ESR1 and breast carcinoma: In accordance with the well established characterization of breast carcinoma subtypes [18, 25, 26], luminal breast cancer samples were characterized by CK8-18+, CK5−, CK14−, ER+, PR+/−, HER2+/−, ALDH1−, while basal breast carcinomas were CK8-18−, CK5+, CK14+, ER−, PR−, HER2−, ALDH1+ [25] (Table 1, Figure 1A).