Regulation of fatty acid synthetase by progesterone in normal and tumoral human mammary glands.

Progesterone and estrogens play an important role in the control of growth, differentiation and function of mammary epithelial cells. Their mechanism of action can be studied in human metastatic breast cancer cell lines (MCF7, T47D, ZR75-1...) that contain progesterone and estrogen receptors. We used this system to try to define progestin-regulated human genes which would permit to study progestin-regulation of gene expression in cell culture and to develop clinical markers of progestin-responsiveness. This paper summarizes our investigation of the progestin-regulated 250K protein, recently identified as human fatty acid synthetase (FAS).