In line with this finding, other studies correlated tumor expression of RANK predominantly with worse prognostic molecular parameters such as ER-negative, HR-negative, triple-negative, or basal-like breast cancer [30, 39, 45–49, 51], higher grading [30, 39, 46, 49, 51], and higher Ki-67 [30, 39, 46, 51]. This evidence concerns the gene ESR1 and breast cancer.