EBV-Associated Gastric Cancer
Gastric cancer and nasopharyngeal carcinoma are the only two epithelial tumors known to be associated with Epstein-Barr virus (EBV) infection. However, in contrast to near universal involvement in nasopharyngeal carcinoma, only 8-10 percent of gastric cancers are positive for EBV. Despite differences in primary etiology of cancers of the upper (cardia) and lower (noncardia) stomach, EBV-positive tumors occur at both of these anatomic subsites. To date, most studies that have evaluated EBV-associated gastric cancer have been modest in size, and it is unclear whether co-factors associated with these cancers differ from those associated with the more common EBV-negative tumors. To study this scientifically important subgroup efficiently, DCEG leads the NCI-International EBV-Gastric Cancer Consortium, a research collaboration pooling data and biospecimens from 18 completed and ongoing observational studies of gastric cancer. Consortium projects have included comparisons of tumor characteristics, antiviral antibodies and markers of inflammation in patients with EBV-positive vs. -negative gastric cancer. Ongoing efforts are examining additional biomarkers such as circulating cell-free DNA methylation and viral as well as human-encoded microRNA. Collaborative work with The Cancer Genome Atlas has helped to establish EBV-positive gastric cancer as a distinct molecular subtype of gastrointestinal tract adenocarcinoma.