[The value of the parathyrin-related protein (PTH-RP) in the diagnosis of cancer-associated hypercalcemia].
BACKGROUND
The parathyrine related protein (PTH-RP) is very similar, both in structure and in function, to the PTH and is considered as a mediator in humoral hypercalcemia in cancer. The aim of this study was to know the clinical value of PTH-RP measurement.


METHODS
Serum PTH-RP concentrations were studied in 22 healthy subjects, 13 patients with primary hyperparathyroidism, 9 patients with solid neoplasms and normocalcemia, 26 patients with solid neoplasms and hypercalcemia and 4 patients with hematologic neoplasms and hypercalcemia. The PTH-RP was quantified by a competitive radioimmunoassay technique using a specific antibody of the PTH-RP 1-40 fragment. Intact parathyrine (i-PTH) was quantified by an IRMA method using 2 polyclonal antibodies (INCSTAR).


RESULTS
Fifteen (68%) of the healthy controls presented undetectable serum PTH-RP concentrations. The serum PTH-RP concentration was normal in all those patients with hyperparathyroidism. Elevated serum PTH-RP values were not found in patients with solid neoplasms and normocalcemia or in those with hematologic neoplasms and hypercalcemia. High values of PTH-RP were observed in 8 out of 9 (88%) of the patients with solid neoplasms and hypercalcemia with bone metastasis and in 7 out of 11 (63%) of the patients with bone involvement.


CONCLUSIONS
Serum parathyrine-related protein was found to be high in a large proportion of patients with solid neoplasms and hypercalcemia. Serum PTH-RP determination is useful in the clinical investigation of patients with hypercalcemia. Even in patients with bone metastasis, hypercalcemia may have a humoral background.
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D015592:Immunoradiometric Assay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood*; D009369:Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D010281:Parathyroid Hormone / Q000097:blood*; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins / Q000032:analysis*; D011863:Radioimmunoassay / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric
D015415:Biomarkers; D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins
Valor de la proteína relacionada con la paratirina (PTH-RP) en el diagnóstico de la hipercalcemia asociada al cáncer.