Abstract

The expression of the nuclear phosphoprotein p53, a product of tumor suppressor gene, has been noted in a number of human tumors as a tumor suppressor. nm23 is a gene associated with low tumor metastatic potential and has been proposed to be a metastasis suppressor gene. To assess the role of p53 and nm23 expression in colorectal tumorigenesis and the association with clinicopathological parameters, an immunohistochemical study for mutant p53 and nm23 was done using mouse monoclonal antibodies in 43 colorectal carcinomas, 55 tubular adenomas and corresponding normal mucosa. In the tubular adenomas, p53 expression was significantly correlated with the degree of atypism(p<0.05) but not with other variables as well as with nm23. In the colorectal carcinoma, there were evidence of some correlation between metastasis, laterality and p53; laterality, depth of invasion and nm23 expression, but without statistical significance. Other clinicopathologic features were not significantly correlated. In the aspect of 'adenoma-carcinoma sequence', normal mucosa was totally negative for both p53 and nm23, and they were increasingly expressed through tubular adenoma to carcinoma with statistical significance(p<0.05). Therefore, it is suggested that both p53 and nm23 expressions occur in and around the time of transition to carcinoma from adenoma but are not significantly associated with the infiltrative behavior and metastasis.

• Keywords: Colorectal carcinoma;p53;nm23;Tumorigenesis