Detection of Epstein-Barr virus in esophageal squamous cell carcinoma in Taiwan

OBJECTIVE: Recently, an association between viral infection and the development of esophageal carcinoma has been reported, particularly the human papilloma virus (HPV) and Epstein-Barr virus (EBV). However, geographic variation in carcinogenesis is realized. In this study, we investigate the viral carcinogenesis and the biologic effect of viral infection on esophageal squamous cell carcinoma (ESCC) in Taiwan. METHODS: To determine the association of viral infection (EBV and HPV) with ESCC, we applied polymerase chain reaction (PCR), immunohistochemistry, and in situ hybridization (ISH) to examine 119 surgical specimens from different sites of esophagus in 31 ESCC patients. Additionally, an immunoperoxidase method was used to detect EBV latent membrane protein-1 (LMP-1), p53, CD45RO (UCHL-1), Fas ligand (Fas L), and RNA ISH with oligonucleotide sequences was used to detected interleukin-6 (IL-6) mRNA. RESULTS: By PCR, EBV DNA was detected in 11 cases (35.5%). Expression of EBERs in ESCC was further confirmed with ISH. Nonetheless, no LMP-1 expression was detected. On the other hand, human papillomavirus (HPV) was identified in only one case (3.2%) of ESCC. Furthermore, HPV was located by ISH in the distant normal region rather than in tumor cells. In EBV-positive cases, accumulation of p53 protein was detected in 10 lesions (91%); CD45RO⁺ lymphocytes together with expressions of FasL and IL-6 were respectively identified in 100%, 63.6%, and 54.5% of 11 EBV-positive lesions. Interestingly, in the EBV-negative cases (n = 20), p53 protein was detected in 40% of lesions; CD45RO 30%; FasL 50%, and IL-6 10%. CONCLUSIONS: In this study, no correlation was found between the presence of EBV in ESCC and the patients' age, sex, as well as survival. Although our results indicate that EBV could be associated with ESCC, the clinical role of EBV in ESCC remains to be determined.