CD274 and neoplasm: Given that high PD-L1 expression is closely associated with EBV+ and MSI-H GC, PD-L1 may also be expressed through adaptive immune resistance, which occurs due to the many cytotoxic T-cells and neoantigens present within tumor cells (secondary to EBV itself and the many frameshift mutations seen in EBV+ and MSI-H cancers) and is associated with favorable prognosis.