Transforming growth factors in human breast cancer

Transforming growth factors alpha and beta (TGF alpha and TGF beta) are two growth factors which are frequently associated with a number of human breast cancer cell lines and with primary human breast carcinomas. Expression of TGF alpha protein and specific TGF alpha mRNA transcripts (4.8 and 1.6 kb) can be induced by estrogens in estrogen-responsive breast cancer cells, suggesting that the mitogenic effects of estrogen may in part be mediated through this potential autocrine growth factor. In contrast, anti-estrogens such as tamoxifen can increase the secreted levels of TGF beta, which is a potent growth-inhibitor for some human breast cancer cell lines. Anti-estrogens generally decrease TGF alpha production. TGF alpha mRNA expression has been detected in approximately 40-70% of primary human breast tumors, while expression of a 2.6 kb TGF beta mRNA transcript can be detected in 70-80% of breast tumors. Interference with (e.g. TGF alpha) or augmentation of (e.g. TGF beta) the effects of these two growth factors may have some potential clinical applications in the treatment of breast cancer.