Detection by immunohistochemistry of c-erbB2 oncoprotein in breast carcinomas and benign mammary lesions.

The presence of the c-erbB2 oncoprotein was demonstrated by immunohistochemistry in a study involving 173 mammary lesions. The lesions included infiltrating cancers, non-invasive neoplasia, as well as atypical and benign lesions. Our aim was to investigate the correlation between the c-erbB2 oncoprotein overexpression and the morphological features of the different mammary tissues analyzed to obtain a better characterization for the growth potential of certain lesions, with emphasis placed on the non-invasive neoplasia and the atypical lesions. Nearly 30% of infiltrating ductal carcinomas (27/89 cases) and 2 out of 24 infiltrating lobular carcinomas were positive. The comedocarcinomas were mostly stained (83%). In contrast, the intraductal carcinomas of cribriform or papillar patterns were consistently negative. No staining was observed in the atypical epithelial hyperplasia located in the vicinity of positive cancers for anti-oncoprotein c-erbB2 antibody. Furthermore, the only 5 positive cases for c-erbB2 out of 32 cancer-free cases were three fibroadenomas and two fibrocystic diseases with atypical ductal hyperplasia. A close correlation was thus observed between c-erbB2 oncoprotein overexpression and cancerous cell morphology, characterized by a marked nuclear hypertrophy often associated with cellular pleomorphism. However, predictive abnormalities of malignant transformation in non-neoplastic epithelial proliferation was difficult to identify, considering only the c-erbB2 expression. A group of tumors with little nuclear abnormalities were found positive for c-erbB2 immunostaining. These probably corresponded to a particular cellular phenotype. Further studies involving other oncogenes should lead to a better characterization of the different tumor phenotypes and help to clarify breast carcinogenesis.

Determination of amplification level of the c-erbB-2 proto-oncogene in human breast carcinomas: a comparative study between non-radioactive and radioactive labelling.

A quantitative method of polymerase chain reaction (PCR) using both digoxigenin and radioactive labelled probes has been used for the detection of the c-erbB-2 proto-oncogene amplification in breast carcinomas with formalin-fixed paraffin-embedded tissue sections. c-erbB-2 proto-oncogene amplification has been demonstrated in 14 infiltrating ductal carcinomas. The technique consisted of the co-amplification of c-erbB-2 and IFN-gamma (interferon-gamma) genes. The latter was considered as a single copy gene per genome-equivalent. The aim of this study was to compare two quantitative PCR techniques based on the incorporation of either digoxigenin-11-dUTP or 32P-dCTP, during amplification. For the colorigenic method, using the Dig system, after electrophoresis and transfer, the specific bands were revealed with a chromogenic substrate of phosphatase. Their intensity estimated by scanning photometry following blot transparisation. After electrophoresis, the radioactive gel was submitted to radioautography and the band intensities evaluated by scanning spectrophotometry. For the 14 samples, a good agreement between both methods was noted. The colorigenic method is a valuable alternative to radiolabelling due to: i) time saving, ii) reagent conservation, iii) safe manipulation and iv) sensitivity of the same order for both methods.

[Expression of the c-erbB-2 oncoprotein in mammary Paget's disease. Immunohistochemical study by using 3 antibodies]. / Expression de l'oncoprotéine c-erbB-2 dans la maladie de Paget mammaire. Etude immunohistochimique à l'aide de trois anticorps.

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.