Utility of measuring serum parathyroid hormone-related protein concentration in leukemic patients with hypercalcemia for assessing disease status.

OBJECTIVE To evaluate serum parathyroid hormone-related protein (PTHrP) as a marker of hypercalcemia in leukemic patients. DESIGN AND METHODS We measured the serum levels of PTHrP, lactate dehydrogenase (LDH) and calcium in three patients with hypercalcemia due to leukemia. RESULTS Serum levels of PTHrP, LDH and calcium were elevated at admission in all patients, and these levels were reduced to within the normal range after chemotherapy. However, normalization of serum PTHrP concentration occurred more rapidly than normalization of serum LDH levels after chemotherapy. The increase in serum PTHrP concentration accompanied leukemic cell proliferation and preceded the increases in serum LDH and calcium. Serum LDH concentration increased, but serum PTHrP concentration did not after administration of granulocyte colony-stimulating factor. CONCLUSION These findings suggest that serum PTHrP may be a more useful marker than serum LDH or calcium in assessing the status of leukemic patients with hypercalcemia.