[Radioimmunologic determination of plasma parathormone in hypercalcemia caused by cancer with osseous metastases].

The plasma parathormone was measured by radioimmunological determination in 23 cases of cancer with bone metastases, 8 of mammary origin. In 11 cases the plasma parathormone (iPTH) was less than 4 ng/ml (lower normal limit), as might be expected in view of the hypercalcemia. In 12 cases the iPTH was higher than 4 ng/ml, in 8 of these higher than 8 ng/ml (upper normal limit). These results are suggestive of the role of a substance analogous to parathormone in the genesis of the hypercalcaemia and peritumoral bone resorption of bone metastases of solid tumors.