Epstein-Barr virus (EBV)-associated gastric carcinoma (GC), comprising nearly 10% of all cases of GC, is the monoclonal growth of EBV-infected epithelial cells, which express a limited number of EBV-latent genes(latency I program). The primary molecular abnormality in EBV-associated GC is the epigenetic abnormality, that is, global CpG island methylation in the promoter region of many cancer-related genes. Experimental infection of EBV induced this EBV-specific epigenotype in addition to gastric cancer epigenotype in gastric cancer cells. Viral latent membrane protein 2A (LMP2A) is partly responsible for the promotion of DNA methylation, through STAT3-mediated up-regulation of DNMT1. Such a mechanism may be the overdrive of interaction between virus and infected cells.