Comparative analysis of T cell population in local LYMPH node in colon cancer patients by stage

Objective: Primary aim was to make a comparative analysis of T lymphocyte infiltration rate and T cell subset ratios in the tumor-draining lymph nodes in colon cancer patients. Secondary aim was to determine the relationship between frequencies of T cell subgroups and stage, KRAS mutation, MSI status and other prognostic factors. Method: Mononuclear cells isolated from the primary tumor-draining lymph nodes of patients who underwent colon cancer surgery in Antalya Education and Research Hospital were stored in liquid nitrogen. At the end of recruitment, cells were thawed and relative ratios of naive T cells, CTL, Th1, Th2, TREG, γδ T cells, Th17, memory cells, and CTLA4, PD1, CCR4 expression rates were calculated by flow cytometric immune phenotyping. Results: Thirty-six patients (%41 female, %59 male) were included in the study. The mean age of the study population was 63.14±11.94 years. Thirteen patients had early stage, 13 patients had locally advanced disease, and 10 patients were in metastatic stage. KRAS mutation rate was 22%. No significant difference was observed in Th1 and Th2 cell ratios according to stage. Th17 cells were increased in correlation with increasing stage. While the immunosuppressive Th2 ratio decreased in the MSI-H subgroup, the TREG ratios increased significantly. No difference was observed in γδ T, Th, CTL, TREG, naive T cells and memory T cells according to the stage, and there was no difference in the ratio of γδ T, Th, CTL, naive T and memory T cells according to molecular changes such as MSI and KRAS mutation. Conclusion: The increase in Th17 cells and immune inhibitory receptor PD1 levels with stage suggests that cells and molecules that suppress the immune response rather than effector cells play a more effective role in determining the invasion status and stage. Key words: colon cancer, T-cell immune response