The CDX-2 protein is a homeobox transcription factor expressed in the nuclei of intestinal epithelial cells,[5][6] playing an essential role in the development and function of the digestive system.

In common with the two other Cdx genes, CDX2 regulates several essential processes in the development and function of the lower gastrointestinal tract (from the duodenum to the anus) in vertebrates.

This differentiation is dependent on CDX2,[10][11] as illustrated by experiments where the expression of this gene was knocked-out or overexpressed in mice.

[9] Ectopic expression of CDX2 was reported in more than 85% of the human patients with acute myeloid leukemia (AML).

[14][15] CDX2 is also implicated in the pathogenesis of Barrett's esophagus where it has been shown that components from gastroesophageal reflux such as bile acids are able to induce the expression of an intestinal differentiation program through up-regulation of NF-κB and CDX2.