EVALUATION OF EPSTEIN-BARR-VIRUS INFECTION IN HYPOPHARYNGEAL CARCINOMAS FROM 37 JAPANESE PATIENTS

Thirty-seven biopsy specimens from primary sites, 18 surgically remove d metastatic neck nodes, and 18 surgically removed primary sites from 37 patients with hypopharyngeal carcinoma (HPC) were evaluated for the presence of Epstein-Barr Virus (EBV) infection by irt situ hybridizat ion (ISH) and polymerase chain reaction (PCR). Although some of normal lymphocytes in 6 of 18 metastatic nodes were positive by ISH, there w ere no positive results from HPC tumor cells themselves. Our results i ndicate that EBV-infected non-neoplastic cells such as lymphocytes can be a cause of false positivity, if a study were conducted with PCR al one. Because ISH for EBV-encoded early RNAs was highly sensitive, even more sensitive than PCR from paraffin-embedded samples in our study, this method should be the first choice for identification of EBV infec tion to avoid false positives.