No abstract

We sought a correlation between site and morphology of colonic polyps by labeling with neoplastic and general Paneth cell markers, monoclonal antibodies Adnab-9 and anti-alpha-defensin 5, respectively. Proportions labeled by Adnab-9 and anti-alpha-defensin 5 were, respectively, 42 and 85% for adenomas, 39 and 63% for early tubular adenomas, 41 and 44% for serrated, 34 and 20% for mixed, and 11 versus 2.7% for hyperplastic polyps. Compared with hyperplastic polyps, the proportion of other polyps labeled by Adnab-9 or anti-alpha-defensin 5 was higher but this difference was more significant for distal (P = 0.008 for Adnab-9 and P = 0.0001 for anti-alpha-defensin 5) than proximal (P = 0.645 and P = 0.154, respectively) polyps. While increased labeling of all proximal polyps compared to distal ones mirrored the colonic distribution of Paneth cells, distal adenomas tended to have a higher proportion labeled by Adnab-9, suggesting that Adnab-9 labels Paneth cells associated with increased neoplastic potential.

Patients with the hamartomatous polyposis Peutz-Jeghers and familial juvenile polyposis syndromes are predisposed to colorectal cancer but lack early genetic alterations found in adenomatous premalignant lesions. We studied hamartomatous polyps for the expression of an early preneoplastic colorectal neoplasia risk marker also found in familial adenomatous polyposis patients. Retrospective, genetic, and hospital archival tissue immunohistochemistry using Adnab-9, a premalignant marker often found in Paneth-like cells (PCs), was performed on sections of polyps from eight patients with Peutz-Jeghers syndrome, eight patients with familial juvenile polyposis, and 36 hyperplastic polyp control sections. Anti-alpha-defensin 5 (AD5), a universal PC marker, was also used to label a subgroup of sections. Hamartomatous polyposis patients also underwent specific genetic analysis. Eighty-nine percent of Peutz-Jeghers syndrome polyps labeled with Adnab-9 compared with 63% for AD5; 88% of familial juvenile polyposis sections also labeled with Adnab-9. Of the 36 hyperplastic polyp sections, only four (11%) labeled with Adnab-9 and one (3%) with AD5. Adnab-9 labeling of PCs in the epithelial elements of hamartomatous colonic lesions of hereditary hamartomatous syndrome patients reflects the predisposition to colorectal cancer, further justifying early intervention strategies.