Therefore, we wondered about the significance of CLDN2 upregulation in the susceptibility of patients with IBD to CAC, especially considering that CLDN2 is expressed at the crypt bottom; clusters with Cyclin-D1 and c-Myc proteins; and regulates intestinal epithelial cell (IEC) proliferation, differentiation, and migration as well as cancer stem cells in spontaneous colon cancer (CRC) (16, 17). This evidence concerns the gene CLDN2 and inflammatory bowel disease.