CLDN1 and malignant colon neoplasm: Immunoblotting results showed that expression of CAM molecules, such as claudin-1, −3 and −4, EpCAM, E-cadherin, and Tspan8 were very low in normal colon cancer cell line CCD18Co compared to Caco-2, DLD-1 and SW620 colon cancer cell lines but no expression was observed in DLD-1 cells for Tspan8.