Barrett's Esophagus and Esophageal Adenocarcinoma, Searching for Reliable Diagnostic RNA Plasma-based Biomarkers

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