Hypothetical model of Cdx gene regulation in normal and malignant hematopoiesis. (A) Normal hematopoiesis, based on results from studies in embryogenesis, the canonical Wnt pathway regulates the expression of CDX4 by the Lef1/Tcf complex in hematopoiesis. The FGF-MAPK pathway is not constitutively active in stem and progenitors cells. (B) Malignant hematopoiesis, either deregulation of the WNT pathway or FGF signaling induces aberrant CDX2 expression in human leukemia.