ESR1 and breast cancer: We first analyzed gene expression in tumors from patients with stage I–III TNBC or ER+/human epidermal growth factor receptor (HER2)− breast cancer using the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and with stage I–III basal or luminal A breast cancer in The Cancer Genome Atlas (TCGA) BRCA bulk gene expression databases19,20.