This study enrolled a total of 465 patients with stage III-IV breast cancer, with a median age of 52.0 (interquartile range [IQR], 47.0–60.0)years and a median creatinine-cystatin C ratio (CCR) of 1.0 (IQR, 0.8–1.2). Here, CST3 is linked to breast carcinoma.