Presence of Epstein-Barr virus in esophageal cancer is restricted to tumor infiltrating lymphocytes

As representatives of low and high incidence countries respectively, 72 esophageal squamous cell carcinomas and 40 adenocarcinomas from Germany, and 43 esophageal squamous cell carcinomas from Russia were tested for the presence of Epstein-Barr virus (EBV) DNA by PCR and in situ hybridization. Thirty four percent of the squamous cell carcinomas (SCC) and 26% of the adenocarcinomas (AC) contained EBV DNA as detected by nested PCR. Quantitative analysis using real time PCR revealed one copy of the EBV genome per every 27-200,000 cells. EBER RNA in situ hybridization showed no EBV-specific transcripts in the nuclei of the tumor cells. However, EBER transcripts were expressed in the nuclei of tumor infiltrating lymphocytes in 7 SCC and I AC of 24 EBV DNA positive cases. The present data provide no evidence for the persistence of EBV in the tumor cells of esophageal cancer. In contrast to a previous report from Taiwan, EBV is unlikely to play a role in esophageal carcinogenesis.