Investigation of the interaction of HLA-G with natural killer Surface Marker kir in Kolorectal cancer

Immunity is an organized system that defends the host against external and internal threats. Tumour cells can carry some surface antigens unlike normal cells and they can be perceived as 'unfamiliar' cells, therefore this antigens might cause an immune responce. Most cancer cells don't express or reduce the expression of surface antigens to escape immunity, therefore they are not eliminated by the host. An efficiant immune surveillance requires surface antigens along with the expression of human leukocyte antigen (HLA). The differences of HLA antigens in tumor cells have been suggested as a mechanism that causes tumor cells to escape from natural killer (NK) cells. Colorectal cancer can cause poor prognosis and numerous changes in individual's immune system like the increasement of HLA antigens in cell surface, the deterioration of NK cell function and escape from the immunity. In our study, we aimed to determine soluble HLA-G (sHLA-G) antigens by ELISA method from peripheral blood serum samples, to investigate the loss or absence of HLA-G expression in tumor tissue through immunohistochemistry (IHC) and the infiltration of KIR (killer-cell immunoglobulin- like receptor) indicators on NK cell surface to the tumour tissue. As a result of this study, it was observed that the expression of HLA-G and KIR markers in patients with CRC increased and it might be a strong, independent and useful prognostic marker in CRC. We did not observe any difference between sHLA-G levels. Our results suggest that HLA-G and KIR markers may be a promising target for future immunotherapeutic approaches.