CMS4 was characterized by suppression of claudin 2, claudin 3, claudin 7, and occludin and upregulation of claudin 5 mRNAs, not aligning with any of the three TCGA genomic groups or with CMS2 despite the similarities in the prevalence of common colon cancer mutations. The gene discussed is CLDN2; the disease is malignant colon neoplasm.