Expression and prognostic roles of PIK3CA, JAK2, PD-L1, and PD-L2 in Epstein-Barr virus–associated gastric carcinoma

Summary As a special subtype of gastric carcinoma, Epstein-Barr virus (EBV)–associated gastric carcinoma (EBVaGC) has distinct clinicopathological features. The Cancer Genome Atlas Research Network revealed that EBVaGC also has distinct molecular features: PIK3CA mutations, DNA hypermethylation, and JAK2 , PD-L1 , and PD-L2 amplification. Here, we evaluated PIK3CA, JAK2, PD-L1, and PD-L2 expression in 59 EBVaGC and 796 EBV-negative gastric carcinoma (EBVnGC) cases using immunohistochemistry and found that PIK3CA, JAK2, PD-L1, and PD-L2 were highly expressed in 75.9% and 48.8% ( P P =.091), 92.5% and 84.8% ( P =.132), and 98.1% and 89.7% ( P =.049) of the EBVaGC and EBVnGC cases, respectively. However, the expression of PIK3CA, JAK2, PD-L1, or PD-L2 was not significantly associated with clinicopathological features or patient outcomes in EBVaGC. In contrast, in EBVnGC, high PIK3CA expression was significantly associated with indolent clinicopathological features and independently predicted better 5-year overall survival (57.8% versus 33.4%, P