Furthermore, PD-L1 overexpression has been found in a subtype of gastric cancer associated with the Epstein–Barr virus (EBV) infection, and in cervical cancer associated with the human papillomavirus (HPV) infection, where the enhanced PD-L1 production can also be caused by PD-L1 gene amplification [21,22] or upregulation by EBV-encoded latent membrane protein 1 (LMP1) [23]. This evidence concerns the gene CD274 and gastric cancer.