In a recent study, Hurtado and colleagues mapped ER and FOXA1 binding in three breast cancer cell lines, MCF-7, T-47D and ZR-75-1, and determined that positioning of the silencing factor CTCF was different between the three cell lines and defined which ER targets were transcriptionally enhanced by FOXA1 binding. This evidence concerns the gene CTCF and breast carcinoma.