Cross-species chromatin interactions drive transcriptional rewiring in Epstein–Barr virus–positive gastric adenocarcinoma

Epstein–Barr virus (EBV) is associated with several human malignancies including 8–10% of gastric cancers (GCs). Genome-wide analysis of 3D chromatin topologies across GC lines, primary tissue and normal gastric samples revealed chromatin domains specific to EBV-positive GC, exhibiting heterochromatin-to-euchromatin transitions and long-range human–viral interactions with non-integrated EBV episomes. EBV infection in vitro suffices to remodel chromatin topology and function at EBV-interacting host genomic loci, converting H3K9me3+ heterochromatin to H3K4me1+/H3K27ac+ bivalency and unleashing latent enhancers to engage and activate nearby GC-related genes (for example TGFBR2 and MZT1). Higher-order epigenotypes of EBV-positive GC thus signify a novel oncogenic paradigm whereby non-integrative viral genomes can directly alter host epigenetic landscapes (‘enhancer infestation’), facilitating proto-oncogene activation and tumorigenesis. Genome-wide analysis of 3D chromatin topologies across gastric cancers suggests that Epstein–Barr virus infection may induce the epigenetic rewiring of EBV-positive tumors through human–viral chromatin interactions, a phenomenon termed ‘enhancer infestation’.