Protein expression of c-erbB-2 and p53 in normal ducts, ductal carcinoma in situ and invasive carcinoma of the same breast.

CONTEXT AND OBJECTIVE Breast cancer is thought to derive from progressively aberrant, non-invasive breast lesions, but it is not known exactly how invasive breast cancer develops from these lesions. The aim of this study was to verify the changes in c-erbB-2 and p53 protein expression between non-neoplastic ducts, ductal carcinoma in situ and invasive ductal carcinoma found in the same breast. DESIGN AND SETTING This was a cross-sectional study at Centro de Atenção Integral à Saúde da Mulher, Campinas, Brazil. METHODS Fifty-six women with invasive ductal carcinoma and ductal carcinoma in situ in the same breast were included. The expression of c-erbB-2 and p53 proteins was assessed in non-neoplastic and neoplastic cells using immunohistochemical techniques. RESULTS The c-erbB-2 protein was absent in non-neoplastic ducts but was present in 46% and 36% of in situ and invasive carcinoma components, respectively. Only 2% of non-neoplastic ducts, and 18% and 16% of ductal carcinoma in situ and invasive carcinoma components, respectively, were positive for p53 protein. No significant difference in c-erbB-2 and p53 protein expression was observed between in situ and invasive components. The nuclear grade agreement between in situ and invasive carcinoma was very good. CONCLUSIONS The invasiveness of ductal carcinoma in situ seems to be independent of the Her-2/neu and TP53 genes. The general features of an occurrence of breast carcinoma are formulated at the outset of carcinogenesis, and the Her-2/neu and TP53 genes are involved.