Alpha-fetoprotein, alpha-1-antitrypsin, and transferrin in gonadal yolk-sac tumours

Since gonadal yolk-sac tumour in pure form or as a component of mixed germ cell tumour is in the majority of patients highly malignant, its histological recognition is of great prognostic importance. Yolk-sac tumour may assume various different histological guises, which have hitherto caused considerable terminological confusion; the present paper is aimed at correlating these morphological diversities with biochemical features which are consistent with yolk-sac differentiation. Using an enzyme-bridge immunoperoxidase technique, a series of 16 gonadal germ cell tumours with a yolk-sac component were screened for the presence of alpha-fetoprotein, alpha-1-antitrypsin, and transferrin. These proteins, normally produced by human yolk sac, were demonstrable in all the morphological patterns of yolk-sac tumour we have previously described. Six malignant non-germ cell tumours were submitted to the same investigations, and no evidence of the three protein markers was found in five; one tumour, however, an oat cell carcinoma of the bronchus, stained positively for transferrin.