β-Catenin-accumulated crypts in the colonic mucosa of juvenile ApcMin/+ mice

Although ApcMin/+ mice are widely used for an animal model of human familial adenomatous polyposis (FAP), a majority of intestinal polyps locate in the small intestine. We recently reported that numerous β-catenin-accumulated crypts (BCAC), which are reliable precursor lesions for colonic adenocarcinoma, develop in the large bowel of aged ApcMin/+ mice. In this study, we determined the presence and location of BCAC in the large intestine of juvenile ApcMin/+ mice (3 and 5 weeks of age). Surprisingly, BCAC were noted in the colon of even ApcMin/+ mice of both ages, and mainly located in the distal and middle segments of the colon. Also, a few microadenomas were detected in ApcMin/+ mice of 5-week old. Our results may indicate need of further investigation of the colorectal mucosa of ApcMin/+ mice for examining colorectal carcinogenesis using ApcMin/+ mice.