Do autochthonous tumors interfere with effector T cell responses?

The assumption that autochthonous tumors interfere with the effector T cell (T-E) response implies that they first induce functional T cells. However, if T-E are generated, they usually remain functional, persist life-long as memory cells and prevent tumors. This holds true for some virus-induced tumors and is associated with evolutionary pressure. In contrast, models that allow monitoring of tumor antigen-specific T cells suggest that spontaneous autochthonous tumors either sneak through or induce TE too late when the tumor has developed resistance to T-E or induce tolerance. This can be explained by the absence of evolutionary pressure. (c) 2007 Elsevier Ltd. All rights reserved.