Immunohistochemical detection of c-erbB-2 oncoprotein in patients with breast cancer.

Using a polyclonal antibody against the c-erbB-2 gene product, an immunohistochemical study on the expression of c-erbB-2 oncoprotein was performed in routine formalin-fixed, paraffin-embedded tissue sections from 119 patients with primary breast cancer. Overexpression of c-erbB-2 protein was detected in 35 cases (29%). There was a strongly negative association between c-erbB-2 protein overexpression and estrogen receptor status (p < 0.001). Expression of c-erbB-2 protein was found to be related to clinical stage and tumor size (p < 0.05) but not to the number of involved nodes or age of patients at diagnosis. In addition, this study demonstrated that the c-erbB-2 protein over-expression was an effective independent prognostic indicator in patients with breast cancer.