiency.
Prediction of progression to cancer in patients with Barrett’s esophagus is difficult using current techniques. We determined whether DNA promoter hypermethylation of genes frequently methylated in esophageal adenocarcinoma (p16 and APC) could be used as predictors of progression in Barrett’s esophagus.
We first performed a cross-sectional study to evaluate the prevalence of gene hypermethylation in biopsies from patients with normal esophagus (n=17), Barrett’s esophagus (n=102), and adenocarcinoma (n=42). We then performed a nested case-control study comparing gene hypermethylation in Barrett’s esophagus patients who progressed from baseline pathology to high-grade dysplasia or cancer (n=7) versus patients who did not progress (n=50).
None of the patients with normal esophagus had p16 or APC hypermethylation. Hypermethylation was prevalent in Barrett’s esophagus without dysplasia or low-grade dysplasia (p16=31% and APC=50%; p<0.01) and high-grade dysplasia or adenocarcinoma (p16=54% and APC=68%; p<0.001) compared to normal esophagus (not detected). Patients who progressed from baseline pathology to high-grade dysplasia or cancer had higher prevalence of hypermethylation in their initial esophagus biopsies compared to those who did not progress for both p16 (100% vs. 33%; p=0.008) and APC (86% vs. 40%; p=0.02). Hypermethylation of both p16 and APC was a strong predictor of subsequent progression to cancer during a mean follow-up time of 4.1 years (adjusted OR [95% CI]=14.97 [1.73,inf], p=0.01). Among patients who were negative for both p16 and APC hypermethylation, none progressed from baseline pathology to high-grade dysplasia or cancer.
Hypermethylation of both p16 and APC strongly predicts progression to high-grade dysplasia or cancer in patients with Barrett’s esophagus. Absence of p16 and APC hypermethylation is associated with a benign course.
Barrett's esophagus, a risk factor for esophageal adenocarcinoma, is associated with reflux disease. The aim of this study was to assess the expression of bile acid receptors in the esophagus (normal, esophagitis, Barrett's esophagus and adenocarcinoma) and to investigate their possible function.
the expression of the bile acid receptors FXR and VDR in esophageal biopsies from patients with a normal mucosa, esophagitis, Barrett's esophagus or adenocarcinoma (n = 6 per group) and in cell lines derived from Barrett's esophagus and esophageal adenocarcinoma, was assessed by real time Q-PCR and immunohistochemistry. The effect of guggulsterone, an antagonist of bile acid receptors, on apoptosis of Barrett's esophagus-derived cells was assessed morphologically, by flow cytometry and by measuring caspase 3 activity.
The expression of FXR was increased in esophagitis, Barrett's esophagus and adenocarcinoma compared to normal mucosa by a mean of 44, 84 and 16, respectively. Immunohistochemistry showed a weak expression in normal esophagus, a strong focal reactivity in Barrett's esophagus, and was negative in adenocarcinoma. VDR expression did not significantly differ between groups. In cell cultures, the expression of FXR was high in Barrett's esophagus-derived cells and almost undetectable in adenocarcinoma-derived cells, whereas VDR expression in these cell lines was not significantly different. In vitro treatment with guggulsterone was associated with a significant increase in the percentage of apoptotic cells and of the caspase 3 activity.
the bile acid receptor FXR is significantly overexpressed in Barrett's esophagus compared to normal mucosa, esophagitis and esophageal adenocarcinoma. The induction of apoptosis by guggulsterone in a Barrett's esophagus-derived cell line suggests that FXR may contribute to the regulation of apoptosis.
Barrett esophageal cancer has the fastest growing incidence of any cancer in Western countries. In Asian countries, most cases of esophageal cancer consist of squamous cell carcinomas, not adenocarcinomas. Recently, however, the increase in the number of Barrett esophagus cases with subsequent Barrett cancer has become worrisome in Asian countries, as the number of patients with gastro-esophageal reflux disease has been increasing in these countries. In this review, recent reports regarding Barrett esophagus in Asian countries have been collected and this problem is discussed from various perspectives. In Asia, long-segment Barrett esophagus is much less prevalent than in Western countries, whereas short-segment Barrett esophagus is frequently found. In epidemiologic studies, evaluation of the prevalence of Barrett esophagus is limited by poor interob-server diagnostic agreement. Standard criteria for the endoscopic diagnosis of Barrett esophagus in Asian patients, especially of the short-segment type, should be established as soon as possible. A high prevalence of hiatal hernia and a decreasing prevalence of Helico-bacter pylori infection may increase the number of Barrett esophagus cases and subsequent Barrett cancer in Asian countries in the near future. Therefore, a strategy for the clinical management of Barrett esophagus in Asian countries should be devised.
Barrett esophagus; Asian population; endoscopic diagnosis; Helicobacter pylori infection
Barrett’s esophagus is a metaplastic alteration of the normal esophageal epithelium that is detected on endoscopic examination and pathologically confirmed by the presence of intestinal metaplasia on biopsy. Its major significance is as a predisposing factor for esophageal adenocarcinoma, which carries a high mortality rate and a rapidly growing incidence in the United States. Detection of Barrett’s esophagus allows for endoscopic surveillance in order to detect the potential development of dysplasia and early cancer before symptoms develop, and thereby significantly increases treatment options and may lower mortality from esophageal adenocarcinoma. Much current work in the field is aimed at reducing the risk of progression from Barrett’s esophagus to cancer, and in the identification of biomarkers that may predict progression towards cancer. Barrett’s esophagus is present in 10%–20% of patients with gastroesophageal reflux disease (GERD) and has also been detected in patients who deny classic GERD symptoms and are undergoing endoscopy for other indications. We used an evidence-based approach to describe treatment options for patients with Barrett’s esophagus.
Barrett’s esophagus; esophageal adenocarcinoma; evidence-based approach; endoscopic surveillance
Barrett's esophagus is a premalignant condition of esophageal adenocarcinoma. Inducible nitric oxide synthase (iNOS) is induced by cytokines and can generate locally high concentrations of nitric oxide (NO), whose metabolites can mediate genotoxicity and influence multistage carcinogenesis by causing DNA damage. Therefore, we evaluated the immunolocalization and expression of iNOS in surgically induced rat Barrett's esophagus. Esophagoduodenal anastomosis was performed in rats for inducing reflux of duodenal contents. Rats were killed at postoperative 10, 20, 30 and 40 weeks. We examined histologic changes and iNOS expression in esophagus by immunohistochemistry and reverse transcription-polymerase chain reaction. Eighty six percent of experimental rats showed Barrett's esophagus above esophagoduodenal junction. iNOS immunoreactivity was clearly observed in the epithelial cells of Barrett's esophagus, predominantly at the apical surface of epithelial cells. Cytoplasmic staining was also seen only in atypical Barrett's esophagus. iNOS mRNA was detected only in the lower esophagus of experimental group. In conclusion, this study suggests that iNOS has some roles on Barrett's esophagus formation.
Barrett Esophagus; inducible nitric oxide synthase
Cigarette smoking is associated with esophageal adenocarcinoma (EAC), esophagogastric junctional adenocarcinoma (EGJA) and esophageal squamous cell carcinoma (ESCC), and alcohol consumption with ESCC. However, no analyses have examined how delivery rate modifies the strength of odds ratio (OR) trends with total exposure, i.e., the impact on the OR for a fixed total exposure of high exposure rate for short duration compared with low exposure rate for long duration.
The authors pooled data from 12 case-control studies from the Barrett’s Esophagus and Esophageal Adenocarcinoma Consortium (BEACON), including 1,242 (EAC), 1,263 (EGJA) and 954 (ESCC) cases and 7,053 controls, modeled joint ORs for cumulative exposure and exposure rate for cigarette smoking and alcohol consumption, and evaluated effect modification by sex, body mass index (BMI), age and self-reported acid reflux.
For smoking, all sites exhibited inverse delivery rate effects, whereby ORs with pack-years increased, but trends weakened with increasing cigarettes/day. None of the examined factors modified associations, except for ESCC where younger ages at diagnosis enhanced smoking effects (P<0.01). For EAC and EGJA, ORs with drink-years exhibited inverse associations in <5 drinks/day consumers and no association in heavier consumers. For ESCC, ORs with drink-years increased, with trends strengthening with greater drinks/day. There was no significant effect modification, except for EAC and EGJA where acid reflux mitigated the inverse associations (P=0.02). For ESCC, younger ages at diagnosis enhanced drinking-related ORs (P<0.01).
Patterns of ORs by pack-years and drink-years, delivery rate effects and effect modifiers revealed common as well as distinct etiologic elements for these diseases.
alcohol drinking; risk model; smoking