Significance of experimental models in neurooncology.

Three models are induced for the production of brain tumors: Carcinogenic viruses, topically applied carcinogenic hydrocarbons and so-called resorptive carcinogens, mostly alkylating substances. The usefulness of these models for questions in human neurooncology depends upon similarity relation between model and original, i.e. the human brain tumor, both regarding the induction mode and the morphological result. In the last years the model with resorptive carcinogens has been broadly used. This model is suitable for questions concerning the mechanisms of action of carcinogenic substances and the formal pathogenesis of brain tumors. It seems less appropriate for other investigations: The growth behavior and its possible influence may be better studied with standardized tumor models. Such derived models are described in this paper and their usefulness for investigations especially concerning the chemotherapy of brain tumors is discussed.