CD8A and gastric neoplasm: Figure 5A shows the lack of CD8+ T cells in gastric tumors of PBS control mice and in PD-1 Ab-treated mice. The number of CD8+ immunoreactive cells is visibly increased in tumors of PAS-treated mice and mice treated with the combination therapy (Figure 5A). Computer analysis of the YTN tumors stained with the CD8+ antibody show marked increase in CD8+ T-lymphocytes in tumors of PAS-treated mice and even a significantly greater increase of CD8+ T cells in mice treated with the combination therapy (Figure 5B).