Several studies have reported that each subtype also differs immunologically; for instance, a dense immune infiltration (T and B cells, macrophages and myeloid-derived suppressor cells, MDSC) has been mainly associated with high-grade histological subtypes, TNBC and HER2+ breast cancer, because it is less represented in the less aggressive Luminal A breast cancer [22,23]. Here, ERBB2 is linked to breast cancer.