Barrett's esophagus: an update

Electrical stimulation to increase lower esophageal sphincter pressure after POEM

INTRODUCTION

Postoperative reflux remains to be a challenge for patients with achalasia undergoing Heller myotomy. Similarly, per-oral endoscopic myotomy (POEM) is gaining rapid acceptance but the impossibility of adding a fundoplication is questioned as the main pitfall to control reflux. Electrical stimulation of the lower esophageal sphincter (LES) has emerged as a new alternative for the treatment of reflux disease. The objective of this study was to evaluate the potential benefits of combining electrical stimulation with endoscopic esophageal myotomy to prevent post procedural reflux.

METHODS

Five pigs were subjected to POEM. After myotomy was completed, two electrical leads were implanted at the LES level and electrical stimulation was applied with the Endostim system with a regimen of 215 μs (5 mA amplitude), at 20 Hz for 25 min. LES pressures were recorded with manometry at pre and post-myotomy and after LES stimulation.

RESULTS

Myotomy was completed successfully in all cases. Mean pre-myotomy LES pressure was 35.99 ± 8.08 mmHg. After myotomy, the LES pressure significantly dropped to 10.60 ± 3.24 mmHg (p = 0.03). Subsequent to LES-EST, LES pressure significantly increased to 21.74 ± 4.65 mmHg (p = 0.01).

CONCLUSIONS

The findings of this study show that LES-EST in healthy animals increases LES pressure after POEM procedure, and could be useful tool to minimize gastroesophageal reflux.

Reflux composition influences the level of NF-κB activation and upstream kinase preference in oesophageal adenocarcinoma cells

Oesophageal adenocarcinoma (OA) incidence is rising and prognosis is poor. Understanding the molecular basis of this malignancy is key to finding new prevention and treatment strategies. Gastroesophageal reflux disease is the primary cause of OA, usually managed with acid suppression therapy. However, this often does little to control carcinogenic bile acid reflux. The transcription factor nuclear factor kappa B (NF-κB) plays a key role in the pathogenesis of OA and its activity is associated with a poor response to chemotherapy, making it an attractive therapeutic target. We sought to decipher the role of different bile acids in NF-κB activation in oesophageal cell lines using short, physiologically relevant exposure times. The effect of an acidic or neutral extracellular pH was investigated concurrently, to mimic in vivo conditions associated with or without acid suppression. We found that some bile acids activated NF-κB to a greater extent when combined with acid, whereas others did so in its absence, at neutral pH. The precise composition of an individual's reflux, coupled with whether they are taking acid suppressants may therefore dictate the extent of NF-κB activation in the oesophagus, and hence the likelihood of histological progression and chemotherapy success. Regardless of pH, the kinase inhibitor of κB kinase was pivotal in mediating reflux induced NF-κB activation. Its importance was confirmed further as its increased activation was associated with histological progression in patient samples. We identified further kinases important in acid or bile induced NF-κB signalling in oesophageal cells, which may provide suitable targets for therapeutic intervention.

Family history of cancer and gastroesophageal disorders and risk of esophageal and gastric adenocarcinomas: a case-control study

Background

There is a paucity of data on familial risk of developing esophageal adenocarcinoma, gastric cardia adenocarcinoma and distal gastric adenocarcinoma from population-based studies.

Methods

A population-based case–control study of newly diagnosed gastroesophageal adenocarcinoma was conducted in Los Angeles County. This analysis included data of case-patients whom we were able to interview directly (147 patients with esophageal adenocarcinoma, 182 with gastric cardia adenocarcinoma, and 285 with distal gastric adenocarcinoma) and 1,309 control participants. Multivariate polytomous logistic regression was used to estimate odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the three cancer types.

Results

Risk of esophageal adenocarcinoma was positively associated with a family history of prostate cancer (OR = 2.84; 95% CI = 1.50-5.36) and a family history of hiatal hernia (OR = 2.04; 95% CI = 1.12-3.71). Risk of gastric cardia adenocarcinoma was strongly associated with a family history of esophageal cancer (OR = 5.18; 95% CI = 1.23-21.79) and a family history of hiatal hernia (OR = 2.31; 95% CI = 1.37-3.91). Risk of distal gastric adenocarcinoma was positively associated with a family history of gastric cancer (OR = 2.15; 95% CI = 1.18-3.91), particularly early-onset (before age 50) gastric cancer (OR = 2.82; 95% CI = 1.11-7.15).

Conclusions

This study provides evidence that family history of hiatal hernia is a risk factor for esophageal adenocarcinoma and gastric cardia adenocarcinoma and that cancer in specific sites is associated with risk of esophageal adenocarcinoma, gastric cardia adenocarcinoma, and distal gastric adenocarcinoma. It is important to determine the extent to which shared environmental and genetic factors explain these familial associations.

COX-derived prostanoid pathways in gastrointestinal cancer development and progression: novel targets for prevention and intervention

Arachidonic acid metabolism through cyclooxygenase (COX) pathways leads to the generation of biologically active eicosanoids. Eicosanoid expression levels vary during development and progression of gastrointestinal (GI) malignancies. COX-2 is the major COX-isoform responsible for G.I. cancer development/progression. COX-2 expression increases during progression from a normal to cancerous state. Evidence from observational studies has demonstrated that chronic NSAID use reduces the risk of cancer development, while both incidence and risk of death due to G.I. cancers were significantly reduced by daily aspirin intake. A number of randomized controlled trials (APC trial, Prevention of Sporadic Adenomatous Polyps trial, APPROVe trial) have also shown a significant protective effect in patients receiving selective COX-2 inhibitors. However, chronic use of selective COX-2 inhibitors at high doses was associated with increased cardiovascular risk, while NSAIDs have also been associated with increased risk. More recently, downstream effectors of COX-signaling have been investigated in cancer development/progression. PGE(2), which binds to both EP and PPAR receptors, is the major prostanoid implicated in the carcinogenesis of G.I. cancers. The role of TXA(2) in G.I. cancers has also been examined, although further studies are required to uncover its role in carcinogenesis. Other prostanoids investigated include PGD(2) and its metabolite 15d-PGJ2, PGF(1α) and PGI(2). Targeting these prostanoids in G.I. cancers has the promise of avoiding cardiovascular toxicity associated with chronic selective COX-2 inhibition, while maintaining anti-tumor reactivity. A progressive sequence from normal to pre-malignant to a malignant state has been identified in G.I. cancers. In this review, we will discuss the role of the COX-derived prostanoids in G.I. cancer development and progression. Targeting these downstream prostanoids for chemoprevention and/or treatment of G.I. cancers will also be discussed. Finally, we will highlight the latest pre-clinical technologies as well as avenues for future investigation in this highly topical research field.

Comparison of six immunohistochemical markers for the histologic diagnosis of neoplasia in Barrett's esophagus

In esophageal neoplasms, the histopathologic differentiation between Barrett's esophagus with or without intraepithelial neoplasia and adenocarcinoma is often challenging. Immunohistochemistry might help to differentiate between these lesions. The expression of CDX2, LI-cadherin, mucin 2 (MUC2), blood group 8 (BG8, Lewis(y)), claudin-2, and villin was investigated in normal gastroesophageal (n = 23) and in Barrett's (n = 17) mucosa, in low-grade (n = 12) and high-grade (n = 9) intraepithelial neoplasia (IEN) as well as in esophageal adenocarcinoma (n = 16), using immunohistochemistry. For CDX2 and LI-cadherin, the immunoreactivity score was highest in IEN while for MUC2, BG8, and villin, it dropped gradually from Barrett's via IEN to adenocarcinoma, and expression of Claudin-2 was only weak and focal in all lesions. The expression of MUC2 and LI-cadherin differed significantly between all examined lesions except between low-grade and high-grade IEN. MUC2 and LI-cadherin are useful immunohistochemical markers for the differentiation between normal glandular mucosa, Barrett's mucosa, IEN, and invasive carcinoma of the esophagus; however, none of the examined markers was helpful for the differentiation between low-grade and high-grade IEN.

CDX2 and LI-cadherin expression in esophageal mucosa: use of both markers can facilitate the histologic diagnosis of Barrett's esophagus and carcinoma

BACKGROUND

Barrett's mucosa is a risk factor for esophageal adenocarcinoma and should be detected at an early stage. CDX2 and liver-intestine (LI)-cadherin are intestine-specific markers. Aberrant CDX2 expression has been demonstrated in Barrett's metaplasia, esophagitis, and intestinal metaplasia of the stomach.

METHODS

The relationship between CDX2 and LI-cadherin expression was investigated in normal gastroesophageal (n = 24) and in Barrett's (n = 20) mucosa, in low-grade (n = 15) and high-grade (n = 13) intraepithelial neoplasia (IEN) as well as in esophageal adenocarcinoma (n = 16), using immunohistochemistry.

RESULTS

Nuclear positivity for CDX2 coupled with membranous expression of LI-cadherin was observed in about 70% of the epithelial cells of Barrett's mucosa. The intensity of staining and the percentage of positive cells increased within the sequential steps of low-grade to high-grade IEN, whereas the normal cylindric epithelium lacked the expression of both. In adenocarcinoma, the expression of LI-cadherin and CDX2 was significantly weaker or absent.

CONCLUSIONS

CDX2 and LI-cadherin are sensitive markers of intestinal metaplasia with or without dysplasia in the upper gastrointestinal tract. Both can be helpful for the early histologic diagnosis of Barrett's esophagus and its subsequent lesions; however, they do not significantly discern between different grades of dysplasia.

The role of photodynamic therapy in the esophagus

Photodynamic therapy (PDT) is a drug and device therapy using photosensitizer drugs activated by laser light for mucosal ablation. Porfimer sodium PDT has been used extensively with proven long-term efficacy and durability for the ablation of Barrett esophagus and high-grade dysplasia. and early esophageal adenocarcinoma. However, continued use is hampered by an associated stricture risk and prolonged photosensitivity (4-6 weeks). Promising single-center European studies using other forms of PDT, such as aminolevulinic acid PDT, have not been replicated elsewhere, limiting the widespread use of other forms of PDT. Future use of PDT in esophageal disease depends on the development of improved dosimetry and patient selection to optimize treatment outcomes, while minimizing adverse events and complications.

Barrett's esophagus: can biomarkers predict progression to malignancy?

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma. It is characterized histologically by a specialized intestinal metaplasia that replaces the squamous epithelium of the distal esophagus, and is associated with chronic gastroesophageal reflux disease and obesity. Similar to the adenoma-carcinoma sequence of colorectal carcinomas, esophageal adenocarcinoma develops through progression from BE to low- and high-grade dysplasia, then to adenocarcinoma with accumulation of genetic and epigenetic abnormalities. The exact malignancy potential of BE is uncertain. Dysplasia is the most predictive marker for risk of esophageal adenocarcinoma, whereas endoscopic and histological diagnoses are still the gold standard for surveillance of patients with BE. However, both are limited, either by sampling errors in biopsies or by differences in histological interpretation. Several studies have identified candidate biomarkers that may have predictive value and may serve as additional factors for the risk assessment of esophageal adenocarcinoma. This review discusses the role of biomarkers in the progression from BE to adenocarcinoma, focusing on clinical and molecular markers.

The usefulness of chromoendoscopy with methylene blue in Barrett's metaplasia and early esophageal carcinoma

BACKGROUND

Barrett's esophagus is a condition that is premalignant for adenocarcinoma of the esophagus and the esophagogastric junction. Early detection of Barrett's metaplasia and dysplasia is very important to decrease the mortality and morbidity from esophageal adenocarcinoma cancer. This study aimed to evaluate the effectiveness of methylene blue-targeted biopsies in the differential diagnosis of intestinal metaplasia, dysplasia, and superficial esophageal carcinoma.

METHODS

A total of 109 patients (43 women and 66 men; average age, 62.32 +/- 10.61 years; range, 33-82 years) were enrolled for the study. Four groups were designed before endoscopic examinations. The patients for these groups were selected at the conventional endoscopy, and then chromoendoscopy was performed. The esophagus was stained with methylene blue, after which six biopsies were taken from stained and unstained areas.

RESULTS

Conventional and chromoendoscopic assessments were compared with histopathologic examination. The sensitivity of chromoendoscopy for Barrett's epithelium was superior to that of conventional endoscopy (p < 0.05). However, there was no statistical difference between the two methods in the diagnosis of esophagitis or esophageal carcinoma (p > 0.05). Stained biopsies were superior to unstained biopsies in terms of sensitivity for Barrett's epithelium and esophageal carcinoma (p < 0.001).

CONCLUSION

Chromoendoscopy is useful for delineating Barrett's epithelium and for indicating the correct location for securing biopsies where dysplasia or early esophageal cancer is suspected.

Cyclooxygenase-2 inhibitors demonstrate anti-proliferative effects in oesophageal cancer cells by prostaglandin E(2)-independent mechanisms

The incidence of oesophageal cancer (OC) has risen in recent decades, with survival rates remaining poor despite surgical treatment and adjuvant chemotherapy. Studies have reported cyclooxygenase-2 (COX-2) overexpression in OC and current evidence suggests NSAIDs have major potential for chemoprevention through COX-2 inhibition. However, several reports have questioned the specificity of these inhibitors, suggesting they may act through mechanisms other than COX-2. We evaluated the effects of specific COX-2 inhibitors, NS-398 and nimesulide, on cell lines of both histological types of OC. COX-2 protein expression varied in the cell lines and corresponded with levels of prostaglandin E(2) (PGE(2)) production. Following treatment with low concentrations of NS-398 (0.1 microM), PGE(2) production was reduced dramatically, indicating inhibition of COX-2 activity. Examination of cellular morphology, caspase-3 activity and mitochondrial membrane integrity found no major induction of apoptotic cell death at concentrations below 100 microM. Tumour cell proliferation was significantly reduced at high concentrations (50-100 microM) of both inhibitors over 6 days. Cellular responses were more evident in NS-398-treated adenocarcinoma cells. However, concentrations required to inhibit proliferation were up to 1000-fold higher than those needed to inhibit enzyme activity. Addition of exogenous PGE(2) to NS-398-treated adenocarcinoma cells failed to reverse the inhibitory effects, indicating PG and COX-2 independence. It remains possible that in vivo COX-2 is the primary target, as enzyme inhibition can be achieved at low concentrations, however, inhibition of proliferation is not the primary mechanism of their anti-tumour activity.

Barrett's esophagus at a tertiary care center: association of age on incidence and prevalence of dysplasia and adenocarcinoma

OBJECTIVES

Barrett's esophagus (BE) is traditionally thought of as a disease of middle-aged Caucasian men. Little is known about BE in younger patients. We sought to assess the effect of age on features of BE including the prevalence and incidence of dysplasia and carcinoma.

METHODS

All patients enrolled into the Cleveland Clinic BE registry from 1979 to 2002 were studied. Age, ethnicity, number of endoscopies, hiatal hernia size, length of Barrett's segment, prevalence and incidence of dysplasia, and cancer were compared between patients > or = 50 yr old and < 50 yr old.

RESULTS

There were 837 patients in the registry (638 > or = 50 yr, 199 < 50 yr). Hiatal hernia size was larger in patients > or = 50 yr than in those < 50 yr (median 4.0 cm, interquartile range 2.0-5.0 cm vs 3.0, 2.0-4.0 cm; p < 0.01). Otherwise, there were no significant differences among other features in the patient population. There were 225 patients with dysplasia or cancer (195 > or = 50 yr and 30 < 50 yr; p < 0.01). Of this group, 176 were prevalent cases (159 > or = 50 yr and 17 < 50 yr) and 49 were incident cases (36 > or = 50 yr and 13 < 50 yr). The odds of those > or = 50 yr being a prevalent case of high-grade dysplasia or cancer was five times the odds of those < 50 yr (p < 0.01). The incidence of dysplasia or cancer was similar in both age groups.

CONCLUSIONS

Our study supports emerging data that approximately 25% of BE patients are less than 50 yr of age. While older patients had a higher prevalence of dysplasia or adenocarcinoma, the incidence of dysplasia and adenocarcinoma is similar in both age groups. Future screening strategies for BE should recognize these important findings.

Trends in incidence rates of oesophagus and gastric cancer in Italy by subsite and histology, 1986-1997

OBJECTIVE

Population-based studies in Western countries suggest that the incidence of oesophageal adenocarcinoma (OA) and gastric cardia adenocarcinoma (GCA) is increasing, whereas the incidence of distal gastric carcinoma and oesophageal squamous cell carcinoma (OSCC) is declining. This is the first population-based study carried out in a southern European region to evaluate the time trends in incidence rates of oesophageal and gastric tumours according to subsite and histology over the period 1986-1997.

METHODS

Cancer cases were drawn from seven registries of the Italian Network of Cancer Registries, which covers approximately 9% of the Italian population (annual average 5 027 944). Time trends in age and sex-standardized incidence rates were reported. Estimated annual percentage changes (EAPC) and related 95% confidence intervals (CI) were estimated by modelling age, sex, subsite and morphology-specific incidence rates through Poisson log-linear regression, and whenever necessary negative-binomial regression. Overall, 25 895 gastric and 2497 oesophageal carcinomas were examined.

RESULTS

On the whole, an increasing trend was observed for OA plus GCA. The increase was statistically significant in younger women (<60 years: EAPC 3.7; 95% CI 0.2; 7.3) and in older men (>75 years: EAPC 4.0; 95% CI 1.2; 6.9). Similar trends were also observed in proximal gastric cancer (GCA plus fundus). A decline in the stomach subfundus incidence was observed in both sexes and in each age group. OSCC decreased significantly in men (EAPC-2.6; 95% CI-4.1;-0.9).

CONCLUSIONS

It is plausible that the different tendencies in oesophageal and proximal gastric cancer in men and women are attributable to heterogeneous distributions of risk factors by sex or age.

Influence of acid and bile acid on ERK activity, PPARγ expression and cell proliferation in normal human esophageal epithelial cells

AIM: To observe the effects of acid and bile acid exposure on cell proliferation and the expression of extracellular signal-regulated protein kinase (ERK) and peroxisome proliferator-activated receptor γ (PPARγ) in normal human esophageal epithelial cells in vitro.

METHODS: In vitro cultured normal human esophageal epithelial cells were exposed to acidic media (pH 4.0 - 6.5), media containing different bile acid (250 μmol/L), media containing acid and bile acid, respectively. Cell proliferation was assessed using MTT and flow cytometry. The expressions of phosphorylated ERK_1/2 and PPARγ protein were determined by the immunoblotting technique.

RESULTS: Acid-exposed (3 min) esophageal cells exhibited a significant increase in proliferation ratio, S phase of the cell cycle (P < 0.05) and the level of phosphorylated ERK_1/2 protein. When the acid-exposure period exceeded 6 min, we observed a decrease in proliferation ratio and S phase of the cell cycle, with an increased apoptosis ratio (P < 0.05). Bile acid exposure (3-12 min) also produced an increase in proliferation ratio, S phase of the cell cycle (P < 0.05) and phosphorylated ERK_1/2 expression. On the contrary, deoxycholic acid (DCA) exposure (> 20 min) decreased proliferation ratio. Compared with bile acid exposure (pH 7.4), bile acid exposure (pH 6.5, 4) significantly decreased proliferation ratio (P < 0.05). There was no expression of PPARγ in normal human esophageal epithelial cells.

CONCLUSION: The rapid stimuli of acid or bile acid increase proliferation in normal human esophageal epithelial cells by activating the ERK pathway.

Endoprevention of esophageal cancer: endoscopic ablation of Barrett's metaplasia and dysplasia

This review describes the use of endoscopic therapy for the treatment of Barrett's disease and the prevention of esophageal carcinoma, predominantly a disease of older white men. While the term endoprevention may be novel, gastroenterologists have been using endoscopic techniques to prevent colon cancer for decades. For the endoprevention of Barrett's carcinoma, the regulatory approval for the use of porfimer sodium photodynamic therapy was an important milestone, as this treatment has been proven to safely ablate Barrett's glandular epithelium, including high-grade dysplasia, and significantly decrease the risk for the development of invasive cancer in several single-center studies, a prospective multicenter randomized controlled study using expert centralized histopathology analysis and long-term single-center results. Newer methods of mucosal ablation, such as the radiofrequency balloon, have been developed for the treatment of patients with Barrett's metaplasia or dysplasia. These newly developed techniques are able to treat large fields of glandular epithelium in a short treatment procedure using safe, effective, durable methods for the complete ablation of Barrett's metaplasia and low-grade dysplasia. These techniques may finally allow the interventional gastrointestinal endoscopist to prevent the development of esophageal carcinoma, just as colonoscopy with polypectomy has prevented colon cancer. However, it will be critically important to document the safety, durability and efficacy of these devices. Ultimately, the impact of successful Barrett's ablation on the incidence of Barrett's carcinoma, and the need for postablation surveillance endoscopy must be determined.

Molecular biology of Barrett's cancer

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 (Barrett's-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.

Photodynamic therapy for Barrett's esophagus with high-grade dysplasia

This article describes advances in photodynamic therapy for patients with Barrett's esophagus and high-grade dysplasia-an important, minimally invasive treatment option proven to safely and durably ablate Barrett's dysplasia and prevent carcinoma while preserving the gastroesophageal junction.

Expression of CDX2 and MUC2 in Barrett's mucosa

Barrett's mucosa is a risk factor for esophageal adenocarcinoma and should be detected at an early stage. It is defined by the presence of columnar epithelium with goblet cells in the lower esophagus, but histologic diagnosis can be uncertain in the absence of distinct goblet cells. We investigated 55 biopsies from 48 patients with endoscopically plain Barrett's esophagus and performed immunohistochemistry for CDX2 and MUC2. In addition, alcian blue (pH 2,5)/PAS staining was done. In histologically unequivocal Barrett's mucosa, nuclear expression of CDX2 in goblet cells and many columnar cells, as well as cytoplasmic positivity for MUC2 in goblet cells, could be observed. Alcian blue (pH 2,5)/PAS stained acidic mucins in goblet cells and in some non-goblet columnar cells. In six cases, no definite Barrett's mucosa was present, and no expression of MUC2 could be observed. In these biopsies, there was granular cytoplasmic and/or focal nuclear staining for CDX2 in non-goblet columnar epithelial cells, indicating their intestinal differentiation. We suggest that this peculiar mucosa is the precursor of unequivocal Barrett's mucosa and would designate it early Barrett's mucosa. Alcian blue for acidic mucins is inconsistent in this epithelium and does not reliably indicate early intestinal differentiation.

Endoscopic mucosal resection for high-grade dysplasia and intramucosal carcinoma in Barrett’s esophagus: An Italian experience

AIM: To evaluate endoscopic mucosal resection (EMR) in patients with high-grade dysplasia (HGD) and/or intramucosal cancer (IMC) in Barrett’s esophagus (BE).

METHODS: Between June 2000 and December 2003, 39 consecutive patients with HGD (35) and/or IMC (4) underwent EMR. BE >30 mm was present in 27 patients. In three patients with short segment BE (25.0%), HGD was detected in a normal appearing BE. Lesions had a mean diameter of 14.8±10.3 mm. Mucosal resection was carried out using the cap method.

RESULTS: The average size of resections was 19.7±9.4×14.6±8.2 mm. Histopathologic assessment post-resection revealed 5 low-grade dysplasia (LGD) (12.8%), 27 HGD (69.2%), 2 IMC (5.1%), and 5 SMC (-12.8%). EMR changed the pre-treatment diagnosis in 10 patients (25.6%). Three patients with SMC underwent surgery. Histology of the surgical specimen revealed 1 T0N0 and 2 T1N0 lesions. The remaining two patients were cancer free at 32.5 and 45.6 mo, respectively. A metachronous lesion was detected after 25 mo in one patient with HGD. Intra-procedural bleeding, controlled at endoscopy, occurred in four patients (10.3%). After a median follow-up of 34.9 mo, all patients remained in remission.

CONCLUSION: In the medium term, EMR is effective and safe to treat HGD and/or IMC within BE and is a valuable staging method. It could become an alternative to surgery.

Histochemical studies on intestinal metaplasia adjacent to gastric cardia adenocarcinoma in subjects at high-incidence area in Henan, north China

AIM: To characterize the histochemical type and pattern of intestinal metaplasia (IM) adjacent to gastric cardia adenocarcinoma (GCA) and distal gastric cancer (GC) in Linzhou, Henan Province, China.

METHODS: Alcian-blue-periodic acid Schiff and high iron diamine-Alcian blue histochemical methods were performed on 142 cases of IM, including 49 cases of GCA and 93 cases of GC. All the patients were from Linzhou, Henan Province, China, the highest incidence area for both GCA and squamous cell carcinoma. Radio- or chemotherapy was not applied to these patients before surgery.

RESULTS: The detection rate of IM in tissues adjacent to GCA tissues was 44.9%, which was significantly lower than that in GC tissues (80.64%, P < 0.01). The rates of both incomplete small intestinal and colonic IM types identified by histochemistry in GCA tissues (31.82% and 63.64%, respectively) were significantly higher than those in GC (5.33% and 21.33%, respectively, P < 0.01).

CONCLUSION: IM in GCA and GC should be considered as a separate entity. Further research is needed to evaluate whether neoplastic progression of IM is related to its mucin profile in GCA.

Tissue inhibitor of metalloproteinase-3 (TIMP-3) gene is methylated in the development of esophageal adenocarcinoma: loss of expression correlates with poor prognosis

Amongst involvement in diverse physiological and pathological processes, TIMP-3 may have an important role in tumour development, growth and metastasis by interaction with metalloproteases in the extracellular matrix. We studied the role and prognostic effect of TIMP-3 in esophageal adenocarcinoma (EADC). TIMP-3 gene methylation and TIMP-3 mRNA expression were analysed in 5 esophageal cell lines and 24 resected EADCs. TIMP-3 protein expression was examined in the 5 cell lines and 79 resected EADCs with known clinicopathological features. TIMP-3 methylation signal was only detected in the OE33 EADC cell line. In tissues, 0% of case-matched normal, 72% of BE and 90% of EADC were positive for methylation. TIMP-3 mRNA was detected in all the cell lines and normal, metaplastic and tumour tissues. TIMP-3 protein was localised to the cytoplasm in cell lines and tissues. Demethylating treatment of OE33 increased protein expression. At the invading edge of tumours, protein staining was equal to, or reduced, compared to normal tissues. Reduction of protein expression was associated with disease stage (p = 0.046) and poor patient survival (OR 2.1, 95% CI 1.2-3.5, p = 0.007). Mean survival time was halved in patients with reduced tumour TIMP-3 expression, from 49 to 24 months. These studies have demonstrated association between methylation of the TIMP-3 gene and BE and EADC. Reduced expression of TIMP-3 protein in EADC is associated with increased tumour invasiveness and reduced patient survival.

Present status of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

GOALS

Review recent developments in Barrett's dysplasia including regulatory approval of porfimer sodium photodynamic therapy.

BACKGROUND

Barrett's esophagus is thought to be the result of long-standing gastroesophageal reflux disease and is known to be the most important risk factor for the development of esophageal adenocarcinoma. The natural history of Barrett's esophagus is not well known, but the annual incidence of invasive adenocarcinoma is estimated to be 0.5% (reported range, 0.2%-2.0%). This represents an increased risk for esophageal cancer of 30 to 60 times higher than normal subjects. As for colorectal cancer, malignant degeneration is Barrett's esophagus is thought to occur through a continuum of histologic stages: metaplasia, dysplasia and neoplasia. Barrett's high-grade dysplasia (formerly referred to as carcinoma in situ) is the histologic stage of disease that immediately precedes the development of invasive carcinoma.

CONCLUSIONS

Previously, Barrett's high-grade dysplasia patients were routinely referred for esophageal resection surgery based upon the assumption of inevitable progression to cancer, the high rate of undiagnosed synchronous cancers, and few treatment alternatives. Important developments in Barrett's high-grade dysplasia include recent publications regarding the natural history of Barrett's high-grade dysplasia and the regulatory approval for endoscopic ablation therapy using porfimer sodium photodynamic therapy (Photofrin PDT).

Bioadhesive Dosage Forms for Esophageal Drug Delivery

The esophagus as a site for drug delivery has been much overlooked in comparison to the remainder of the gastrointestinal tract. The low permeability and transient nature of the esophagus means that it is unsuitable for delivery of drugs for systemic action. However, esophageal disorders including fungal infection, cancers, motility dysfunction, and damage due to gastric reflux may be treated using locally acting agents that offer benefits of reduced dosage and decreased side effects. Bioadhesive dosage forms that adhere to the esophageal mucosa and prolong contact have been investigated to improve the efficacy of locally acting agents. The rationale for local esophageal drug delivery and its limitations, the factors that determine adhesion to this organ, and the experimental models used in esophageal drug delivery research are reviewed.

MUC1 and MUC2 in pancreatic neoplasia

MUCs are glycoproteins with various roles in homeostasis and carcinogenesis. Among other actions, MUC1 may inhibit cell-cell and cell-stroma interactions and function as a signal transducer, participating in cancer progression. In contrast, MUC2 is normally found only in goblet cells, where it contributes to the protective barrier function of these cells. Recently, a tumour suppressor role has been demonstrated for MUC2, and both MUC1 and MUC2 appear to have important roles in pancreatic neoplasia. MUC1 appears to be a marker of aggressive phenotype and may facilitate the vascular spread of carcinoma cells. In contrast, MUC2 is rarely detectable in aggressive pancreatic tumours, but is commonly expressed in intraductal papillary mucinous neoplasms (IPMNs), which are rare, indolent tumours, in intestinal IPMNs, and in indolent colloid carcinomas. MUC2 appears to be not only a marker of this indolent pathway, but also partly responsible for its less aggressive nature. Thus, in pancreatic neoplasia, MUC1 and MUC2 have potential diagnostic and prognostic value as markers of aggressive and indolent phenotypes, respectively, and have potential as therapeutic targets.

Molecular findings in Barrett's epithelium

Barrett's metaplasia is a premalignant condition and remains the number one risk factor for developing adenocarcinoma. The histologic changes leading to adenocarcinoma are accompanied by genetic disturbances of the epithelial cells itself as well as the surrounding stroma. Genetic and epigenetic events affect the cell cycle, leading to growth self-sufficiency and ignoration of antigrowth signals. The balance of cell turnover is instable by avoidance of apoptosis and a general limitless of the replicative potential of the (mutated) stem cells. Sustained angiogenesis, not only a consequence of chronic inflammation, may precede invasion of genetically instable (aneuploid) cells. The principal genetic changes in Barrett's carcinogenesis are comparable to those known from other epithelial malignancies. Loss of p16 gene expression (by deletion or hypermethylation), the loss of p53 expression (by mutation and deletion), the increase in cyclin expression, and the losses of Rb, APC as well as various chromosomal loci have been reported. Since these genetic or epigenetic alterations are neither tumor nor stage specific, they could not gain diagnostic significance as biomarkers until now.