Parathyroid hormone related protein (PTHrP) has been identified as the major hormone responsible for the syndrome of humoral hypercalcemia of malignancy (HHM).
Although parathyroid hormone-related protein (PTHrP) is a major mediator of the syndrome, tumors also produce other hypercalcemic factors, such as tumor necrosis factor (TNF), which may modulate the effects of PTHrP.
PTHrP is a common product of squamous cancers and is the major mediator of the syndrome of humoral hypercalcemia of malignancy (HHM) by its actions through parathyroid hormone receptors in bone and kidney.
Parathyroid hormone-related protein (PTHrP) is an important humoral factor in the syndrome of humoral hypercalcaemia of malignancy (HHM) and its importance is evident by the many studies examining either PTHrP mRNA expression, intracellular peptide, or circulating PTHrP levels in patients with malignancy.
PTHrP is produced by tumors associated with the syndrome of humoral hypercalcemia of malignancy giving rise to the parathyroid hormone (PTH)-like symptoms characteristic of the syndrome.
The last 3 yr have yielded a fertile harvest of new information on the HHM clinical syndrome and on the novel peptide hormone family responsible for the syndrome.