Towards a genetic definition of cancer associated inflammation: role of the IDO pathway.
Chronic inflammation drives the development of many cancers, but a genetic definition of what constitutes 'cancer associated' inflammation has not been determined. Recently, a mouse genetic study revealed a critical role for the immune escape mediator indoleamine 2,3 dioxygenase (IDO) in supporting inflammatory skin carcinogenesis. IDO is generally regarded as being immunosuppressive; however, there was no discernable difference in generalized inflammatory processes in IDO null mice under conditions where tumor development was significantly suppressed, implicating IDO as key to establishing the pathogenic state of 'cancer associated' inflammation. Here we review recent findings and their potential implications to understanding the relationship between immune escape and inflammation in cancer. Briefly, we propose that genetic pathways of immune escape in cancer are synonymous with pathways that define 'cancer associated' inflammation and that these processes may be identical rather than distinct, as generally presumed, in terms of their genetic definition.
The American journal of pathology