Characteristics and Experirnental Chernotherapy of Yolk Sac Tumor of the Ovary

Abstract

Human yolk sac tumor of the ovary was transplanted in nude mice. The transplanted tumor cells had an ability to grow in this heterologous host, and produced a solid tumor, which we have designated as YST-1 tumor. 1. Histology of the YST-1 tumor showed microcystic, reticular and solid area and was similar to that of the original tumor taken from the patient, even after serially transplanted in nude mice. 2. Electron microscopic observation suggested that the YST-1 tumor cells had a high proliferative activity, and were germ cell origin. 3. Autoradiogram of tumor cells labeled with ³H-thymidine revealed that tumor cells in solid area had higher proliferative activity than those in microcystic area. 4. The prescnce of α-fetoprotein (AFP) in the cytoplasma of the YST-1 cells was demonstrated by immunofluorescent antibody staining using a antiserum against human AFP. AFP was localized mainly in microcystic area. 5. Human serum proteins and enzymes including album in, transferrin, α1-antitrypsin, alkaline phosphatase, lactic dehydrogenase and AFP were detected in sera of nude mice bearing YST-1 tumors. 6. Karyotype of YST-1 tumor was proved to be human type.
Chemotherapy of yolk sac tumor heterotransplanted to nude mice was studied. Anticancer drugs clinically known to be effective for ovarian cancer, such as Adriamycin, Carbazilquinone, 5-Fluorouracil, Cyclophosphamide, Mitomycin C, Chromomycin A₃, Vinblastine, Bleomycin and Cis-platinum diammine dichloride were administered intraperitoneally to tumor-bearing nude mice. 1. The rapeutic effects were evaluated by tumor size and relative tumor size before and after experiments. Cis-platinum, Vinblastine and Bleomycin showed the significant effect arresting the growth of YST-1 tumor. 2. Histological evaluation of effects of chemotherapy for YST-1 tumor was performed. 3. Serum AFP of mice bearing YST-1 tumor showed close correlation with tumor size (r=0.93, P<0.001).
The usefulness of this experimental system for clarifying the characteristics and searching an effective clinical treatment of the human yolk sac tumor is discussed.