Corroborating and expanding upon earlier observations in endometrial adenocarcinoma cells exposed to estradiol [42,44] and in breast cancer cells exposed to synthetic progestins with estrogenic activity [45], immunoblotting analysis revealed that estradiol significantly increased FASN protein expression in luminal A-like MCF-7/neo breast cancer cells, which was partially prevented by co-exposure to tamoxifen. The gene discussed is FASN; the disease is breast cancer.