CYP19A1 and breast cancer: Although available evidence regarding the role of immune infiltrate composition in luminal-like BC may appear scattered, it may be speculated that the complex interplay between HR+ tumor cells, estrogen levels and inflammatory mediators, as well as the patient’s menopausal status and the type of endocrine agent (SERM vs. aromatase inhibitor), may contribute to unbalancing the immunological properties of regulatory T cells towards a more immunosuppressive or otherwise more antitumorigenic phenotype, in the context of the luminal-like BC-TME [13].