Detection of an early pregnancy factor-like substance in sera of patients with testicular germ cell tumors.

Early pregnancy factor (EPF) is produced by both maternal and fetal tissue1,2 and has been detected previously only during pregnancy.3,4 The present report describes the detection of EPF, or an EPF-like substance (tEPF), in serum from patients with germ cell tumors of the testis. tEPF, or its free components, tEPF-A and tEPF-B, were detected in all 11 patients with nonseminomatous tumors and in 5 of 10 patients with seminoma. It was not detected in serum from healthy male controls nor in patients with non-germ cell tumors or benign testicular disease. It is suggested that tEPF may be an additional serum marker for germ cell tumors and may expand the group already detectable by such markers.