CD4+ CD25+ regulatory T-cells role in tumor microenvironment of the squamous cell carcinoma

Squamous cell carcinoma (SCC) is the most common skin cancer with a high rate of death. Different lymphocyte populations play an important role in modulating the immune response in the tumor microenvironment. The increase in the proportion of cluster of differentiation (CD)4+ CD25+ regulatory T-cell (Treg) lymphocytes is associated, in different studies, with the increase of the cell multiplication rate.

To analyze the Treg lymphocyte subpopulations and to correlate the results with the presence of the CD8+ cytotoxic T-cell (Tc) lymphocyte population.

Sixty primary skin SCC specimens were incubated with anti-CD8 (clone SP57) rabbit monoclonal antibody and anti-CD25 (clone 4C9) mouse monoclonal antibody.

The ratio of the intratumoral∕peritumoral CD4+ CD25+ forkhead box protein p3 (Foxp3) lymphocytes was 0.46, emphasizing that at tumor margins, where tumor aggressiveness is higher, these lymphocytes subpopulations facilitate tumor progression. The comparative analysis of the tumor microenvironment profile revealed that in the case of intratumoral immune response, the number of Tc-type lymphocytes (CD8+) was 3.34 times higher compared to Treg lymphocytes (p<0001). In the peritumoral area, the number of Tc lymphocytes was 5.05 times higher compared to Treg lymphocytes (p<0001).

Treg lymphocytes inhibition may cause the suppression of the antitumoral cell immune response in the tumor environment. We believe that Treg lymphocytes should represent a focus of interest for a new personalized therapy. New studies are needed to better understand the immune response in the tumor microenvironment.