Evaluation of the Accuracy of Asprosin as a Biomarker in Breast Cancer

<b>Background:</b> Asprosin is a fasting-induced adipokine involved in metabolic regulation and has recently been implicated in cancer biology. However, data regarding its diagnostic accuracy and clinicopathological associations in breast cancer remain limited. <b>Methods:</b> Serum asprosin levels were measured in patients with breast cancer and healthy controls using ELISA. Associations between serum asprosin levels and clinicopathological parameters were analyzed, and accuracy performance was evaluated using receiver operating characteristic (ROC) curve analysis. <b>Results:</b> Serum asprosin levels were significantly higher in the breast cancer group compared with controls (14.3 ng/mL vs. 11.0 ng/mL; <i>p</i> < 0.001). ROC curve analysis identified an optimal cutoff value of 12.2 ng/mL based on the Youden index, yielding a sensitivity of 66.4% and a specificity of 65.5%, indicating statistically significant yet moderate accuracy performance. A statistically significant difference in serum asprosin levels was observed according to HER2 status, smaller tumor size, and early-stage disease (<i>p</i> < 0.05). Serum asprosin levels tended to be higher in patients without axillary lymph node metastasis; however, this difference did not reach statistical significance (<i>p</i> = 0.050). No significant associations were observed with estrogen receptor positivity or the Ki-67 proliferation index. Serum asprosin levels were also correlated with body mass index and breast cancer presence (Spearman's rho, <i>p</i> < 0.01). <b>Conclusions:</b> Serum asprosin levels are elevated in patients with breast cancer and demonstrate moderate accuracy performance. Increased levels observed in early-stage disease suggest that asprosin may reflect early tumor biological characteristics rather than overall tumor burden. Further large-scale and longitudinal studies are required to validate its clinical utility.