Lack of expression of type C hamster virus after neoplastic transformation of hamster embryo fibroblasts by benzo(a)pyrene.

Syrian hamster embryo fibroblasts transformed in vitro with benzo(a)pyrene were analyzed for the presence of type C viral components, including extra- and intracellular reverse transcriptase activity, intracellular type C hamster virus-related RNA, and cellular hamster virus group-specific antigen. No evidence could be obtained for the presence of any of these components, although they were easily detectable in hamster fibroblasts producing either B-34 virus (a hamster virus pseudotype of Harvey murine sarcoma virus which contains an excess of helper type C hamster virus) or Harvey virus itself. In addition, intracellular viral RNA could not be detected in normal hamster embryo fibroblasts, in hamster fibroblasts transformed with simian virus 40, or in newborn hamster kidney and liver. Thus the detectable expression of the indigenous hamster type C virus is not required to maintain the transformed phenotype of these cells.