Expression of Epstein-Barr virus in mesopharyngeal and hypopharyngeal carcinomas

Epstein-Barr virus (EBV) causes various tumors, including nasopharyngeal ca rcinoma (NPC). There have been no reports as to whether the carcinogenicity of EBV is restricted to the nasopharynx or extends into the mesopharynx an d hypopharynx. We attempted to ascertain the relation between EBV and mesop haryngeal (MPC) and hypopharyngeal carcinomas (HPC), Messenger RNA in situ hybridization showed that all 29 cases of MPC and 5 of 12 HPC expressed EBV mRNA, For further analysis, we established 7 cell lines from 5 MPC and 2 H PC. All cell lines and 5 tumors formed by these cultured cells in nude mice expressed EBV transcripts. Moreover immunofluorescence staining showed exp ression of EBV-related nuclear antigen-2 and latent membrane protein-1 (LMP 1) in the original tumors and the cell lines, as well as in nude mouse tame rs. Study by reverse transcription polymerase chain reaction (RT-PCR) also showed EBER1 and LMP1 expression. Furthermore, lytic-cycle antigens of EBV were detectable in most cell lines. Nested PCR showed the EBV genome in 3 c ases of MPC and 4 cases of HPC. These results suggest that EBV plays an imp ortant role in the development of MPC and HPC as well as in NPC. HUM PATHOL 30:1071-1076, Copyright (C) 1999 by W.B. Saunders Company.