Colossal crypts bordering colon adenomas in Apc(Min) mice express full-length Apc.
Enlarged but nondysplastic crypts are frequently observed at the margins of colon tumors, forming what has been called a transitional epithelium. It is now thought that this is a reactive state and not a preneoplastic condition as previously suggested. We have used the mouse familial adenomatous polyposis model, ApcMin, to study these abnormal adenoma-associated crypts. We report that these nondysplastic crypts are enormous (as much as 10 times normal length) and branch more frequently than normal crypts. They express wild-type Apc protein and display the wild-type Apc allele. We conclude that the colossal crypts at adenoma margins have normal Apc gene function, consistent with the suggestion that their phenotype is a reactive state. The cause remains an open question, but the dramatic epithelial response hints at the presence of potent epithelial trophic factors in the vicinity of colon tumors.
Bjerknes
M
M
Department of Anatomy, University of Toronto, Toronto, Ontario, Canada. bjerkness@crypt.med.utoronto.ca
Cheng
H
H
D000236:Adenoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D025601:Adenomatous Polyposis Coli Protein; D000483:Alleles; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D019656:Loss of Heterozygosity; D051379:Mice; D008855:Microscopy, Electron, Scanning; D016133:Polymerase Chain Reaction
D025601:Adenomatous Polyposis Coli Protein; D003598:Cytoskeletal Proteins