NR4A1 and breast cancer: Previous studies showed that pre-operative endocrine therapy, pre-operative chemoendocrine therapy, and NAC induced a significant decrease in the expression of PR in breast cancer patients with hormone receptors positive (32, 33), highlighting the potential role of sex hormones in PR expression, which is consistent with our finding that decreased estradiol and testosterone levels were associated with reduced PR expression in patients with hormone receptors positive.