CDX2 and colorectal cancer: Among the rest, cancers with a retained expression of the transcription factor CDX2 (Caudal-related domain homeobox 2) are classified into an epithelial sub-type, corresponding to the genomic CMS2 and CMS3 groups, and colorectal cancers with a loss of CDX2 expression which also express FRMD6, HTR2B, and ZEB1 are classified into a mesenchymal sub-type, corresponding to the genomic CMS4 group.