Parathyroid hormone and calcitonin in serum of patients with mammary carcinoma.

Immunoreactive parathyroid hormone and calcitonin in serum were measured in 34 normocalcemic patients with mammary carcinoma. The mean value of parathyroid hormone was significantly higher in 26 patients with bone metastases than in 8 patients without (p less than 0.025). One patient with bone metastases had slightly raised calcitonin in serum. No difference as to parathyroid hormone values between the groups of previously irradiated and non-irradiated patients was found. A possible explanation of the normocalcemic hyperparathyroidism is presented.