The nature of trophoblastic disease initiated by transplantation into immunosuppressed animals

To elucidate the nature of trophoblastic disease, trophoblastic tissue was transplanted into nu/nu mice and immunosuppressed Syrian hamsters. All tissue was successfully transplanted, with no tumorigenicity shown in either the 21 cases of hydatidiform mole (HM) or the 10 cases of invasive mole (IM). However, in seven of the nine cases of choriocarcinoma (CC), tumorigenicity was demonstrated by successful serial transplantation. Thus, the conclusion was that CC was clearly a malignant neoplasm, whereas IM and HM should be considered to be benign disease because of their cellular behavior, which was clearly distinct from that of CC in this series.