Osteoprotegerin in Serum as a Novel Marker of Bone Metastatic Spread in Prostate Cancer

Abstract
Prostate cancer (PCa) is the most frequent carcinoma in men and is often complicated by skeletal metastasis (1). Because bone scintigraphy, the standard method of monitoring metastatic bone involvement, is expensive, lacks specificity, and is not particularly suitable for the follow-up of patients, various metabolic bone markers have been studied as indicators for bone metastasis in PCa patients (2)(3). Markers that reflect osteoblast proliferation, e.g., skeletal alkaline phosphatase (sALP), are reportedly useful, which is consistent with the osteoblastic reactions seen in the skeletal metastases (4).