It was found that the mean percentages of CD8+ T and CD8+ Tm expressing PD-1 as well as PD-1+CD8+T/PD-1+CD4+T cell ratio were significantly higher in responder (R) than non-responder (NonR) advanced gastric cancer patients associated with a longer progression free survival (PFS) and overall survival (OS). Here, CD8A is linked to gastric cancer.