Among the 340 GC patients for whom IHC staining was conducted, twenty-one GC patients were randomly selected from the ‘EBV positive’ (7 cases) and ‘EBV negative’ (14 cases) groups to determine PD-1, PD-L1, and PD-L2 mRNA expression by qRT-PCR. The gene discussed is CD274; the disease is gastric cancer.