To investigate the mechanism which downregulates TET2 expression during EBV infection, we first examined if EBV encoded transcripts contribute to decrease of TET2. It is known that most of EBV genome is dense methylated in latent infection in gastric epithelial cells, and the limited number of protein-coding genes, LMP2A and EBNA1, and non-coding transcripts, BARF0 and EBER1/2, are allowed to express [5, 23]. The gene discussed is TET2; the disease is Epstein-Barr virus infection.