The Place of Blood Immune Markers in Colon Cancer

(primary vs metastatic tumour). We have shown that the expression of leptin (also considered as a cytokine-like) receptor in colon tumour cells influences chemokine expression depending on the colon location and MMR status. 11 Simultaneous increases in FoxP3, IL17, IL6 and TGFb expression in the majority of sporadic CRC (microsatellite stable (MSS) and leftsided), argue for a disturbed immune response of CRCs and may suggest that IL17 overproduction in these tumours probably leads to exacerbation of the disease. Relative concentrations of IL6 and TGFb in tissues balance the differentiation of coexisting CD4RORct Th-17 cells and regulatory CD4FoxP3RORct IL17-negative T cells, the ratio of which was proposed to play a role in the regulation of immunoreactivity. Taking all these data together, the immune response in CRCs with MSI-H should be considered different from that observed in MMRproficient tumours. Unfortunately, MMR status (routinely assessed by using immunohistochemistry and/or PCR) has not been characterised by Chaput et al, and the level of IL17 in situ expression is not given in this study. Thus, the increase in TGFb1 and IL6 in their series cannot be correlated with the level of IL17 nor with the MMR status. Whether the immune response in tissue is the same regardless of the colon tumour site or metastatic site deserves further investigation. The mode of antigen presentation may contribute to the induction of tumourassociated antigen (TAA)-specific T cells with impact on T effector cells. A positive correlation between the number of antigen-presenting cells (APCs) and Foxp3 T cells and an inverse relationship with the systemic TAA T cell response has been reported. Therefore, it would also be of great interest to investigate the tumourinfiltrating myloid-derived suppressor cells with special reference to MMR status. 3