The inflammatory tumor microenvironment and its impact on cancer development.

The role of the immune system during cancer development is complex involving extensive reciprocal interactions between genetically altered cells, adaptive and innate immune cells, their soluble mediators and structural components present in the neoplastic microenvironment. Each stage of cancer development is regulated uniquely by the immune system; whereas full activation of adaptive immune cells at the tumor stage may result in eradication of malignant cells, chronic activation of innate immune cells at sites of premalignant growth may actually enhance tumor development. In addition, the balance between desirable antitumor immune responses and undesirable pro-tumor chronic inflammatory responses largely depends on the context in which a malignancy is developing. The following chapter focuses on the inflammatory components and processes engaged during cancer development and the impact of the inflammatory microenvironment.