Cathepsin E Is a Specific Marker of Dysplasia in APCMin/+ Mouse Intestine

Transcriptional profiling of APCMin/+ mouse intestinal epithelial tissue has revealed that cathepsin E (catE) manifests high relative expression in adenomas and carcinomas relative to normal epithelium. Real-time RT-PCR data presented previously confirm the presence of catE transcript in APCMin/+ adenomatous cells compared with samples derived from normal APCMin/+ and wild-type tissue. At the protein level, strong, highly specific immunohistochemical staining for catE is displayed in dysplastic lesions of APCMin/+ mice. Using Western immunoblot analyses, it was additionally established that the urine of tumor-bearing mice contains higher levels of the monomeric form of catE than their wild-type counterparts. These results authenticate the relationship between transcript abundance and protein levels in transformed tissue and suggest potential utility for catE as a marker for the inception and progression of intestinal cancers.