Metaplasia in Barrett’s esophagus: A specific phenotype?

Barrett’s esophagus (or columnar epithelium lined lower esophagus (CELLO) or “endobrachyoesophage” in French) is an acquired condition in which the squamous epithelium of the lower esophagus is replaced by a metaplastic glandular epithelium (1). Barrett’s esophagus represents an abnormal healing of esophageal ulceration usually secondary to severe gastroesophageal reflux disease. Although the cell of origin of Barrett’s esophagus is not firmly established, recent studies suggest that it is a multipotential stem cell of esophageal origin. The molecular mechanisms leading to metaplastic epithelium remain poorly understood. A number of gene products have been shown to be expressed during this process, including enzymes, growth factors and structural proteins. Of particular interest is the demonstration that CDX1, an intestine-specific transcription factor, may be important in the transition from normal esophageal epithelium to intestinal type metaplasia (2). It is also interesting to note that the expression of trefoil peptides (pS2 and hSP) may also participate in the delineation of the epithelial phenotype of Barrett’s metaplasia (3).