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. Subsequent studies have demonstrated the widespread production of PTHrP in both fetal and adult tissues, among them the placenta, where it has been 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 tissues for PTHrP by immunohistology, immunoassay, and the polymerase chain reaction. We studied normal placenta, placenta neoplasia, and placental cell lines grown in culture.

RESULTS

Our studies in abnormal placenta demonstrate that PTHrP is produced by chorioangioma, choriocarcinomas, and hydatidiform moles, indicating that PTHrP may be a marker for neoplasia of the placenta. Our studies in normal placenta demonstrate 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 trophoblasts 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 several normal and abnormal placental cell types is evidence for an important function for PTHrP in normal and neoplastic placenta.