Humoral hypercalcaemia in renal carcinoma due to parathyroid hormone related protein.

Parathyroid hormone related protein (PTHRP) has been implicated in humoral hypercalcaemia of malignancy (HHM). We describe a patient with a renal carcinoma and hypercalcaemia, and for the first time have demonstrated a 4-fold PTHRP concentration gradient across a renal tumour bed. This provides further strong evidence that the primary tumour was the source of the PTHRP. The PTHRP 1-86 content of the tumour tissue was 4.8 ng/g, similar to that previously found in tumours associated with HHM. In PTHRP-secreting tumours, PTHRP may be a useful oncological marker after surgical resection.