Ultrastructure and immunohistochemical staining of a transplanted endodermal sinus tumor.

An endodermal sinus (yolk sac) tumor was successfully transplanted into athymic nude mice. Histologic and ultrastructural investigations revealed that the transplanted tumor had a characteristic appearance with numerous Shiller-Duval bodies, endodermal sinus structures and ultrastructural profiles as previously described in human material. The endodermal sinus tumor and normal human yolk sac have been found to synthesize not only alpha-fetoprotein (AFP), but also other serum proteins, namely, albumin, prealbumin, alpha 1-antitrypsin, and transferrin. Serological study by radioimmunoassay demonstrated AFP, carcinoembryonic antigen (CEA) and human chorionic gonadotropin (HCG) in the sera of the tumor-bearing nude mice and in cyst fluid from the transplanted tumor. Immunohistochemical investigation using the unlabeled antibody peroxidase-antiperoxidase method showed using the unlabeled antibody peroxidase-antiperoxidase method showed that the tumor cells produced CEA, alpha 1-antitrypsin, transferrin, HCG as well as AFP. These immunohistochemical staining properties were correlated with the findings on radioimmunoassay.