HYPERCALCEMIA OF CANCER

Excerpt

To the Editor: In the editorial note on the measurement of parathyroid hormone (PTH) (1) Dr. Reiss points out that immunoassayable parathyroid hormone has been found in the serum of hypercalcemic patients with nonparathyroid tumors. In the study by Berson and Yalow (2), which is referred to, the immunoassays were actually done on sera from normocalcemic patients with bronchogenic carcinoma. Many of these patients had higher than normal plasma concentrations of immunoassayable PTH. The lack of hypercalcemia in these patients could be interpreted as a negative endogenous bioassay and may reflect on the adequacy of the immunoassay as a measure