OCLN and inflammatory bowel disease: Tight junctions are known to have a vital role in maintaining cell-to-cell integrity, and their loss is important in the pathophysiology of a variety of gastrointestinal disorders such as IBD, irritable bowel syndrome, and even CRC.19 Therefore, mucin-associated proteins (MUC2, oligomeric mucus gel-forming protein; TFF3, mucin-associated peptide trefoil factor 3) and tight-junction structural proteins (occludin and zonula occludens-1 (ZO-1)) were measured in mRNA and protein levels.