Plasma vitamin D binding protein as the potential predictor of depressive disorder risk in breast cancer patients.

Experiencing breast cancer (BC) has been recognized as a profoundly traumatic event for women, often resulting in psychiatric complications, notably depression. Furthermore, depression can adversely impact the prognosis of BC. The purpose of this study was to determine the specific changes in circulating vitamin D binding protein (VDBP) levels and to assess its clinical significance for diagnosing and predicting depression in BC patients. 168 BC patients, including 83 depressive ones and 85 non-depressive ones, and 60 healthy controls (HCs) were recruited in the present study. 25-hydroxyvitamin D [25(OH)D], calcium, and VDBP in the blood samples were detected. A six-month follow-up study was also conducted for 83 BC patients with depression. Firstly, plasma VDBP levels were significantly increased in BC patients with depression as compared to HCs or BC patients without depression. Secondly, plasma VDBP showed the great discriminatory power for identifying BC patients with depression from those without (area under curve = 0.816). Thirdly plasma VDBP, serum 25(OH)D, and serum glial fibrillary acidic protein (GFAP) levels were significantly associated with the severity of depression in BC patients. Fourthly, the interactive effects between circulating VDBP and GFAP levels had effect on the progression of depression in BC patients. Consequently, plasma VDBP may be a potential biomarker for predicting the depressive disorder risk in BC patients.