Induction of hepatocarcinoma in vivo with fetal mouse liver cells spontaneously transformed in culture and isolation of a type C RNA virus from the carcinoma cells.

A hepatic cell line, FL83B/S2, derived from C57B/6J embryos, underwent spontaneous neoplastic transformation after long-term in vitro cultivation and produced progres sively growing adenocarcinomas when inoculated into new born isologous hosts. Transformation was accompanied by a conversion from murine leukemia virus group-specific antigen negativity to group-specific antigen positivity, and a type C RNA tumor virus was isolated from the tumors. This is the first report of type C virus isolation from murine hepatocarcinomatous cells.