Different expression patterns of PD-1 in CTLs in ICC tumors. a Representative multiplex immunofluorescence staining to reveal different expression level of PD1 on both CD8 in tumor tissues (T) and peri-tumor tissues (P): red arrows (CD8+ PD-1High); yellow arrows (CD8+ PD-1Low). Scale bar, 50 μm. High expression and low expression in CTLs in tumor tissue were observed by double color staining.
b Quantitative comparisons analysis of CD8+ PD-1High cells and CD8+ PD-1Low cells in between the paired tumor tissues (T) and peri-tumor tissues (P) (Wilcoxon signed-rank test)