Pathologic Studies of Epstein-Barr Virus (EBV) and Its Gene Expression in Nasopharyngeal Carcinoma (NPC)

• Main Authors: Chen, Chi-Long, 陳志榮
• Other Authors: Hsu, Hey-Chi
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/14329385983303889860

博士 === 國立臺灣大學 === 病理學研究所 === 81 === Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies in Taiwan. The pathogenesis of NPC remains unclear. Epastein-Barr virus (EBV) is the most important contributing factor of NPC. In order to better understand the role of EBV in pathogenesis of NPC, we have attempted to char- acterize viral infection and identify the viral genes expressed in 60 cases of NPC. The results showed EBV genome is only present in the tumor cells of NPC but not the infiltrating lymphocytes. The tumor was clonal expansion from one EBV-containing cells and had episomal form EBV DNA and most of them also had linear form DNA, indica- ting presence of latent EBV in all NPC, and with viral replica- tion in most cases. The EBV typing study revealed EBV-1 only. The EBV gene expression was studied in 10 cases of NPC by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization. Six EBV latent genes and the immediate early gene-BamHI Z leftward frame 1 (BZLF1) were checked. An An other EBV latent small RNA, EBER1, was detected in 48 NPC cases by in situ hybridization. The results revealed all NPCs had EBNA1 and LMP2A, LMP1 and BZLF1 were detected in 8 cases each, LMP2B in 6 cases, and BARF0 in 9 cases. Three cases had trace amount of EBNA2 message. All studied NPC cases containing EBER1 message in tumor cells and the infiltrating lymphocytes were consistently negative. The EBV-related antigens was detected by immunocytochemistry using different antibodies. The results showed only 21 cases (36.2%) of 58 NPCs were LMP1 protein positive. The other EBV- related antigens were all negative. The staining pattern of LMP1 in NPC tumor cells was diffusely distributed in cytoplasm with no cytoplasmic aggregate as seen in lymphoblastoid cells.