Although Cdx2 expression was observed throughout the midgut endoderm in Id2−/− embryos, similar to the wild type, Cdx2-negative regions were observed in the midgut endoderm of Id2−/− embryos (Fig. 3C), in accordance with discontinuous Cdx2 expression in the epithelium of intestinal tumors in Id2−/− adult mice (Fig. 2F). Here, CDX2 is linked to intestinal neoplasm.