NEOPLASTIC HORMONE-PRODUCING CELLS OF THE PLACENTA PRODUCE AND SECRETE PARATHYROID HORMONE-RELATED PROTEIN - STUDIES BY IMMUNOHISTOLOGY, IMMUNOASSAY, AND POLYMERASE CHAIN-REACTION

BACKGROUND: Parathyroid hormone-related protein (PTHrP) was originally discovered as a product of tumors associated with hypercalcemia, Subs equent studies have demonstrated the widespread production of PTHrP in both fetal and adult tissues, among them the placenta, where it has b een identified in amniotic epithelial cells and trophoblasts. However, studies of PTHrP production by the neoplastic placenta have not been reported. EXPERIMENTAL DESIGN: We have studied placental cells and tis sues for PTHrP by immunohistology, immunoassay, and the polymerase cha in reaction. We studied normal placenta, placenta neoplasia, and place ntal cell lines grown in culture. RESULTS: Our studies in abnormal pla centa demonstrate that PTHrP is produced by chorioangioma, choriocarci nomas, and hydatidiform moles, indicating that PTHrP may be a marker f or neoplasia of the placenta. Our studies in normal placenta demonstra te that PTHrP is produced by several placental cell types, including, syncytiotrophoblast, intermediate trophoblasts, cytotrophoblasts, and amniotic epithelium, suggesting an important role for this protein in several aspects of placental function. Cell lines derived from trophob lasts and amniotic epithelium also produced PTHrP and secreted it into culture medium. Polymerase chain reaction with PTHrP coding sequence primers demonstrated the appropriate polymerase chain reaction product in these placental cells. CONCLUSIONS: The production of PTHrP by sev eral normal and abnormal placental cell types is evidence for an impor tant function for PTHrP in normal and neoplastic placenta.