Expression of Cyclooxygenase-2 and p53 Protein in Colonic Adenoma with Malignant Change

Kim, Seok Hyun; Jung, Jae Hoon; Kang, Yoon Sae; Kim, Yeon Soo; Park, Ki Oh; Lee, Yeum Seok; Kim, Seon Mun; Seo, Seung Won; Seong, Jae Kyu; Lee, Byung Seok; Jeong, Hyun Yong; Song, Gyu Sang

Abstract

BACKGROUND/AIMS
The aim of this study was to investigate the value of expression of COX-2 and p53 protein in colonic adenoma with or without malignant change.
METHODS
We studied twenty-five cases of colonic adenoma with malignant change and twenty-five cases of colonic adenoma without malignant change treated by colonoscopic polypectomy in Chungnam National University Hospital from January, 1999 to July, 2002. We compared the expression of COX-2 and p53 protein by immunohistochemical stain in both group.
RESULTS
In immunohistochemical staining, the expression of COX-2 was demonstrated 68.0% (17 of 25) of colonic adenoma with malignant change and not different with that of colonic adenoma without malignant change. The overexpression of p53 protein was detected immunohistochemically in 88.0% (22 of 25) of colonic adenoma with malignant change and 32% (8 of 25) of colonic adenoma only (p <0.05).
CONCLUSIONS
The degree of COX-2 expression was similar in colonic adenoma and colonic adenoma with malignant change, but the expression of p53 in colonic adenoma with malignant change was significantly higher (p <0.05). These results suggest COX-2 might operate on early step of adenoma-carcinoma sequence. Also these results remind us that mutation of p53 gene operates on the late step of adenoma-carcinoma sequence.