Immunohistochemical study on the expression of c-erbB-2 oncoprotein in breast cancer.

Expression of the c-erbB-2 oncogene protein was investigated by immunohistochemistry in 110 paraffin-embedded blocks of primary breast cancer. 25 (22.7%) of 110 tumors were stained positively with c-erbB-2 protein antibody. There was no correlation between c-erbB-2 immunostaining and age at diagnosis, menopausal status, hormone receptor status, tumor size, or clinical stage. The tumors with an extensive intraductal component showed a higher incidence of the c-erbB-2 expression than those without. A significantly shorter overall survival was obtained in patients with the expression of c-erbB-2 protein than in patients without. Staining of c-erbB-2 protein is an effective prognostic indicator in patients with breast cancer.