Figure 2.

PD-1⁺ or CTLA4⁺ T lymphocyte infiltration in different compartments of the tumors of different etiology. The numbers of CD4⁺ and CD8⁺ T lymphocytes expressing the PD-1 molecule in (A) the parenchyma and (B) the stroma, and the numbers of CD4⁺ and CD8⁺ T lymphocytes producing the CTLA4 molecule in (C) the parenchyma and (D) the stroma were compared between groups. PD-1 expression was significantly higher in both compartments of HPV⁺ tumors, while the CTLA4 production was significantly higher only in the stroma of HPV⁻ tumors. * p ≤ 0.05, ** p ≤ 0.01, Mann–Whitney U test.