ER/PR/HER-2 subtypes classified breast cancer patients into 8 groups: ER+/PR+/HER-2−, ER+/PR+/HER-2+, ER+/PR−/HER-2−, ER+/PR−/HER-2+, ER−/PR+/HER-2−, ER−/PR+/HER-2+, ER−/PR−/HER-2−, and ER−/PR−/HER-2+. Here, ESR1 is linked to breast cancer.