CD8A and cancer: The expression levels of CD137 and CD160 on CD8+ T cells from esophageal cancer patients were significantly higher than that from normal donors (cancer patients vs. healthy donors, 10.12 ± 2.571% vs. 3.122 ± 0.4173%, p = 0.0150; 48.26 ± 5.225% vs. 33.95 ± 3.807%, p = 0.0400, Figure 2).