Fig. 4

The expression of immune-cell markers (CD8⁺ and CD68⁺ cells) by immunohistochemistry. A Distribution of cells expressing the cytotoxic T cell marker CD8⁺ per mm² in tumor and non-tumor areas. R represents responders and NR represents non-responders. B The ROC curve based on CD8⁺ cells in the tumor area of each patient. The cut-off score for calculating sensitivity and specificity is indicated by a blue dot. C Distribution of cells expressing the macrophage/microglia marker CD68⁺ per mm² in tumor and non-tumor areas. D (i–ii): Histologic features of the tumor area in responders and non-responders (Hematoxylin and eosin. 1000 × 1000 μm), (iii–iv) The median number of CD3⁺ T cells was not significantly different between responders and non-responders, as a similar density of CD3⁺ T cell infiltration was observed in both groups. (v–vi) The density (number of cells/mm²) of CD8⁺ cytotoxic T cells in the tumor was higher in responders than in non-responders. (vii–viii) The density of CD68⁺ macrophages/microglia in the tumor was higher in responders than in non-responders, and in some areas in responders, increased density of these cells coincided with high CD8⁺ T cell density, which suggests intimate interactions with cytotoxic T cells (gray arrows). In some thick-walled vessels, a high density of immune-cell infiltration was observed (left angle bracket)