Epstein-Barr virus-associated gastric cancer: A distinct subtype.

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is a common malignant tumor associated with EBV infection. The molecular classification of gastric carcinoma indicates that EBVaGC is a distinct subtype in terms of oncogenesis and molecular features. Viral proteins, Bam-HI-A rightward transcripts (BART) miRNAs, and Bam-HI A rightward frame 1 (BARF1) promote oncogenesis after EBV infection via the induction of methylation, regulation of host gene expression, and malignant transformation. Together with abnormal mutations and amplification of the host genome as driving factors, interactions between the EBV genome and host genome accelerate carcinogenesis. The molecular profile of EBVaGC is that of EBV driving DNA hypermethylation, frequent phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) mutations, and the overexpression of Janus kinase 2 (JAK2), programmed death ligand-1 (PD-L1), and PD-L2. Clinically, the frequency of lymph node metastasis is lower, and the prognosis is better for EBVaGC than EBV-negative gastric cancer (EBVnGC). Pathologically, EBVaGC is a gastric adenocarcinoma with lymphoid stroma. This review interprets how the EBV genome is involved in the oncogenesis of gastric cancer and describes the molecular and clinicopathological features of EBVaGC.