This study is designed to perform a explorative search of the transcriptome to detect new circulating diagnostic sensitive and specific biomarkers in patients with Barrett's esophagus or esophageal adenocarcinoma.

By developing new tools for risk-assessing of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) in a population at risk, the investigators expect that diagnosis can be done in an earlier stage resulting in an improved 5-year survival. A proof-of-concept RNA profiling study will be done in 20 BE and EAC patients where 2 biomaterials (tissue and plasma) and 2 RNA biotopes (micro RNA and messenger RNA) will be compared. Previously validated methodology on small RNA and messenger RNA capture sequencing on both tissue and plasma will be used to obtain high-quality data. Differential expression analysis will be done on tissue and plasma sample data. Additional in-depth data-mining will be done, amongst other focusing on structural information encoded in the transcriptome and building a multifeature classifier. These findings will be validated in a large validation cohort, followed by development of a clinical-grade quantitative Polymerase Chain Reaction (qPCR) test, ready for testing in an independent cohort.

Inclusion Criteria:

• Barrett's Esophagus with length > 3cm OR esophageal adenocarcinoma histologically proven
• Adequate mental faculty, allowing to understand the proposed treatment protocol and provide informed consent
• Age over 18 years
• No other concurrent malignant disease
• No inclusion in other clinical trials interfering with the study protocol
• No concurrent chronic systemic immune or hormone therapy, except neoadjuvant chemotherapy
• Absence of any severe organ insufficiency
• No pregnancy or breast feeding
• Written informed consent

Exclusion Criteria:

• Pregnancy or breast feeding
• Active bacterial, viral or fungal infection
• Parenchymal liver disease (any stage cirrhosis)
• High risk of bleeding during biopsy (anticoagulants, esophageal varices)
• Esophageal squamous cell carcinoma
• Helicobacter pylori positive at the time of biopsy sampling
• Radiofrequency ablation of the oesophagus
• Psychiatric pathology capable of affecting comprehension and judgement faculty

All patients diagnosed with Barrett oesophagus or esophageal adenocarcinoma who meet the eligibility criteria are candidates for inclusion in this study.