Characterization of MDA-MB-231-ERβ1 expressing cells. A). Real-time PCR and Western blot analysis of MDA-MB-231-ERβ1 clonal cell lines # 4 and 12 indicating mRNA and protein expression levels of ERβ1 in the absence and presence of doxycycline (Dox). B). Real-time PCR analysis of the progesterone receptor (PR), trefoil factor 1 (PS2) and Kruppel like factor 10 (KLF10) following indicated treatments for 24 hours. P-values < 0.05 were considered to be statistically significant. *Denotes significant difference between indicated treatment and vehicle control treated cells.