RNA tumor virus gs antigen and tumor induction by various doses of 3-methylcholanthrene in various strains of mice treated as weanlings.

The effect of various doses of 3-methylcholanthrene on s.c. tumor induction and the occurrence of the murine C-type RNA group specific (gs) viral antigen in tumor tissue were studied in weanling mice of 8 genotypically different strains. Tumor incidence was found to be related to the dose of 3-methylcholanthrene. On the other hand, the incidence of gs antigen in the induced tumors was independent of the dose of 3-methylcholanthrene and reflected the natural gs antigen expression of the mouse strain. Histopathological examination showed no relation of tumor type to carcinogen dosage or mouse strain. The majority of the tumors examined were sarcomas. These studies confirm earlier findings, which suggested that the gs antigen expression induced in tumors is dependent on host-regulatory controls and that such controls of virogene (gs antigen) and oncogene (tumor induction) expressions of C-type RNA viral genome are independently affected by a carcinogen.