CD8A and gastric cancer: TCGA RNA-seq gene expression profiling revealed a decrease in the CD8+ T-cell marker gene (CD8A), NK cell marker genes (KLRC1 and KLRF1), T-cell cytolytic activity genes (GZMA and PRF1) in p53-mutated gastric cancers when compared to wild-type p53 gastric cancers (Jiang et al., 2018).