We speculate that these differentially expressed claudins genes (CLDN2, CLDN1, CLDN14, CLDN16, CLDN18, CLDN9, CLDN12, CLDN6, CLDN8, CLDN23, CLDN5, CLDN11, CLDN7, and CLDN15) have diagnostic value in colon cancer. This evidence concerns the gene CLDN9 and malignant colon neoplasm.