To examine the activation level of these CD8+ T-cells that co-expressed PD-1 and CD137, we measured the IFN-γ production of these tumor infiltrating CD8 + PD-1 + CD137+ T-cells after isolating CD8+ T-cells and incubating them with CD3/CD28 stimulation beads, and then performed flow cytometry analysis for CD137, PD-1 and IFN-γ expression amongst these CD8+ T-cells. This evidence concerns the gene CD28 and neoplasm.