ABSTRACT
The Epstein-Barr Virus [EBV] belongs to the genus lymphocrypto-virus and subfamily gamma-herpesvirinae. This virus infects the lymphocytes of primates and causes a latent infection in the B lymphocytes of these animals in vitro and in vivo. It also infects epithelial cells which are permissive for virus replication. A correlation between infection with EBV and Burkitt's lymphoma and nasopharyngeal carcinoma has long been known to exist, although the role of the virus in these cancers is not well understood. A less clear correlation between infection and other cancers, including cancer of the esophagus, has also been reported. Given the high incidence of cancer of the esophagus in Iran, we set out to study the level of infection with this virus in Iranians afflicted with the cancer. For detection of the virus, we performed half-nested PCR reactions using primers complementary to a well preserved region of the EBV virus genome. DNA extracted from LCLPI 4 cells, which is a B lymphocyte cell line infected with EBV, acted as positive control. The length of the product of first PCR reaction was 168 bp and of the second reaction 121 bp, which are the expected lengths. Our samples were DNA extracted from mounted tissue sections of the esophagus or unmounted sections cut from paraffin blocks. Both types of samples were obtained from the archives of the pathology department of a national hospital. Thirty-four squamous cell carcinoma, 8 adenocarcinoma and 29 esophagitis samples were tested. DNA from 28,7 and 26, respectively, of these sample groups, corresponding with 86% of all the samples, served effectively as template in the PCR reactions. Twelve [42.8%], 3[42.8%] and 11[42.3%] of the effective squamous cell carcinoma, adenocarcinoma, and esophagitis samples, respectively, were EBV positive as established by the PCR technique. Only one of eleven normal esophageal sections was positive [9.1%]. Tentatively, there appears to be a correlation between EBV infection of esophageal tissue and abnormalities of the esophagus