ESR1 and invasive ductal breast carcinoma: In line with these results, clinicopathological data from 126 patients with ER+/HER2− invasive ductal carcinoma treated with estrogen modulators indicated higher HLA-ABC positivity and TIL infiltration along with a lower ER Allred score (a histological quantification of ER and PR) compared to the group receiving chemotherapy alone [29].