Barrett's esophagus and esophageal cancer: an overview

Although esophageal cancer (EC) is the eighth most common cancer in several European countries, it is one of deadliest worldwide. The most frequent predisposing factor implicated in its development is Barrett's esophagus (BE), an acquired metaplastic transformation of the esophageal lining cells from normal squamous epithelium into specialised or intestinal-like columnar epithelium. The major risk factor for BE is gastroesophageal reflux disease. Although BE is in itself a benign and often asymptomatic disorder, its clinical importance stems from the recognition that it represents the main precursor lesion for the development of esophageal adenocarcinoma (AC), a tumor that is rapidly increasing especially in developed countries and is associated with a low survival rate. This paper provides an overview of the epidemiology and natural history of BE as well as of the possible pathogenetic mechanisms underlying the development of BE and its progressive transition to AC. New diagnostic tests are described, recommendations for screening and surveillance are provided and surgical and ablative procedures to treat dysplastic lesions and early neoplasia are discussed. Claimed chemopreventive agents and biomarkers that in the near future may help identify people with a higher risk of EC are also considered.     

Barrett's esophageal adenocarcinoma

Barrett's esophageal adenocarcinoma arises in Barrett's epithelium, which is grouped with gastro-esophageal reflux disease (GERD). Although the incidence of esophageal adenocarcinoma is very low in eastern countries, including Japan, it has been increasing markedly and is similar to that of squamous cell carcinoma in the western countries. Surveillance, endoscopic treatment, and chemoprevention using COX-2 inhibitors have recently been developed for dysplasia or mucosal cancer in Barrett's esophagus. Barrett's esophageal adenocarcinoma is diagnosed by endoscopy and by biopsy specimens pathologically. Surgical resection has been a mainstream treatment but definitive or neoadjuvant chemoradiotherapy has recently been performed.     

p53 gene mutations in Barrett's epithelium and esophageal cancer

Genomic DNA was extracted from archival pathology specimens comprising 10 squamous and 14 adenocarcinomas, including 7 with Barrett's epithelium adjacent to tumor, and corresponding normal esophagus from the resection margin. The polymerase chain reaction was used to amplify selected exons of p53 which were analyzed for mutations using single-strand conformation polymorphism analysis. Mutations were localized to exon 8 for 1 adenocarcinoma and to exon 5 for 1 squamous tumor and 4 of 7 Barrett's specimens. Sequencing confirmed mutations at codons 273 (CGT----CAT; adenocarcinoma) and 176 (TGC----TTC; squamous) and in Barrett's epithelium at codons 152 (CCG----CTG), 155 (ACC----GCC) and 175 (CGC----CAC). Specimens of Barrett's epithelium from separate sites had identical p53 mutations suggesting a clonal origin. Cancers arising in mutant epithelium did not have mutations corresponding to those found in the Barrett's specimens suggesting that other events are required for tumorigenesis.     

Biomarkers of esophageal adenocarcinoma and Barrett's esophagus

The rising incidence and poor prognosis of esophageal adenocarcinoma in the Western world have intensified research efforts into earlier methods of detection of this disease and its relationship to Barrett's esophagus. The progression of Barrett's esophagus to adenocarcinoma has been the focus of particular scrutiny, and a number of potential tissue and serum-based disease biomarkers have emerged. The epidemiology and pathogenesis of esophageal adenocarcinoma are outlined. Tissue biomarkers allowing risk stratification of Barrett's are reviewed as well as strategies currently being used to discover novel biomarkers that will facilitate the early detection of esophageal adenocarcinoma. Finally, the uses of biomarkers as predictive tests for targeted treatments and as surrogate endpoints in chemoprevention trials are considered.     

Mutation analysis of PIK3CA and PIK3CB in esophageal cancer and Barrett's esophagus

Mutation of PIK3CA, the gene coding for the p110alpha catalytic subunit of phosphoinositide 3-kinase (PI3K), has been reported in a limited range of human tumors. We now report that PIK3CA is also mutated in esophageal tumors. Single-strand conformational polymorphism (SSCP) and denaturing high-performance liquid chromatography (DHPLC) were used to screen all 20 exons of PIK3CA in 101 samples from 95 individuals with esophageal cancer and/or Barrett's esophagus. Somatic mutation of PIK3CA was detected in 4 of 35 (11.8%) of esophageal squamous cell carcinomas (SCC) and 3 of 50 (6%) adenocarcinomas. No mutations were detected in any of 17 samples of Barrett's esophagus. For PIK3CB, we screened exons 11 and 22, which code for the regions corresponding to the exon 9 and 20 mutational 'hotspots' of PIK3CA. No somatic changes were detected in PIK3CB This study extends previous observations in other tumor types by demonstrating the presence of somatic PIK3CA mutations in both SCC and adenocarcinoma of the esophagus, thus implicating the PI3K pathway in the initiation and/or progression of esophageal cancers.     

Global gene expression profiling in Barrett's esophagus and esophageal cancer: a comparative analysis using cDNA microarrays

In order to identify and contrast global gene expression profiles defining the premalignant syndrome, Barrett's esophagus, as well as frank esophageal cancer, we utilized cDNA microarray technology in conjunction with bioinformatics tools. We hybridized microarrays, each containing 8000 cDNA clones, to RNAs extracted from 13 esophageal surgical or endoscopic biopsy specimens (seven Barrett's metaplasias and six esophageal carcinomas). Hierarchical cluster analysis was performed on these results and displayed using a color-coded graphic representation (Treeview). The esophageal samples clustered naturally into two principal groups, each possessing unique global gene expression profiles. After retrieving histologic reports for these tissues, we found that one main cluster contained all seven Barrett's samples, while the remaining principal cluster comprised the six esophageal cancers. The cancers also clustered according to histopathological subtype. Thus, squamous cell carcinomas (SCCAs) constituted one group, adenocarcinomas (ADCAs) clustered separately, and one signet-ring carcinoma was in its own cluster, distinct from the ADCA cluster. We conclude that cDNA microarrays and bioinformatics show promise in the classification of esophageal malignant and premalignant diseases, and that these methods can be applied to small biopsy samples.     

Artificial neural networks and gene filtering distinguish between global gene expression profiles of Barrett's esophagus and esophageal cancer

cDNAmicroarrays, combined with bioinformatics analyses, are becomingincreasingly used in current medical research. Existing analytic methods,particularly those that are unsupervised, often have difficulty recognizing subtle differences among predefined subgroups. In contrast, supervised methods, such as Artificial Neural Networks (ANNs), are able to recognize subtly different biological entities. We applied ANNs in a proof-of-principle study of cDNA microarray data in esophageal cancer (CA) and premalignancy. cDNA microarrays, each containing 8064 clones, were hybridized to RNAs from 22 esophageal lesions, including 14 Barrett's esophagus (BA) metaplasias and 8 esophageal carcinomas (3 squamous cell carcinomas and 5 adenocarcinomas). Scanned cDNA microarray data were analyzed using the bioinformatics software Cluster/TreeView, Significance Analysis of Microarrays (SAM), and ANNs. Cluster analysis based on all 8064 clones on the microarrays was unable to correctly distinguish BA specimens from CA specimens. SAM then selected 160 differentially expressed genes between Barrett's and cancer. Cluster analysis based on this reduced set still misclassified 2 Barrett's as cancers. The ANN was trained on 12 samples and tested against the remaining 10 samples. Using the 160 selected genes, the ANN correctly diagnosed all 10 samples in the test set. Finally, the 160 genes selected by SAM may merit further study as biomarkers of neoplastic progression in the esophagus, as well as in elucidating pathological mechanisms underlying BA and CA.     

Gene amplification in esophageal adenocarcinomas and Barrett's with high-grade dysplasia.

PURPOSE: The purpose of this study was to determine the frequency and overall contribution of specific gene amplification events in the formation of Barrett's adenocarcinomas. The relationship of gene amplification to clinical-pathological variables and its potential usefulness as a marker for early cancer detection were also examined. EXPERIMENTAL DESIGN: We used quantitative PCR and Southern blot analysis to screen 87 cases of Barrett's adenocarcinoma for the presence or absence of 13 distinct gene amplification events. Gene amplification was then examined for correlation with other amplification events and clinical variables (survival, stage, nodal involvement, tumor invasion, smoking history, and gender). Additionally, 22 specimens of Barrett's with high-grade dysplasia (HGD) were examined for the presence of gene amplification. RESULTS: One or more amplification events were present in 50 of 87 (57%) adenocarcinomas. The ERBB2 gene was amplified in 19 of 87 (21.8%), CCNE1 in 11 of 87 (12.6%), GATA4 in 9 of 87 (10.3%), KRAS in 9 of 87 (10.3%), EGFR in 7 of 87 (8.0%), CCND1 in 6 of 87 (6.8%), HNF3alpha in 5 of 87 (5.7%), PIK3CA in 5 of 87 (5.7%), C-MYC in 4 of 87 (4.6%), DYRK2 in 2 of 87 (2.3%), and AIB1, AKT1, and IGF1R were amplified in 0 of 87 (0%) of the tumors. CCND1 amplification was found to correlate negatively with survival (P < 0.05). In addition, the ERBB2 amplicon positively correlated (P < 0.05) with GATA4 amplification. Increased copy number of the ERBB2 (1 of 22), GATA4 (1 of 22), KRAS (2 of 22), C-MYC (1 of 22), CCNE1 (2 of 22), and CCND1 (2 of 22) genes was also observed in one or more Barrett's adenocarcinomas with HGD. CONCLUSIONS: The high frequency of gene amplification in esophageal adenocarcinomas and HGD indicates the important role of these events in esophageal adenocarcinoma development. Additionally, these results underscore the possible usefulness of early detection approaches and chemotherapeutic strategies (ErbB2 and cyclin D1) targeted against amplified gene products.     

食管癌和Barrett食管中RASSF2启动子甲基化的研究

 目的　研究食管癌和Barrett食管组织的甲基化情况,探讨其发生的表观遗传学分子机制的异同。方法　采用甲基化特异性PCR,对27例手术后食管癌、癌旁正常组织以及18例胃镜活组织检查Barrett食管组织中RASSF2基因的甲基化情况进行检测。结果　RASSF2在食管癌组织中甲基化率（66.7 %,18／27）高于相应癌旁正常组织（22.2 %,6／27）及Barrett食管组织的甲基化率（33.3 %,6／18）（均P＜0.05）。而Barrett食管和癌旁组织之间的甲基化率差异无统计学意义（P＞0.05）。结论　RASSF2高甲基化状态可能是引起食管癌的分子机制,在Barrett食管中需进一步验证。     

A case of Barrett's esophageal cancer showing good response to combined chemotherapy with TS-1, CDDP and radiotherapy

The patient was a 69-year-old man who, during a routine health examination, was found to have irregular mucosa in the lower esophagus, which was subsequently diagnosed by endoscopy as Barrett's esophagus. Endoscopic ultrasonography led to the diagnosis of advanced esophageal cancer with a depth of invasion corresponding to T2. While surgery was indicated, it was not considered feasible because of pleural adhesions due to old tuberculosis. Therefore, chemotherapy with TS-1 at the dose of 80 mg/day (4-week therapy followed by a 2-week withdrawal period) and CDDP at the dose of 3 mg/day (4-week of 5-day therapy followed by a 2-day withdrawal period) was instituted, followed 3 weeks later by the addition of radiotherapy with 1.8 Gy/day (5 times/week). Follow-up endoscopy revealed evident reduction in the lesion size 73 days after the start of TS-1 therapy, and complete disappearance of the lesion 185 days after the start of therapy. Grade 1 leukopenia was the only adverse effect of TS-1 noted in the patient. Treatment of Barrett's esophageal cancer is often conducted in accordance with the principles of treatment of esophageal squamous cell carcinoma, and surgical resection represents the most effective treatment. On the other hand, there have been no reports of effective adjuvant therapy. Based on our experience, the therapeutic strategy employed in this patient is considered to offer promise for the treatment of Barrett's esophageal cancer.     

Comparative Multi-Epitope-Ligand-Cartography reveals essential immunological alterations in Barrett's metaplasia and esophageal adenocarcinoma

Background  

Barrett's esophagus (BE) is caused by gastroesophageal reflux with consecutive mucosal inflammation, predisposing patients to the development of esophageal adenocarcinoma (EAC). We investigated changes in T cell-related mucosal combinatorial molecular protein patterns in both diseases using the novel Multi-Epitope-Ligand-Cartography, a unique robotic whole-cell imaging technology that simultaneously visualizes dozens of proteins in structurally intact tissues and correlates cellular localization of proteins with function.     

Abundant expression of the intestinal protein villin in Barrett's metaplasia and esophageal adenocarcinomas

Villin is a cytoskeletal protein that is involved in the formation of brush-border microvilli in normal small intestine and colon epithelium. This protein is present in Barrett's metaplasia but is reported not to be expressed in Barrett's adenocarcinoma. In this study, we analyzed villin protein expression in Barrett's metaplasia and in both Barrett's adenocarcinomas and tumors of the gastric cardia. Immunohistochemical analysis was used to evaluate the expression and cellular localization of the villin protein in 21 cases of Barrett's metaplasia, 30 cases of Barrett's adenocarcinoma, 16 cases of gastric cardia adenocarcinoma, and eight cases of adenocarcinoma of the distal esophagus. Southern, northern, and western blot analyses were used to evaluate the potential mechanisms for regulation of villin protein expression. Villin protein expression was observed in 21 of 21 cases (100%) of intestinal-type Barrett's metaplasia and in 28 of 30 cases (93%) of Barrett's adenocarcinoma and was thus highly expressed in these tumors. Northern blot analysis demonstrated villin mRNA (3.5 and 2.7 kb) in both villin-positive Barrett's metaplasia and adenocarcinomas. Western blot analysis with the antibody used for immunohistochemical analysis confirmed the presence of a single villin protein band of 95 kDa. Abundant villin expression also was present in both adenocarcinoma of the gastric cardia (13 of 16 cases; 81%) and distal esophageal adenocarcinomas of unknown origin (six of eight cases; 75%). The intestinal brush-border enzyme sucrase isomaltase was found to be present in only 22 of 46 cases (48%) of the adenocarcinomas that expressed villin. We concluded that the protein villin is highly expressed in Barrett's adenocarcinomas and is well maintained in these and other esophageal tumors. Mol. Carcinog. 22:182–189, 1998. © 1998 Wiley-Liss, Inc.