Role of Inflammation in Metastatic Progression

A link between chronic inflammation and cancer has been suspected since the nineteenth century, when Rudolf Virchow first noted that malignant tumors arise at regions of chronic inflammation and contain inflammatory infiltrates [1–5]. However, the sources of inflammation in tumors that are not associated with a chronic inflammation remain incompletely understood. Recently, it became apparent that inflammation can be evoked not only by extrinsic mediators but also by intrinsic mediators (endogenous molecules) (Figure 14.1). For instance, it has been established that necrotic cell death results in the release of molecules normally stored within cells, such as high-mobility group box 1 (HMGB1) and interleukin (IL)-1α, that act as potent inflammatory mediators [6, 7]. Such molecules may responsible for the triggering of tumor-associated inflammation [7].