CD274 and gastric cancer: The amplification rate of the HER2 gene and the expression of PD-1/PD-L1 were not related to the sex and age of patients (P > 0.05); the amplification rate of the HER2 gene and the expression of PD-1/PD-L1 were related to the depth of invasion and lymph node metastasis of gastric cancer, with significant differences (P < 0.05), as shown in Table 2.