Effect of BCG vaccination on the incidence of the development of 90Sr-induced osteosarcomas in rats

The frequency of 90Sr-induced osteosarcoma development was determined in the mongrel rats subjected to BCG vaccination. Injection of BCG (5 mg per animal) is shown to change the frequency of tumour development and their multiplicity only in male rats which were vaccinated 20 days before nuclide administration. An increase up to 10 mg per animal of BCG dose injected 10 days before 90Sr administration caused the carcinogenesis inhibition irrespective of the sex of the animals.