In view of the specificity of claudin expression profiles in human cancer, it has been revealed that claudin proteins may serve as useful molecular markers for cancer diagnostics and the expression of claudin proteins can be used as a prognostic indicator, as the loss of claudin-1 has been suggested to be correlated with a poor prognosis in patients with stage II colon cancer [35]. This evidence concerns the gene CLDN1 and colonic neoplasm.