Parathyroid hormone related protein (PTHrP) has similar functions to parathyroid hormone, and is able to act on the same receptors to cause bone resorption and hence raise blood calcium concentration. It was this that led to the thinking that parathyroid hormone (PTH) was secreted by endocrine tumours of the pancreas.
Few cases of PTHrP-secreting tumours have been reported. They have been shown to be large, highly vascular and malignant, although the prognosis is generally good.
Surgical resection and treatment with streptozocin and 5-fluorouracil have proved effective in reducing blood PTHrP and hypercalcaemia.