Abstract
Sixty-one murine leukemia virus-induced rat and mouse lymphomas were examined for evidence of proviral insertions adjacent to known oncogenes. Five of these lymphomas were found to have alterations adjacent to c-myc. Two of the lymphomas with altered c-myc sequences were examined in detail. Evidence was obtained showing that the alterations in the c-myc sequences in these 2 lymphomas were the result of proviral integrations. Evidently, lymphomagenesis by murine leukemia viruses can result from insertional mutagenesis of cellular oncogenes.