RARRES2 and breast cancer: ROC curve analysis was used and the results showed that the area under the ROC curve (AUC) for chemerin, CEA and CA15-3 was 0.703, 0.581 and 0.662, respectively, in distinguishing between breast cancer patients from healthy individuals, and the chemerin cutoff value was 100.327 ng/ml with a sensitivity of 56.60% and a specificity of 98.10% (Fig. 2 and Table 1).