Circulating placental proteins (hCG, SP1 and PP5) in trophoblastic disease

Serum human chorionic gonadotrophin (hCG), pregnancy-specific beta 1-glycoprotein (SP 1) and placental proteins 5 (PP5) levels have been measured by radioimmunoassay in 20 patients (116 samples) with hydatidiform mole, one patient (nine samples) with invasive mole and 10 patients (103 samples) with choriocarcinoma. Measurement of both serum SP1 and hCG are useful in the monitoring of these diseases. The presence of PP5 in hydatidiform mole and its absence in choriocarcinoma support the hypothesis that PP5 is closely associated with the invasive activity of malignant trophoblast.