Contribution of parathyroid hormone-related peptide to the evaluation of hypercalcemia

Rev Rhum Engl Ed. 1995 Mar;62(3):189-96.

Abstract

Hypercalcemia of malignancy is due either to local osteolysis at the site of bone metastases or to production by the malignancy of parathyroid hormone-related peptide, which shares some of the effects of parathyroid hormone. We used a radioimmunoassay (antiserum specific to the amino-terminus) to measure serum parathyroid hormone-related peptide levels in controls (n = 61), chronic renal failure patients (n = 10), patients with primary hyperparathyroidism (n = 19), cancer patients with (n = 35) or without (n = 57) hypercalcemia and/or bone metastases (n = 53 and n = 39, respectively), and patients with hematologic malignancies (n = 15). We set the upper limit of normal of the parathyroid hormone-related peptide assay at 2.7 pmol/L. The peptide was undetectable in two-thirds of healthy controls. Renal failure did not interfere with the assay. Eighteen of the 19 patients with primary hyperparathyroidism had normal levels. In contrast, 82% of patients with humoral hypercalcemia of malignancy (i.e., without detectable bone metastases) had increased levels; in this subgroup there was a significant inverse correlation between serum levels of the peptide and phosphorus. Elevation of parathyroid hormone-related peptide levels was less common among hypercalcemic patients with metastatic bone disease (38%). Four of the seven hypercalcemic patients with hematologic malignancies had elevated parathyroid hormone-related peptide levels. In our overall study population, serum calcium levels were weakly but significantly correlated with parathyroid hormone-related peptide levels. In conclusion, elevated parathyroid hormone-related peptide in a patient with hypercalcemia suggests a malignant disease.(ABSTRACT TRUNCATED AT 250 WORDS)

MeSH terms

  • Adult
  • Aged
  • Bone Neoplasms / blood
  • Bone Neoplasms / secondary
  • Calcium / blood
  • Female
  • Hematologic Diseases / blood
  • Humans
  • Hypercalcemia / blood
  • Hypercalcemia / diagnosis*
  • Hypercalcemia / etiology
  • Hyperparathyroidism / blood
  • Kidney Failure, Chronic / blood
  • Male
  • Middle Aged
  • Neoplasms / blood
  • Neoplasms / complications
  • Parathyroid Hormone / blood
  • Parathyroid Hormone-Related Protein
  • Proteins / analysis*
  • Radioimmunoassay
  • Reference Values

Substances

  • PTHLH protein, human
  • Parathyroid Hormone
  • Parathyroid Hormone-Related Protein
  • Proteins
  • Calcium