Immunohistochemical study of TGF-alpha, TGF-beta1, EGFR, and IGF-1 expression in human breast carcinoma.

Localization of growth factors such as transforming growth factor alpha (TGF-alpha) and beta1 (TGF-beta1), insulin-like growth factor 1 (IGF-1), and epidermal growth factor receptor (EGFR) in breast cancer tissue is controversial. We immunohistochemically investigated expression patterns of these growth factors and EGFR along with estrogen receptor (ER) status in 36 breast carcinomas (21 invasive ductal, 11 invasive lobular, 4 noninvasive ductal) and compared the results with those found in 10 fibroadenomas. Twenty-four of 36 carcinomas and all of the 10 fibroadenomas showed positivity for ER. TGF-alpha was immunoreactive in all of the carcinomas and fibroadenomas. TGF-beta1 was negative in all of the invasive ductal carcinomas and positive in all of the fibroadenomas and in five lobular carcinomas. EGFR was regularly expressed preferentially in the myoepithelial cells of mammary ducts in the fibroadenomas and in nontumorous glands. Six of the 36 carcinomas were positive for EGFR. Those tumors were negative for ER (P < .001). There was IGF-1 expression in all of the cases of carcinoma and fibroadenoma. We conclude that TGF-alpha is expressed abundantly in invasive and intraductal breast carcinomas and in fibroadenomas. EGFR expression significantly correlates with negative ER status in breast carcinoma. In breast carcinoma, IGF-1 is broadly expressed by the tumor as well as by stromal cells and might act as a growth stimulator in endocrine, paracrine, and autocrine manners.