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

Objective. Parathyroid hormone-related protein (PTHrP) and its mRNA have be en found to be expressed in a variety of human tumors including breast, pro state, 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 7 3 glial tumors of different histological grades and 4 nonneoplastic human b rain specimens and three glioblastoma cell lines, by using Western Blot ana lysis 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 tumo r cells, reactive astrocytes and vasculature of nonneoplastic tissue. They were expressed at higher levels in pure astrocytic tumors as compared to tu mors with oligodendroglial components. Conclusion. PTH/PTHrP receptor and PTHrP ligand are coexpressed in human gl ial tumors. There increased expression suggests an autocrine and/or paracri ne loop may exist.