Fig. 2

A Patients were classified into four groups (I–IV) based on programmed death ligand-1 (PD-L1) expression in tumor cells and CD8⁺ cell counts at the tumor invasive front. B Kaplan–Meier plots of relapse-free survival in the subgroups. The differences in survival between groups I (high PD-L1 expression and high density of CD8⁺ cells) and IV (low PD-L1 expression and high density of CD8⁺ cells) were statistically significant (P = 0.015). C Box-and-whisker diagrams present fluoro-d-glucose (FDG) uptake in the four subgroups. Group II (low PD-L1 expression and low density of CD8⁺ cells) had significantly lower FDG uptake (indicated by the maximum standardized uptake value (SUVmax)] than the other groups (P = 0.043). D The density of CD15⁺ cells at the tumor invasive front was not significantly different among the four groups, but comparing groups I and IV, both of which had high CD8⁺ cell counts despite having high and low PD-L1 expression, respectively, group IV tended to have a higher density of CD15⁺ cells than group I (D)