ESR1 and neoplasm: The same trend in which BCSS was best in the ER-positive/PR-positive subgroup than in the ER-positive/PR-negative, ER-negative/PR-positive, and ER-negative/PR-negative subgroups was still observed in subgroup analysis stratified by age, sex, race, tumor grade, T stage, histological type, acceptance of surgery, chemotherapy, or radiotherapy (Figures S1–S9 in the (Supplementary Figures).