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).
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
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