SECRETION OF PARATHYROID HORMONE-RELATED PEPTIDE IN PATIENTS WITH MULTIPLE-MYELOMA

Stimulation of bone resorption by local factors, the cytokines, is key to the development of hypercalcemia in multiple myeloma patients, Par athyroid hormone-related peptide, the systemic factor found in humoral hypercalcemia, has rarely been incriminated in myeloma, We report a c ase of myeloma with hypercalcemia and elevated serum levels of parathy roid hormone-related peptide, Bisphosphonate therapy was rapidly effec tive in correcting serum calcium levels despite persistent high levels of the peptide. Seven other cases of myeloma with hypercalcemia and h igh serum parathyroid hormone-related peptide levels have been reporte d, Expression by myeloma plasmocytes of the messenger RNA for this pep tide has also been demonstrated, These data suggest that parathyroid h ormone-related peptide may contribute to the development of hypercalce mia in some myeloma patients.