Comparative analysis of some immunological parameters depending on the tumor location on the right and left sides of colon
Authors: Kit O. I. , Dzhenkova E. A. , Mirzoyan E. A. , Sagakyants A. B. , Zlatnik E. Yu. , Bondarenko E. S. , Novikova I. A. , Maslov A. A. 
Published: September 2022

Background: Colorectal cancer is now an urgent problem in oncology. Recently, specialists have been interested in a comparative analysis of differences in the clinical course of malignant tumors in the proximal and distal colon. The sections differ not only in their embryogenesis and sources of blood supply, but also in the clinical course and population and epidemiological characteristics. The issue of distinctive immunological characteristics of tumors of the colon depending on the location remains open.

Objective: A comparative analysis of local subpopulations of immunocompetent cells and an assessment of number of cells with the CD45+/- phenotype expressing toll-like receptors (TLRs) depending on the tumor location on the right or left sides of the colon.

Material and methods: The study included 50 patients with verified colon cancer. The majority of patients were females – 26 (52%), aged 67 ± 0.4 years, and 50% of patients with stage II disease. Depending on the tumor location (the right or left sides of the colon), the patients were divided into 2 groups of 25 people each. All patients underwent standard surgery at the initial stage. The obtained material was used for subsequent studies: a cell suspension was obtained from a tumor tissue fragment, the perifocal zone (1–3 cm from the tumor) which was processed using an antibody panel (Becton Dickinson, USA) to identify the main subpopulations of leukocytes and lymphocytes. Expression of TLRs (2, 3, 4, 8, 9) on CD45+, CD45- cell populations was also determined using the BD FACSCanto flow cytometer (Becton Dickinson, USA). Statistical processing of the results was performed using the STATISTICA 13.3 package (StatSoft Inc., USA).

Results: A comparative analysis of immunological parameters, depending on the tumor location on the right or left sides of the colon, showed:

Tissues of the right-sided tumors had a higher T-lymphocytic infiltration, compared to the left-sided tumors, while the latter showed a higher B-lymphocytic infiltration (p = 0.025).

Peritumoral zone tissues of left-sided tumors demonstrated a decrease of lymphocytes levels (p = 0.027), NKT – (p = 0.035), NK – (p = 0.041) and В lymphocytes (p = 0.038), and a significant increase in CD8+- (p = 0.02) and DP cells (p = 0.0018).

Left-sided tumors showed a percentage decrease of CD45- cells expressing TLR4 and TLR8, compared to right-sided tumors, by 38% (p = 0.038) and 25% (p = 0.043).

There was a decrease in the number of CD45+ cells expressing TLR2 and TLR4 in left-sided tumors by 54% (p = 0.035) and 33% (p = 0.04) respectively, than in right-sided tumors.

The percent of CD45- cells expressing TLR4 in the perifocal tissues of left-sided tumors decreased by 61% (p = 0.031) in comparison to the corresponding tissues in right-sided tumors.

The numbers of CD45+ cells expressing TLR2 and TLR4 were 81% (p = 0.02) and 87% (p = 0.018) lower respectively in the peritumoral tissues of left-sided tumors, compared to the corresponding tissues in right-sided tumors.

Conclusion: The revealed characteristics of the local subpopulations of immunocompetent cells and the numbers of CD45+/- cells expressing TLRs depending on the tumor location on the right or left sides of the colon can serve as a prognosis of the disease clinical course and the choice of further treatment tactics.