Radiation-induced malignancies in beagles: status of virus studies

Results of studies on the role of virus in radioinduced neoplasia showed that a retrovirus is associated with plutonium-induced bone tumors in dogs. The retrovirus continues to be produced in vitro by cell cultures established from bone tumor tissues. Retrovirus and/or virus-like DNA polymerases have not been found in normal tissue samples, or in plasma samples from plutonium-exposed or control animals. Likewise, no polymerase activity has been detected in plutonium-induced lung tumors. However, experiments with cell cultures prepared from plutonium-induced lung tumors have revealed the presence of a virus-like DNA polymerase associated with a cytoplasmic particulate fraction having a buoyant density of 1.20 to 1.18 g/ml