[Mouse hepatoblastoma: comparative aspects]

The structure of 12 spontaneous hepatoblastomas found in old (average age 26.5 months) male mice is described. There were considerable strain differences in their incidence: 0.5% (1/194), 0.5% (1/194) and 5% (10/198) in strain C57B1, CBA and F1 (CBA X C57B1), respectively. This proves the importance of genetic factor the role of which in the development of human hepatoblastoma is not established so far. Mouse hepatoblastoma develops almost invariably within or adjacent to liver cell tumours (adenoma or carcinoma). There was a correlation between the incidence of liver cell tumours within a given strain treated with different doses of carcinogen but such correlation was absent in mice of different strains. Histologically and ultrastructurally, mouse hepatoblastoma corresponds to the anaplastic variant of human hepatoblastoma. As distinct from human tumour, mouse hepatoblastoma does not contain alpha-fetoprotein. One tumour was transplanted to the syngeneic host and passed 30 transplant generations retaining the structure of a primary tumour with areas of osteoid tissue and foci of squamous cell metaplasia. Mouse hepatoblastoma may be induced by carcinogens. Likewise, according to the literature, risk of hepatoblastoma is higher in children whose mothers were exposed to the potential carcinogens before or during the pregnancy.