However, immunotherapy is only effective in a small proportion of gastric cancers and the expression of PD-L1 on tumor cells or tumor-infiltrating immune cells does not accurately predict for the patient’s response to PD-1/PD-L1 inhibitors (Braun, Burke & Van Allen, 2016; Guan et al., 2017; Wang & Wu, 2017; Pardoll, 2012). This evidence concerns the gene CD274 and neoplasm.