Cytokines (IFNs, TNF-alpha, IL-2 and IL-12) and animal models of cancer.

Cytokines are a complex family of mediators that influence many aspects of tumour cell biology. Whether they are used as a therapy or produced locally during the process of tumorigenesis, they are able to act on tumour cells, on the tumour stroma and on the host itself. Animal models have played key roles in optimizing doses and schedules, and have been useful in determining net effects in the tissue microenvironment. Whilst early studies used xenogeneic and syngeneic systems, more recently gene and protein delivery systems have been used to introduce ectopically expressed high and continuous levels of cytokines. This review will discuss the application of some animal model systems that have been investigated to further understand the role cytokines play in cancer, and will concentrate on those cytokines for which there are the most experimental animal model data.