Mucosal signature of the esophageal microbiota in patients with Barrett's esophagus and esophageal adenocarcinoma

Esophageal cancer represents one of the most common causes of cancer-related death. The predominant histological type in the West Countries is adenocarcinoma (EAC) of the distal esophagus. Barrett's esophagus (BE), consisting in the replacement of the normal stratified squamous epithelium with a metaplastic columnar layer, represents the only established precursor of EAC. Persistent acid stress and consequent inflammation have been proposed to cause proliferation of BE cells that may lead to the progression towards EAC.Interestingly, the microbiota has been demonstrated to exert a crucial role in health, in several gastrointestinal and extra-intestinal diseases, and also in various types of cancers. To date, important improvements in culture-independent molecular techniques have allowed the identification of the potential main bacterial actors involved in these processes, which could represent significant markers of increased cancer risk. At the same time, since gut microbiota can be modulated by a rational application of therapeutic tools, a better knowledge of the relationship between BE, EAC and the microbiota may have clear clinical implications. In the present study, we characterized the esophageal microbiota composition in patients with BE (n=10) and EAC (n=6) compared with control individuals (n=10) that did not show any pathologic signs in their esophageal mucosa at the gastroscopy. We also investigated the potential differences of the microbial profiles between the metaplastic and the adjacent areas of normal mucosa in BE patients.