CD8A and cancer: Although the infiltration of cytotoxic CD8 + T cells into the stromal component was observed in both non-D-positive and D-positive cases (Fig. 4a, red arrows), in the non-D-positive cases, large numbers of cytotoxic CD8 + T cells were clustered together in a location away from the cancer cells and small numbers were present in the stroma adjacent to the cancer cells (Fig. 4a upper panel), whereas, in the D-positive cases, most cytotoxic CD8 + T cells continuously infiltrated from the adjacent stroma to the inside of the cancer tissue (Fig. 4a, green arrows in lower panel).