Parathyroid hormone‐related protein gene expression in invasive cervical tumors

Background. Parathyroid hormone‐related protein (PTHrP) is the main tumor‐derived factor responsible for the hypercalcemia of malignancy. Methods. Using a polyclonal serum to the 37‐67 region of PTHrP, and ³⁵ S‐labeled riboprobes, the authors investigated the cellular expression of PTHrP mRNA and peptide in formalin fixed, paraffin embedded sections from 16 invasive cervical tumors. In addition, the relationship among the histologic cell type, degree of differentiation, pattern of invasion, and tumor expression of PTHrP were examined. Results. PTHrP mRNA and peptide were identified in 10 of 10 and 16 of 16 tumors examined, respectively. Overall strong mRNA expression with moderate to intense intracellular staining for peptide was associated, with adenosquamous carcinoma displaying a spray pattern of invasion. Conclusion. PTHrP mRNA and peptide were observed in all cervical tumors studied. Despite their high frequency of expression of PTHrP, cervical tumors seldom give rise to humoral hypercalcemia of malignancy, but the autocrine/paracrine effects of PTHrP may be important in the growth and dedifferentiation of the malignant cell population.