[Expression of the c-erbB-2 oncoprotein in mammary Paget's disease. Immunohistochemical study by using 3 antibodies]

An overexpression of the c-erbB-2 oncoprotein has been demonstrated in the breast cancer and has been associated with a poor prognosis. Our study involved 23 cases of mammary Paget's disease which was found to be associated with the intraductal carcinomas in 13 cases, the intraductal carcinomas supposed micro-invasive in 2 cases, the infiltrating ductal carcinomas with predominant intraductal component in 6 cases and the infiltrating ductal carcinomas in 2 cases. The presence of c-erbB-2 oncoprotein has been determined immunohistochemically with 3 different antibodies: rabbit anti-human c-erbB-2 oncoprotein A485 (Dako), c-erbB-2 oncoprotein (internal domain) mouse monoclonal antibody NCL-CB11 (Novocastra), and c-erbB-2 oncoprotein (external domain) mouse monoclonal antibody NCL-CBE1 (Novocastra). An overexpression of the c-erbB-2 oncoprotein has been observed in 21 of the 23 studied cases. We noted an intense membrane staining in the intraepidermal or intraglandular tumour cells of mammary Paget's disease. Any staining has been observed in 2 cases with glandular component of pure intraductal type. These results are identical whatever the antibody used. In a previous study concerning mammary Paget's disease, it has been noted a correlation between this overexpression and presence of large malignant cells. We also have found this notion in mammary Paget's disease where the c-erbB-2 positive neoplastic cells in the different tumour components were large with prominent cytoplasm. The obtained results argue strongly for adenocarcinomatous origin for mammary Paget's disease and exhibit that the overexpression of c-erbB-2 oncoprotein was not constantly in correlation with a poor prognosis.