Fig. 3. Basal levels of ER-a expression are downregulated by EGFR ligands TGFA and EGF in BT474 breast cancer cells. (A, B) After 24-h serum starvation, we treated cells with 50 ng/ml TGFA and EGF. Levels of ER-a mRNA and protein were detected by real-time PCR and western blots. (C, D) Under the same conditions, IL-8 mRNA and protein were detected by real-time PCR and ELISA. Results are representative of three independent experiments. Values are mean ± SEM. * P<0.05, ** P<0.01 vs. Con. Con: control.