Parathyroid hormone-related protein and its receptor in human glial tumors

Objective. Parathyroid hormone-related protein (PTHrP) and its mRNA have been found to be expressed in a variety of human tumors including breast, prostate, colon, lung, renal and ovarian cancers. The purpose of this study is to evaluate the expression of PTH/PTHrP receptor and ligand in human glial tumors. Methods. We examined the coexpression of PTH/PTHrP receptor and ligand in 73 glial tumors of different histological grades and 4 nonneoplastic human brain specimens and three glioblastoma cell lines, by using Western Blot analysis and immunohistochemical analysis. Results. PTHrP and PTH/PTHrP receptors were shown in the neurons, reactive astrocytes and the endothelial cells of normal brain tissue as well as tumor cells, reactive astrocytes and vasculature of nonneoplastic tissue. They were expressed at higher levels in pure astrocytic tumors as compared to tumors with oligodendroglial components. Conclusion. PTH/PTHrP receptor and PTHrP ligand are co-expressed in human glial tumors. There increased expression suggests an autocrine and/or paracrine loop may exist.