The expression of the EGFR family members in breast carcinomas

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The EGF receptor family members (EGFR, c-erbB-2, c-erbB-3 and c-erbB-4) of tyrosine kinase receptors are involved in the regulation of cell growth and differentiation. Differential expression of such members in breast carcinomas may be associated with different clinical behaviours. A series of Norwegian and Chinese breast cancer patients has been examined in our laboratory with the same immunohistochemical protocol. The expression rate of EGFR, c-erbB-2 and c-erbB-3 in these two series was similar, 43.9%, 37% and 22% in the Norwegian series and 53%, 35.8% and 17% in the Chinese series, respectively. Comparing the immunohistochemical results in available benign breast material and 'normal' material in breast carcinomas, we conclude that the expression of EGFR, c-erbB-2 and c-erbB-3 is increased in breast malignancy. The expression rate of c-erbB-4 was lower in the Chinese series, 45.7% vs 81%. That was probably due to the fact that there were more grade III tumours in the Chinese series, since the expression of c-erbB-4 was found to be inversely associated with histological grade in invasive ductal carcinomas. Compared with the expression in benign and normal breast tissues, the expression of c-erbB-4 was, however, decreased in breast carcinomas in both series. Available follow-up data in the Chinese series demonstrated that c-erbB-4 expression in node-negative breast carcinomas was associated with better prognosis, but not c-erbB-4 expression in node-positive carcinomas. It is concluded that while the expression of EGFR, c-erbB-2 and c-erbB-3 is associated with cancer development, the expression of c-erbB-4 may have a different role.