The Expression of p53, c-erbB-2 and nm23 Proteins in Breast Cancer

ABSTRACT

Recently, p53, c-erbB-2 and nm23 proteins have been studied in breast cancer. The expression of p53 protein indicates the mutation of p53 gene known as a tumor supressor gene, and c-erbB-2 gene amplification has been considered an indicator of poor prognosis and nm23 a metastsis suppressor gene. In order to elucidate the roles and relations of these proteins in the develpoment, progression and metastasis in breast cancer, we studied 89 cases of invasive breast cancer and 32 cases of lymph node metastasis for the expression of p53, c-erbB-2 and nm23 proteins using an immunohistochemical method. The results were as follows 1) The expression rates of p53, c-erbB-2, and nm23 proteins in breast cancer were 40.4%, 34.8% and 55.1%, respectively. Co-expression of p53 protein and c-erbB-2 protein was found in 20.2% of cases, showing the highest incidence in poorly differentiated type (40%). 2) p53 protein expression was increased in poorly differentiated type but was not statistically significant. On the other hand, the expression of nm23 protein was decreased in poorly differentiated type, which was statistically significant (p<0.05). 3) The correlation of p53 protein expression with c-erbB-2 protein expression was statistically significant (p<0.05) but that with nm23 protein was not. 4) In the cases with lymph node metastasis, discordant expression of p53, c-erbB-2 and nm23 proteins between primary tumor and the lymph node metastatic tumor was found in 9.4%, 3.1% and 18.8% of cases, respectively. The above results suggest that overexpression of p53 and c-erbB-2 proteins and downregulation of nm23 protein are associated with the tumor progression in the breast cancer.