Prognostic significance of co-expression of c-erbB-2 oncoprotein and epidermal growth factor receptor in breast cancer patients.

The expression of c-erbB-2 oncoprotein and epidermal growth factor receptor (EGFR) was examined by immunocytochemical and radioreceptor assays in 115 patients with primary breast cancer. In 48 of 115 patients (42%), the assays were found to be positive for the expression of c-erbB-2 oncoprotein, and, in 44 of 115 (35%) patients, the assays were positive for the expression of EGFR. There was no correlation between the expression of c-erbB-2 oncoprotein and EGFR. Clinical survey demonstrated that both c-erbB-2 oncoprotein expression and EGFR expression have independent prognostic values. Furthermore, when patients were divided into three groups on the basis of the expression of both c-erbB-2 oncoprotein and EGFR, those who were found to be positive for the expression of both c-erbB-2 oncoprotein and EGFR showed a worse prognosis than other groups. These results suggest that the combination of the expression of both c-erbB-2 oncoprotein and EGFR may be important in selecting patients who have a poor prognosis.