Circulating concentrations of specific placental proteins (human chorionic gonadotropin, pregnancy-specific beta-1 glycoprotein, and placental protein 5) in untreated gestational trophoblastic tumors.

Serum levels of human chorionic gonadotropin (hCG), pregnancy-specific beta-1-glycoprotein (SP1), and placental protein 5 (PP5) were measured prior to treatment in 14 patient with hydatidiform mole and in nine patients with choriocarcinoma. Measurement of circulating levels of SP1 and PP5, but not hCG, provides a distinction between benign and malignant gestational trophoblastic tumors.