Serum alpha1-foetoprotein levels in 153 male patients with germ cell tumours.

--alpha1-Foetoprotein (AFP) levels have been measured by radioimmunoassay in the serum of 153 male patients with gonadal and extragonadal germ cell tumours. Thirty-five patients with pure seminoma, and 34 patients with teratoma but without any postoperative evidence of residual or recurrent tumour, consistently had normal serum AFP levels (less than 25 ng/ml). Of 84 patients with active teratomas, 56 (67%) had serological evidence of AFP production. Ten patients with histological evidence of pure yolk sac (endodermal sinus) tumours all had raised levels. Teratomas containing yolk sac (elements may or may not be associated with raised serum levels. Trophoblastic (choriocarcinomatous) elements in a teratoma were not normally associated with high values. Fourteen patients with teratomas had elevated levels in the absence of histologically detectable yolk sac elements. Serum AFP levels often became elevated before clinical evidence of recurrence, so that AFP can act as an effective marker of the course of the disease and its response to therapy in many patients, but recurrent or progressive disease may be present in the absence of raised levels.