Mouse tissues were fixed in 10% (v/v) buffered formalin and embedded in paraffin. Sections of the paraffin-embedded tissues were subjected to immunohistochemical (IHC) analysis as described[8 (link)]. The following primary antibodies were used for IHC analysis: mouse anti–β-catenin (1:800; BD Biosciences, Lexington, KY), rabbit anti-p53 (1:500; Vector Laboratories Inc., Burlingame, CA), goat anti–E-cadherin (1:500; R&D Systems, Minneapolis, MN), Rabbit anti-vimentin (1:500; Epitomics, Burlingame, CA), and mouse anti-CDX2 (1:100; BioGenex, Fremont, CA). The IHC staining with anti-p53 antibody was classified according to the percentage of stained cells. Expression of p53 was considered to be weak if <10% of neoplastic cells were observed to be stained, and strong if >10% of neoplastic cells were stained.