Increased "pregnancy-specific" beta1-glycoprotein in certain nonseminomatous germ cell tumors.

Schwangerschafts (pregnancy) protein No. 1 (SP1), a recently identified beta1-glycoprotein that occurs during pregnancy, was assayed in the sera of 97 men with germ cell tumors of the testis. SP1 was elevated at 11-440 ng/ml in 3 of 6 men with choriocarcinomas, in 5 of 17 men with teratomas or "teratocarcinomas" (embryonal carcinomas and teratomas), and in 5 of 50 men with embryonal carcinomas; the highest value in 143 patients with nonmalignant diseases was 9.1 ng/ml. None of 24 sera from men with seminomas and none of 5 sera from men with orchitis had elevated SP1. In the 1 patient examined, testicular choriocarcinoma SP1 had immunochemical and gel chromatographic properties similar to those of highly purified SP1 of placental origin.