A common finding among these studies was the favorable prognosis associated with high expression of various immune-related gene cassettes representing admixed immune cell populations [15,19,55,56] or B cell-enriched [18,30,32,57] or T cell-enriched [17,18,33] cell populations, specifically, among ER- or HER2+ breast cancer patients [15,17,19,30,32,33,55-57]. Here, ESR1 is linked to breast cancer.