CLDN18 and malignant colon neoplasm: 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.