PARATHYROID HORMONE-RELATED PROTEIN MESSENGER-RNA AND PROTEIN EXPRESSION IN MULTIPLE-MYELOMA - A CASE-REPORT

Multiple myeloma frequently leads to complications, such as osteolytic lesions, hypercalcemia, and pathological fractures. Increased bone re sorption in myeloma is due to osteoclast activation, The nature of the osteoclast activator(s) remains unclear. We describe a case of multip le myeloma with marked hypercalcemia and skeletal complications that p rogressed rapidly despite chemotherapy. The patient had marked hyperca lcemia at diagnosis (4.5 mmol/l), and elevated parathyroid hormone-rel ated protein (PTHrP) levels were found in plasma. Analysis of the bone marrow trephine biopsy showed PTHrP gene transcription and protein in myeloma cells. These results provide strong evidence for the producti on of significant amounts: of PTHrP by human myeloma cells. PTHrP has been measured as elevated in the plasma of patients with myeloma and m ight be an important contributor to the skeletal complications in this disease.