ESR1 and triple-negative breast carcinoma: These subtypes include luminal type A (ER+, PR+, HER2−), luminal type B (ER+, PR−/high Ki67, HER2+/−), HER2 subtype (ER−, PR−/low Ki-67, HER2+), and triple-negative breast cancer (TNBC) subtype (ER−, PR−/low Ki67, HER2−) (4).