High expression of the EGFR in fibroadenomas compared to breast carcinomas.

The epidermal growth factor receptor and its ligands have been implicated as being involved in normal mammary development and breast cancer genesis. Northern blotting was used to assay the mRNA levels of the epidermal growth factor receptor and three of its ligands: the epidermal growth factor, the transforming growth factor alpha and the Amphiregulin in 16 primary carcinomas, 2 metastases and 5 fibroadenomas. In addition, the mRNA levels of the other members of the epidermal growth factor receptor family, erbB2 and erbB3 were also analysed. We found limited expression in the breast carcinomas while all the fibroadenomas showed expression at high levels. Therefore we suggest that the epidermal growth factor receptor plays an important role in the development of fibroadenomas. The erbB2 and erbB3 were more strongly expressed than the epidermal growth factor receptor in the primary carcinomas. This suggests that they could be of importance in breast carcinogenesis.