Expression of p53 Protein in Colorectal Carcinoma: Comparison with PCNA reactivity

Nam, Hae Joo; Kim, Sun Young

Abstract

BACKGROUND/AIMS: The p53 protein is a tumor suppressor gene product that plays an important role in cell proliferation. The p53 mutation is the most frequently reported genetic alteration in human cancers. It has been described that p53 gene mutation is correlated with tumorigenesis in many cancers. It has also been suggested that p53 gene mutation plays an irnportant role in tumor progression and is a potential prognostic factor. We have conducted this study to evaluate the relationship of p53 gene mutation in proliferative acivity to the tumor progression of colorectal carcinoma.
METHODS
We investigated the expression of p53 protein by immunohistochemistry in colorectal carcinoma and its correlation with tumor size, histologic grade, lymph node metastasis, distant metastasis, Duke stage, and PCNA index. Also the expression of p53 protein in colorectal adenoma was examined by immunohistochemistry and the expression rate was compared with that of adenocarcinoma.
RESULTS
In colorectal carcinoma, the p53 protein was frequently expressed in the nuclei of carcinomas and the expression rate(63%) was significantly higher than that of adenoma(31%). There was no relationship between tumor size and p53 expression. P53 expression rate was not significantly correlated with lyrnph node metastasis, distant metastasis, or Duke stage. In comparison the histologic grade expression of p53 staining was significantly increased in high grade carcinoma. P53 expression rate was significantly increased in the PCNA high index group.
CONCLUSIONS
The results indicate that p53 protein expression was correlated with proliferative activity of colorectal carcinoma, but the relationship with tumor progression was uncertain. (Korean J Gastroenterol 1997;29:473-481)