ESR1 and breast cancer: We, therefore, acquired ER DNA binding profiles from Ross-Innes et al. (ER ChIP-seq) [23] for eight good-outcome ER+, progesterone receptor (PR)+, and HER2−, seven poor-outcome (ER+ PR− HER2− or ER+ PR+ HER2+) primary breast tumors, and three ER+ distal metastatic tumors from women with breast cancer.