Association between serum preptin levels and bone metastasis in newly diagnosed prostate cancer: a prospective exploratory study.

BACKGROUND: Bone health plays a critical role in prostate cancer irrespective of metastatic status at diagnosis. Preptin, a peptide hormone co-secreted with insulin, exerts osteoanabolic effects and may influence tumor-related processes through insulin/IGF-related signaling pathways. However, its role in the development of bone metastasis remains unclear. This study aimed to evaluate the association between serum preptin levels and bone metastasis in newly diagnosed prostate cancer patients.

METHODS: This prospective exploratory biomarker study included patients with newly diagnosed prostate cancer. Patients with testosterone levels <25 ng/dL, diabetes mellitus, or unreliable preptin measurements were excluded. Serum preptin levels were measured using enzyme-linked immunosorbent assay (ELISA). Bone metastatic status was determined using 68Ga-PSMA PET/CT findings. Clinical and biochemical parameters were compared between patients with and without bone metastasis. Statistical analyses were performed according to data distribution, with p < 0.05 considered statistically significant.

RESULTS: Fifty patients were included, of whom 23 had bone metastasis and 27 did not. Median age was similar between groups (68.9 vs 69.7 years, p = 0.734). Baseline prostate-specific antigen levels were significantly higher in patients with bone metastasis (p < 0.001). Serum preptin levels were comparable between groups (388.6 vs 399.6 ng/L, p = 0.763). Receiver operating characteristic analysis demonstrated no meaningful discriminatory performance of serum preptin for identifying bone metastasis (AUC = 0.525, 95% CI 0.357-0.693, p = 0.763).

CONCLUSION: Serum preptin levels were not associated with bone metastasis in newly diagnosed prostate cancer patients. These findings suggest that circulating preptin may not adequately reflect tumor-bone microenvironment interactions, highlighting the limitations of systemic biomarkers in metastatic processes. Larger longitudinal and tissue-level studies are needed to clarify the biological and clinical relevance of preptin in prostate cancer.