ESR1 and triple-negative breast carcinoma: By immunohistochemistry and fluorescence in-situ hybridization, the current commonly accepted molecular subtypes include luminal A (ER+/PR+/HER2−, Ki-67 < 15%), luminal B (ER+/PR+ or –/HER2 positive or negative, Ki-67 ≥ 15%), HER2-enriched (EP−/PR−, HER2 positive), and triple-negative breast cancer (TNBC) (ER−/RP−, HER2 negative).