Recent advances in both diagnosis and treatment of hepatocellular carcinoma have improved the prognosis and changed the clinical significance of the subsequently increasing distance metastases. Pulmonary metastasis of hepatocellullar carcinoma associated

A pure epithelial human hepatoblastoma was directly transplanted to athymic Nude mice to provide a model system to study proliferation and differentiation of these tumor cells. The first transplantation selected the embryonal component of this tumor, while subsequent passages selected in addition neuroendocrine and mesenchymal cells that evolved into osteoid and bony trabeculae. The embryonal character of this hepatoblastoma was further demonstrated by the expression of glutamine synthetase mRNA and a fetal pattern of mRNAs encoding insulin-like growth factor II. However, alphafetoprotein mRNA was detectable in neither the original nor the transplanted tumors. Finally, although p53 mRNA levels were increased, no mutation was detected in the p53 gene.