[Expression of Epstein-Barr virus in mesopharyngeal and hypopharyngeal as well as nasopharyngeal carcinomas].

Epstein-Barr virus (EBV) is known to cause nasopharyngeal carcinoma (NPC). However, this carcinogenicity of EBV is restricted in nasopharynx or extended into mesopharynx and hypopharynx has not been studied. Messenger RNA in situ hybridization showed that all mesopharyngeal carcinomas (MPC) and 40% of hypopharyngeal carcinomas (HPC) tested expressed EBV mRNA. Established cell lines and tumors generated in nude mice also showed EBV expression. Further, immunofluorescence staining by monoclonal anti-EBV nuclear antigen-2, latent membrane protein-1, viral capsid antigen and early antigen were also positively stained. These results suggest that EBV expresses in most MPC and HPC, and that EBV plays an important role in the development of MPC and HPC as well as NPC.