RARRES2 and breast cancer: The results showed that serum levels of chemerin were significantly associated with histologic grade, Ki67 expression levels, and menopausal status (Table 2), and serum levels of chemerin in breast cancer patients with ER-negative, PR-negative, or HER-2-negative were higher than those with ER-positive, PR-positive, or HER-2-positive, respectively, but these results were not statistically significant.