Inflammatory biomarkers for cancer

Abstract

Cancer is associated with various degrees of inflammation both locally and systemically, resulting from an immunological response towards malignant lesions. Here, we critically evaluate several inflammatory parameters as biomarkers and prognostic tools for cancer. Colorectal cancer (CRC) represents a paradigm of the causative relationship between chronic inflammatory disease and cancer development. However, close examination reveals that for CRC, risk in patients with inflammatory bowel disease (IBD) has been largely overestimated. In fact, IBD patients only have a slightly increased risk of developing CRC (standardized incidence ratio ~ 1.7), which only weakly supports the link between chronic inflammation and cancer. However, long-term immunosuppressive treatment of IBD patients is associated with an increased risk for overall cancer, particularly haematologic and skin cancers. In contrast, there is a strong association between infection with the bacterium Helicobacter pylori, gastritis, and gastric cancer. Therefore, H. pylori seropositivity or the associated gastritis may be used as predictive biomarkers for cancer, although the rate of false positives is high. We have also reviewed several cytokines of the interleukin-1 family and cytokines that converge on STAT3 signalling because they are very well suited to illustrate the multitude of cytokine actions that makes interpretation of one single cytokine as a biomarker of cancer very complex. In addition, we describe in more detail the biology of IL-33, the most recently identified member of the IL-1 family, because it has not yet been subject to review in the context of cancer immunology.