CLDN2 and colorectal carcinoma: 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).