CDX4 and acute myeloid leukemia: Linear regression analysis identified a positive correlation between Shp2-protein tyrosine phosphatase activity and Cdx4 mRNA in the bone marrow of Hox-high AML (P=0.01, n=6), but not Hox-Low AML (P>0.6, n=6) or control bone marrow (P>0.4, n=4; Figure 8b).