CDX2,also named as Homeobox protein CDX-2,is a 313 amino acid protein,which contains one homeobox DNA-binding domain and belongs to the Caudal homeobox family. CDX2 localizes in the nucleus and is involved in the transcriptional regulation of multiple genes expression in the intestinal epithelium. The relative expression of CDX1 to CDX2 protein may be important in the anterior to posterior patterning of the intestinal epithelium and in defining patterns of proliferation and differentiation along the crypt-villus axis. Both Cdx1 and Cdx2 genes must be expressed to reduce tumorigenic potential,to increase sensitivity to apoptosis,and to reduce cell migration,suggesting that the two genes control the normal phenotype by independent pathways.