The protein AGR2 is elevated in Barretts esophagus and can be used as a biomarker for distinguishing Barrett epithelium from normal esophageal epithelium.The presence of intestinal metaplasia in Barretts esophagus represents a marker for the progression of metaplasia towards dysplasia and eventually adenocarcinoma. This factor combined with two different immunohistochemical expression of p53, Her2 and p16 leads to two different genetic pathways that likely progress to dysplasia in Barretts esophagus. Also intestinal metaplastic cells can be positive for CK 7+/CK20-. Epithelial dysplasia
After the initial diagnosis of Barretts esophagus is rendered, affected persons undergo annual surveillance to detect changes that indicate higher risk to progression to cancer:  development of epithelial dysplasia (or "intraepithelial neoplasia"). Among all metaplastic lesions, around 8% were associated with dysplasia. particularly a recent study demonstrated that dysplastic lesions were located mainly in the posterior wall of the esophagus.Considerable variability is seen in assessment for dysplasia among pathologists. Recently, gastroenterology and GI pathology societies have recommended that any diagnosis of high-grade dysplasia in Barrett be confirmed by at least two fellowship-trained GI pathologists prior to definitive treatment for patients. For more accuracy and reproducibility, it is also recommended to follow international classification systems, such as the "Vienna classification" of gastrointestinal epithelial neoplasia (2000). Management
Many people with Barretts esophagus do not have dysplasia.
Bani-Hani KE and Bani-Hani KR investigated the historical aspects of the condition and found they could establish how little Norman Barrett had contributed to the core concept of this condition in comparison to the contributions of other investigators, particularly the contribution of Philip Allison.A further association was made with adenocarcinoma in 1975. References
External links

Barretts esophagus at National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Barretts esophagus Video Overview Archived 2012-05-10 at the Wayback Machine and Barretts esophagus Health Information at Mayo Clinic