Introduction

Oncogene (2008) 27, 5868; doi:10.1038/onc.2008.277

Cancer and the immune system: an overview

G E Blair1 and G P Cook2

  1. 1Institute of Molecular and Cellular Biology, University of Leeds, Faculty of Biological Sciences, Leeds, UK
  2. 2Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK

Correspondence: Professor G Eric Blair, Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, Garstang Building, Room 8.52d, University of Leeds, Leeds LS2 9JT, UK. E-mail: g.e.blair@leeds.ac.uk

The roots of cancer immunology lie in the work of some of the most influential immunologists of the last 100 years. The year 2008 sees the centenary of the birth of immunology itself, marked by the award of the Nobel Prize to Elie Metchnikoff and Paul Ehrlich in 1908 (Kaufmann, 2008). Around this time, Ehrlich put forward a hypothesis that the immune system might control tumours. The origins and progress of cancer immunology, and its associated high and low points, has been reviewed in depth, highlighting the development of ideas from Ehrlich and Medawar through to the cancer immunesurveillance hypothesis of Burnet and into the era of cellular and molecular immunology (Dunn et al., 2002). The Oncogene review articles collected here provide a glimpse at how several of the concepts of cancer immunology currently stand.

As all students of immunology should know, the immune system works essentially by discriminating self from non-self. This enables the detection and elimination of the smallest viruses and the largest multicellular parasites. Non-self is discriminated from self by fundamental differences in biochemistry, such as the arrangement of carbohydrate residues on glycoproteins or the absence of methylated cytosine residues in DNA. These differences are detected by the numerous pattern receptors, which are a hallmark of the innate immune system. These pattern receptors include the Toll-like receptors, the subject of a recent Oncogene review issue (O'Neill, 2008). The activation of innate immunity leads to the efficient priming of adaptive immune responses mediated by B and T cells. These cells carry antigen receptors and, through education and cooperation, can distinguish self from non-self antigen and trigger subsequent events. However, tumour cells are self in origin and their biochemistry and behaviour differs only subtly from their healthy counterparts. This requires the detection of altered self.

There is now a substantial body of data to show that innate and acquired immune responses to tumours do exist and that a multitude of immune cell types and their associated molecules are involved in detecting and eliminating tumours, several of which are discussed in the reviews presented here. Immunity to infection and tumour immunity share a common ‘dark side’, that of immune evasion. It is a sad fact that, by the time a patient presents with a clinically detectable tumour, the tumour has already successfully evaded cancer immunesurveillance mechanisms and is living alongside the immune system. Indeed, the immune system places strong selective pressure on tumours (and pathogens). Ultimately, those rare tumour cells that have mutations in the pathways that allow immune detection and elimination are the cells that survive, proliferate and kill the patient, the phenomenon of immunoediting (Teng et al., 2008). The goal behind many immunotherapeutic strategies is to tip the balance from tumour immune evasion to a productive anti-tumour response. Broadly, it has not been our aim to present reviews of immunotherapeutic strategies but to describe the more fundamental interactions between immune system components and tumour cells. However, it is from these basic studies that molecular and cellular targets of immunotherapy emerge and these areas are highlighted in these reviews.

Successful immunotherapy has been demonstrated using antibodies that target cancer cells, the subject of a previous Oncogene review (Bonavida, 2007). Studies of the role of the cellular immune system in controlling cancer cells, such as those described in this Oncogene review issue, promise to deliver not only fascinating insights into the immune system but also lay the foundation for future cellular immunotherapies.

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References

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  2. Dunn GP, Bruce AT, Ikeda H, Old LJ, Schreiber RD. (2002). Cancer immunoediting: from immunosurveillance to tumor escape. Nat Immunol 3: 991–998. | Article | PubMed | ISI | ChemPort |
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