TRANSFORMING GROWTH-FACTOR-BETA SECRETION FROM PRIMARY BREAST-CANCER FIBROBLASTS

Transforming growth factor beta (TGF-beta) is a hormonally regulated g rowth inhibitor with autocrine and/or paracrine functions in human bre ast cancer. In vivo, enhanced immunohistochemical staining of extracel lular TGF-beta(1) has been detected around stromal fibroblasts in resp onse to the antiestrogen treatment. We have investigated the effects o f tamoxifen on the production of TGF-beta by primary human breast fibr oblast cultures in serum-free medium. Highly variable levels of mainly latent TGF-beta(1) were detected in conditioned media from both tumor and normal tissue derived fibroblasts. Hydroxy-tamoxifen was shown to increase latent TGF-beta(1) secretion in three of the eight tumor tis sue-derived fibroblast cultures. Such effect of hydroxy-tamoxifen was not observed in fibroblast cultures established from normal adjacent b reast tissue.