Barrett's esophagus: can biomarkers predict progression to malignancy?

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma. It is characterized histologically by a specialized intestinal metaplasia that replaces the squamous epithelium of the distal esophagus, and is associated with chronic gastroesophageal reflux disease and obesity. Similar to the adenoma-carcinoma sequence of colorectal carcinomas, esophageal adenocarcinoma develops through progression from BE to low- and high-grade dysplasia, then to adenocarcinoma with accumulation of genetic and epigenetic abnormalities. The exact malignancy potential of BE is uncertain. Dysplasia is the most predictive marker for risk of esophageal adenocarcinoma, whereas endoscopic and histological diagnoses are still the gold standard for surveillance of patients with BE. However, both are limited, either by sampling errors in biopsies or by differences in histological interpretation. Several studies have identified candidate biomarkers that may have predictive value and may serve as additional factors for the risk assessment of esophageal adenocarcinoma. This review discusses the role of biomarkers in the progression from BE to adenocarcinoma, focusing on clinical and molecular markers.