ABSTRACT
BACKGROUND: Parathyroid hormone-related protein (PTHrP) is mainly responsible for hypercalcemia in squamous cell carcinomas (SCCs). METHODS: We retrospectively checked the appearance of hypercalcemia among 33 patients who died with head and neck SCC. Serum concentrations of C-terminal region of PTHrP (C-PTHrP) were measured in 15 of them. The intracellular PTHrP expression was immunohistochemically stained in 42 SCC sections obtained from the 33 before the appearance of hypercalcemia. RESULTS: Hypercalcemia appeared in 24 of the 33, and increased serum C-PTHrP levels were confirmed in 11 of 12 hypercalcemic patients. PTHrP was identified in all SCC sections, and a stronger intensity than in normal squamous epithelia was observed in 50% of those obtained within 1 year before the onset of hypercalcemia. CONCLUSION: A high incidence of PTHrP-induced hypercalcemia was shown among patients dying with head and neck SCCs. The intracellular increase in PTHrP might be observed preceding hypercalcemia.
