Frozen-stored mammary tissues were broken into powder with mortar and pestle. Nuclei were extracted in Farnham lysis buffer (5mM PIPES pH8.0, 85mM KCl, 0.5% NP-40 and protease inhibitors). Antibodies against STAT5A (Santa Cruz, sc-1081), GR (Thermo Scientific, PA1-511A), H3K27ac (Abcam, Ab4729), STAT3 (Santa Cruz, sc-482) were used for ChIP-seq. Libraries were prepared for sequencing using standard Illumina protocols.