Expression of β-catenin in fibrotic lesions. (A + B) In tissue samples from non-IBD control patients, the intestinal epithelial cells featured a strong staining for β-catenin in the cell membrane (black arrows) while the nuclei did not show any significant β-catenin staining (white arrows). In sub-mucosal layers almost no β-catenin was detectable (grey arrows). (C-F) In stenotic areas of CD patients clearly more cells featured nuclear β-catenin staining (black arrows) indicating transcriptionally active, meaning nuclear, β-catenin. Magnification: 10-fold, 40-fold or 100-fold, respectively. All analysed patient samples showed comparable staining characteristics when compared to samples from non-affected controls.