Proliferating Cell Nuclear Antigen (PCNA) Immunoexpression in Hyperplastic Polyps and Adenomas of the Appendix

The aim of this study was to compare proliferating cell nuclear antigen (PCNA) immunoexpression in hyperplastic polyps and adenomas of the human vermiform appendix. We used the monoclonal antibody PC 10 in 13 hyperplastic polyps, 27 vil lous adenomas, and 13 adenomas with undulating or flat epithelium. In both the hyperplastic polyps and the villous adenomas, the labeling indices were significantly greater in the lower third than in the upper third. The labeling indices of the flat/undulating adenomas resembled those of the upper third of the villous adeno mas. In contrast to previous findings in colorectal adenomas, there were no signifi cant differences in labeling indices between the hyperplastic polyps and the villous adenomas. We concluded that PCNA labeling indices are unlikely to be of value in the distinction between villous adenomas and hyperplastic polyps in the appendix. The results may reflect the different spectrum of appendiceal adenomas versus col orectal adenomas. Int J Surg Pathol 2(4).-2 75-280, 1995