Dendritic cells integrate signals from the tumor microenvironment to modulate immunity and tumor growth

Dendritic cells (DCs) are professional antigen presenting cells with the ability to either initiate or prevent the induction of antigen-specific T cell responses. The conventional DC-centric paradigm of DC-T cell interactions emphasizes the induction of T cell tolerance by immature DCs and the induction of T cell immunity by mature DCs. However, current evidence suggests that DCs can exist in a multitude of functional states other than simply immature or mature and the immunogenic capacity of the DC may be conditioned by the microenvironment. It is likely that DCs are important for the induction of tumor immune surveillance or promoting immune evasion. In this review, we have highlighted how signal transducer and activator of transcription 3 (Stat3) hyperactivation and inflammatory mediators associated with chronic inflammation can disarm DCs and subvert protective immune surveillance of cancers. (C) 2009 Elsevier B.V. All rights reserved.