The density of CD8+ T cells (CD8+ density), the density of CD8+Ki67+ T cells (CD8+Ki67+ density) T cells and the Ki67 labeling index of CD8+ cytotoxic T cells/percentage of Ki67+ proliferating CD8+ cytotoxic T lymphocyte (CD8+Ki67+ proliferation rate) were successfully analyzed in a total of 1107 of 1475 (75%) colorectal, 1066 of 1566 (68%) breast, 642 of 1809 (36%) renal cell, 375 of 608 (62%) ovarian, 451 of 599 (75%) pancreatic and 347 of 384 (90%) gastric cancer samples. The gene discussed is CD8A; the disease is gastric cancer.