Hypercalcaemia in melanoma patients associated with increased levels of parathyroid hormone-related protein.

We analysed serum levels of calcium and parathyroid hormone-related protein (PTH-rP) in 59 patients with melanoma by immunoradiometric assay, since only a few studies have been conducted on hypercalcaemia and serum levels of PTH-rP in patients with melanoma. Hypercalcaemia was found in seven of the 59 patients with melanoma. The serum level of PTH-rP was increased in three of the 59 patients and two of the three showed hypercalcaemia. All the patients with hypercalcaemia and/or an increased level of PTH-rP had stage IV melanoma. These findings suggest that hypercalcaemia is much more common than previously reported in patients with advanced stage melanoma and that an increased serum level of PTH-rP is one of the causative factors in hypercalcaemia in melanoma. Analysis of the serum PTH-rP level will contribute to the monitoring of the clinical course of patients with advanced stage melanoma.