Expression of epidermal growth factor receptor (proto-oncogene c-erbB-1) and estrogen receptor in human breast carcinoma. An immunocytochemical study of 70 cases.

In vitro studies have shown that growth factors may mediate the growth stimulatory effect of estrogen in hormone-dependent human breast carcinomas while the constitutive expression of same growth factors might by-pass the need for estrogenic stimulus in hormone-independent neoplasms. We have performed immunocytochemical analysis of the expression of epidermal growth factor receptor (EGF-R or proto-oncogen c-erbB-1) and estrogen receptor (ER) in 70 cases of human breast carcinoma. We found an inverse relationship between the expression of EGF-R and ER (Kendall's tau b = -0.1997, P < 0.03), which prompts us to conclude that ER(-) breast carcinomas may grow in a hormone-independent manner through the over-expression of the proto-oncogene c-erbB-1, which is the receptor for epidermal (EGF) and alpha transforming (TGFalfa) growth factors.