Immune Suppression and Colorectal Cancer

Immune Suppression

Patients with colorectal cancer are likely to be immunosuppressed due to a number of factors including old age^[36] and nutritional status.^[37] However, colorectal cancer itself has a direct immunosuppressive effect as demonstrated by studies showing resolution of normal immunological function after successful tumour resection.^[38,39] The immune suppression occurs at both a molecular and cellular level with tumour immune tolerance starting gradually and locally, then progressing and finally spreading to the whole organism^[40] (see Figure 1 for overview).

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Potential mechanisms of immune suppression caused by tumour cells. IL, interleukin; TGF, transforming growth factor; COX, cyclo-oxygenase; VEGF, vascular endothelial growth factor; TNF, tumour necrosis factor; NO, nitric oxide; Treg, regulatory T; NK, natural killer; DC, dendritic cell; IFN, interferon; TNF, tumour necrosis factor.

Aliment Pharmacol Ther. 2006;24(8):1163-1177. © 2006  Blackwell Publishing