SERUM PYRIDINOLINE CROSS-LINKS AS MARKERS OF TUMOR-INDUCED BONE-RESORPTION

Objective To assess serum pyridinoline (Py) and deoxypyridinoline (dPy ), using a new high-performance liquid chromatography (HPLC) method, a s a serum marker to determine the incidence of metastatic bone disease in an animal model and in the monitoring of patients with or without metastatic bone disease from prostate cancer and renal cell carcinoma (RCC). Patients, materials and methods Female C3H/He mice (8-12 weeks old) received a subcutaneous injection of tumour-cell suspensions of s erially transplanted MBT tumours. The tumour cells induced osteolysis associated with osteoclast proliferation and serum samples were evalua ted for Py and dPy using HPLC. The growth of the tumour macroscopicall y and histologically, and the extent of bone loss assessed by radiogra phy, were compared with the serum Py and dPy level, in the clinical st udy, patients with or without bone metastases from RCC (24 patients) o r prostate cancer (37 patients) were monitored using the same techniqu es and the number and extent of bone metastases compared with serum Py and dPy levels both in these patients and in 84 healthy control subje cts, Results There was a significant correlation between the bone loss evaluated by radiography and the level of serum Py in the animal mode l, Patients with bone metastases from RCC had higher values of Py and dPy than patients without known metastatic bone disease. The serum Py level increased in two patients as metastatic bone disease progressed, Similarly, in patients with prostate cancer, the mean level of serum Py and dPy was higher in patients with bone metastasis than in the con trol group, and also higher than that in patients without metastases. The serum Py and dPy levels could also distinguish patients with metas tatic bone disease with and without a lytic component. Conclusion Meas urements of serum Py appear to provide a good index of increased bone resorption induced by experimental tumours and in patients with bone m etastases from RCC and prostate cancer.