The 9L rat brain tumor: description and application of an animal model.

Animal models allow determination of tumor response to anticancer agents under various experimental conditions. The chemically induced 9L rat brian tumor has been developed as both in vivo and in vitro models. Animal survival, clonogenic cell survival, and tumor growth delay provide means to measure the effectiveness of treatment modalities in this tumor model. Monolayer cultures, multicellular spheroid cultures, brain tumors, and flank tumors have been used to study the influence of different biological entities of the 9L model on the response to treatment with radiation and/or BCNU (1,3-bis (2-chloroethyl)-1-nitrosourea).