Successful transplantation of human hepatoblastoma into immunodeficient mice.

Six hepatoblastomas (HBs) from pediatric patients were transplanted into immunodeficient NMRI nu/nu mice. Cells from two fetal HBs did not develop tumors. In contrast, xenografts derived from three nonpretreated HBs and one HB after three courses of chemotherapy, all comprising embryonal cells, showed growth after 8 to 10 weeks. The take rates of HB varied from 60% to 90% (mean, 80%). Histologically, they resembled their originals in the pattern of fetal and embryonal differentiated areas and contained hematopoietic foci. The tumors produced high levels of alpha-feto-protein in the patients and the animals. In contrast to the patients, tumor-bearing mice did not display elevated platelet counts. During serial grafting, growth rates of the tumors gradually increased, and hematopoiesis was no longer detectable; however, histologically, a dedifferentiation could not be clearly identified. The addition of viable human or murine fibroblasts to inoculated cells of three nude mouse HBs resulted in a significant increase in the growth rate of all tumors and reappearance of hematopoiesis in three of the examined 10 xenografts of one HB. The authors conclude that HB xenografts in immunodeficient mice are a feasible in vivo model for studies of the biological behavior of this tumor.