Tamoxifen-resistant cells display altered gene expression profile. (A) MCF7 and tamoxifen-resistant cells derived from MCF7 (TAMRM) basal mRNA levels of ESR1, BCL-2, c-MYC, PGR and TFF1 are represented normalized to h.glucoronidase. (B) Comparison of estrogen receptor (ER), Bcl-2, c-Myc and p21 baseline expression in MCF7 and TAMRM by western blot. As a suitable loading control protein could not be identified, the Ponceau S stained membrane is presented to demonstrate equal protein loading. Bands were quantified by densitometry. The value below each band represents quantified protein in respective cell line normalized to MCF7. (C) Western blot analysis of ER, Bcl-2, c-Myc and p21 expression levels in untreated MCF7 and TAMRM tumor xenografts are presented. Comparison of T47D and tamoxifen-resistant cells derived from T47D (TAMRT) basal levels of ER, progesterone receptor (PGR) and Bcl-2 protein (D) and mRNA (E) are presented where protein expression is normalized to GAPDH, while mRNA expression is normalized to h. glucoronidase. ImageJ software was used for densitometry analysis of western blots. For graphs, averages are presented with error bars indicating the standard error of the mean.