The role of inflammation in tumour growth and tumour suppression.

The relationship between inflammation and tumour growth is poorly understood. The quality, quantity and time point of the inflammatory response may decide whether inflammation supports or inhibits tumour growth. Three examples are given that illustrate the different role of inflammation for tumour growth. It will be shown that tumour infiltrating macrophages can contribute to tumour rejection, can be essential for tumour growth or can occur as innocent bystander cells in tumours. Then it will be shown that the timely arrival of T cells at the tumour site is critical for tumour rejection and that non-bone marrow-derived tumour stromal cells are important targets during tumour rejection. Finally, a protective inflammatory response against the chemical carcinogen methylcholanthrene (MCA) will be discussed. This response is related to a tissue repair response induced by the tissue damaging effects of the carcinogen in the course of which MCA is encapsulated and no longer able to induce tumours.