Genetic Basis of the Barrett???s Metaplasia, Dysplasia, Adenocarcinoma Sequence:

Expression of the putative stem cell marker Musashi-1 in Barrett's esophagus and esophageal adenocarcinoma

The cancer stem cell theory states that cancers contain tumor-forming cells that have the ability to self-renew as well as give rise to cells that differentiate. Cancer stem cells have been identified in several solid tumors, but stem cells in normal human esophagus or in Barrett's esophagus or adenocarcinoma have not been reported. Musashi-1 is expressed by the crypt base columnar cells identified as intestinal stem cells. In other diseases of the gastrointestinal tract, local inflammation of the tunica mucosa may be an initiating factor of alteration of focal tissue 'niches,' where dormant stem cells locate. The present study investigated whether Musashi-1 is expressed in the esophagus and its relation to immune inflammation of the mucosa in Barrett's esophagus and esophageal adenocarcinoma. A total of 41 esophageal tissue specimens from 41 patients were studied. Of these, 15 were esophageal adenocarcinoma, 17 were Barrett's esophagus (10 intestinal metaplasia and 7 dysplasia), and 9 were normal squamous esophagus tissue specimens from patients without esophageal pathology. Immunohistochemistry was performed using antibodies to Musashi-1 and to a set of cell type-specific markers. A multiplexed tandem polymerase chain reaction method was used to measure the relative mRNA expression levels of Musashi-1 and the specific dendritic cell marker dendritic cell-specific intercellular molecule-3 (ICAM-3)-grabbing nonintegrin. Immunohistochemistry demonstrated the presence of small numbers of Musashi-1+ cells scattered in the connective tissue stroma and within the epithelium in cardiac-type glands in biopsies from patients without Barrett's esophagus. Musashi-1 expression was present in Barrett's intestinal metaplasia and in dysplastic Barrett's in which the majority of epithelial cells in individual glands expressed this antigen. Expression of Musashi-1 was highest in esophageal adenocarcinoma, where it was most intense in glands that displayed features of early stages of adenocarcinoma formation. In contrast, Musashi-1 staining level was weaker in glands that displayed features of advanced adenocarcinoma. Double immunostaining with proliferating cell nuclear antigen showed low proliferation in the vast majority of Musashi-1+ cells. Musashi-1 mRNA expression levels were significantly higher in esophageal adenocarcinoma than in normal esophagus or Barrett's esophagus tissues. Dendritic cell-specific intercellular molecule-3 (ICAM-3)-grabbing nonintegrin (DC-SIGN) mRNA expression levels were significantly increased in both Barrett's tissues and adenocarcinoma tissues. Expression of the putative stem cell marker Musashi-1 is absent in normal squamous epithelium, weak in esophageal cardiac-type glands and Barrett's esophagus, and markedly increased in adenocarcinoma, especially in glands displaying features of early cancer development. Musashi-1 expressing cells may be significant in the etiology of Barrett's esophagus and adenocarcinoma, and perhaps even a cell of origin for this disease. We speculate that immune inflammation occurring in Barrett's esophagus alters the mucosal microenvironment in a manner which is favorable to the activation of dormant stem cells.

Dendritic cell-associated immune inflammation of cardiac mucosa: a possible factor in the formation of Barrett's esophagus

BACKGROUND

The development of Barrett's esophagus is poorly understood, but it has been suggested that cardiac mucosa is a precursor of intestinal type metaplasia and that inflammation of cardiac mucosa may play a role in the formation of Barrett's esophagus. The present study was undertaken to examine the presence and distribution of immune-inflammatory cells in cardiac mucosa, specifically focusing on dendritic cells because of their importance as regulators of immune reactions.

MATERIAL AND METHODS

Endoscopic biopsy specimens were obtained from 12 patients with cardiac mucosa without Barrett's esophagus or adenocarcinoma and from 21 patients with Barrett's esophagus without dysplasia (intestinal metaplasia). According to histology, in nine of the 21 specimens with Barrett's esophagus, areas of mucosa composed of cardiac type epithelium-lined glands were present as well. Immunohistochemical staining and electron microscopy were used to examine immune-inflammatory cells in paraffin-embedded sections.

RESULTS

Immune-inflammatory cells, including T cells, B cells, dendritic cells, macrophages, and mast cells, were present in the connective tissue matrix that surrounded cardiac type epithelium-lined glands in all patients with cardiac mucosa. Clustering of dendritic cells with each other and with lymphocytes and the intrusion of dendritic cells between glandular mucus cells were observed. In the Barrett's esophagus specimens that contained cardiac type glands, computerized CD83 expression quantitation revealed that there were more dendritic cells in cardiac mucosa than in intestinal metaplasia.

CONCLUSION

Immune-inflammatory infiltrates containing dendritic cells are consistently present in cardiac mucosa. The finding of a larger number of dendritic cells in areas of cardiac mucosa in Barrett's esophagus biopsies suggests that the immune inflammation of cardiac mucosa might play a role in modifying the local tissue environment to promote the development of specialized intestinal type metaplasia.

Dendritic cells in Barrett's esophagus and esophageal adenocarcinoma

BACKGROUND

Like other premalignant conditions that develop in the presence of chronic inflammation, the development and progression of Barrett's esophagus is associated with the development of an immune response, but how this immune response is regulated is poorly understood. A comprehensive literature search failed to find any report of the presence of dendritic cells in Barrett's intestinal metaplasia and esophageal adenocarcinoma and this prompted our study.

MATERIAL AND METHODS

We used immunohistochemical staining and electron microscopy to examine whether dendritic cells are present in Barrett's esophagus and esophageal adenocarcinoma. Immunohistochemical staining with CD83, a specific marker for dendritic cells, was performed on paraffin-embedded sections of Barrett's intestinal metaplasia (IM, n = 12), dysplasia (n = 11) and adenocarcinoma (n = 14).

RESULTS

CD83+ cells were identified in the lamina propria surrounding intestinal type glands in Barrett's IM, dysplasia, and cancer tissues. Computerized quantitative analysis showed that the numbers of dendritic cells were significantly higher in cancer tissues. Double immunostaining with CD83, CD20, and CD3, and electron microscopy demonstrated that dendritic cells are present in Barrett's esophagus and form clusters with T cells and B cells directly within the lamina propria.

CONCLUSIONS

These findings demonstrate that dendritic cells are present in Barrett's tissues, with a significant increase in density in adenocarcinoma compared to benign Barrett's esophagus. Dendritic cells may have a role in the pathogenesis and immunotherapy treatment of Barrett's esophagus and adenocarcinoma.

Antireflux surgery for Barrett's oesophagus

Barrett's oesophagus is usually the result of severe reflux disease. Relief of reflux symptoms is the primary aim of treatment in patients with Barrett's oesophagus who do not have high-grade dysplasia. Some studies with medium-term (2-5 years) follow up show that antireflux surgery can provide good or excellent symptom control, with normal oesophageal acid exposure, in more than 90% of patients with Barrett's oesophagus. Antireflux surgery, but not medical therapy, can also reduce duodenal nonacid reflux to normal levels. There is no conclusive evidence that antireflux surgery can prevent the development of dysplasia or cancer, or that it can reliably induce regression of dysplasia, and patients with Barrett's oesophagus should therefore remain in a surveillance programme after operation. Some data suggest that antireflux surgery can prevent the development of intestinal metaplasia (IM) in patients with reflux disease but no IM. The combination of antireflux surgery plus an endoscopic ablation procedure is a promising treatment for patients with Barrett's oesophagus with low-grade dysplasia.