Effect of systemic administration of BCG cell walls on bronchogenic carcinoma in hamsters.

Systemic injection of BCG cell walls was evaluated for effects on the development of respiratory tract tumors induced by intratracheal instillation of benzo[a]pyrene plus Fe2O3 in Syrian hamsters. Only 74% of animals developed respiratory tract tumors at the dose level of benzo[a]pyrene used. Treatment with BCG cell walls reduced the incidence of respiratory tract tumors to 50%. A similar effect of treatment with BCG cell walls was found when only malignant tumors of the respiratory tract were considered. Both single and multiple injections of BCG cell walls effectively reduced the incidence of respiratory tract tumors.