The role of serum osteoprotegerine in metastatic prostate cancer - a case control study

Prostate cancer is one of the most common malignant neoplastic diseases in men. Early control of the disease progression contributes significantly to survival rates and patients' quality of life. Osteoprotegerin is a dimeric glycoprotein, which affects bone metabolism and inhibits osteoclastogenesis. In the present study, we evaluated the expression of osteoprotegerin in the serum of prostate cancer patients with or without skeletal metastases.

The expression of serum osteoprotegerin, as measured by enzyme-linked immunosorbent assay, has been studied in 82 patients with locally controlled prostate cancer, in 49 patients with metastatic bone disease and in a control group of 41 healthy males. At sampling time 65/131 of included patients were newly diagnosed, while 66/131 patients were already under hormonal therapy. All eligible prostate cancer patients had histologically confirmed malignancy. Serum total prostate-specific antigen (PSA) was determined by an immunoradiometric assay. We investigated the expression of osteoprotegerin in hormone-dependent and hormone-refractory prostate cancer and its relation to disease progression.

Among the 131 patients with prostate cancer, higher osteoprotegerin and PSA concentrations have been observed in metastatic bone patients' sera (p <0.001). ROC analysis between the metastatic and locally controlled prostate cancer patients has shown a statistically significant area curve (p <0.001) and a cut-off limit of 89.6 pg/ml. Moreover, 15.3 % of patients became hormone-resistant, with osteoprotegerin values significantly increased compared with hormone-sensitive prostate cancer patients (p <0.001).

It seems that elevated levels of serum osteoprotegerin in patients with prostate cancer reflect the bone metastatic extent and may potentially be used in metastatic patients' follow-ups. Hippokratia 2016, 20(2): 133-138.