After microdissection, DNA of 19 Barrett's adenocarcinomas, 56 Barrett's intraepithelial neoplasias (n=29 low-grade intraepithelial neoplasia (LGIN) and n=27 high-grade intraepithelial neoplasia (HGIN)), 30 Barrett's mucosa without neoplasia and normal squamous, as well as gastric epithelium, were analysed for BRAF and KRAS2 mutation.