[Hormonal regulation of GCDFP-15 secretion in breast tumors. Study of cultured cells].

We studied the hormonal regulation of the Gross Cystic Disease Fluid Protein 15 kd (GCDFP-15) which is secreted by mammary epithelial cells. Its precise role is still unknown. For some authors, it is associated with a risk of breast cancer, and for others with a functional differentiation of the cells. We measured the secretion of GCDFP-15 by an immunoenzymatic method in culture media and cytosols of mammary epithelial cells MCF-7, MDA-MB-231 and HBL-100. We also measured the GCDFP-15 secreted by explants of human tumors in organ cultures. We compared the basal values of GCDFP-15 with those obtained after estradiol, dihydrotestosterone and tamoxifen stimulations. Our results show a decrease of GCDFP-15 production with estradiol and an increase with dihydrotestosterone and tamoxifen. These variations are not systematically correlated with variations of cell growth. This study highlights the interest of GCDFP-15 as a tumoral marker; the study of GCDFP-15 level variations could be useful in the monitoring of cancer response to hormonal and/or chemotherapeutic treatment.