ESR1 and breast cancer: We first examined the expression of Ki67, ER, progesterone receptor (PgR), AR, and VDR and the phosphorylation of AKT Ser473 and ERα Ser167 by immunohistochemistry (IHC) in breast cancer tissues in pre- (n = 62) and postmenopausal (n = 152) women (Tables 1 and 2, Figure 1).