| Nasopharyngeal carcinoma (NPC) is a common cancer in Southern China. WHO estimates that NPC cases are much higher in China, being 80% of cases of the world. The etiology study of NPC indicated that the development of the NPC is a process with multi-factors and multi-stages. Heredity and environment are related to development of NPC, however, It was reported that infection of Epstein-Barr virus (EBV) is one of the major factors that activate malignant transformation of the nasopharyngeal epithelial cells. But the mechanism of reaction between EBV and NPC is not clear yet. It was believed that EBV of NPC exists in infectious status II, but with the development of molecular biology, recently studies showed that lytic cycle was likely appeared in EBV patients with static NPC cells. However, this has not been elucidated yet. Besides, there has been dispute over whether EBV induces NPC or accompanies NPC. Finally, it is unknown which gene of EBV is involved in the development of NPC. Although EBV appears in all cells of NPC, one of the EBV genes, latent membrane protein (LMP1) only showed 50%-60% of expression in NPC patients, and EB without LMP1 expression might also induce malignant transformation of thenasopharyngeal epithelial cells, suggesting that other EBV genes might be involved in development of NPC. BamHl-A right frame 1 (BARF1), Located in BamHl-W region of EBV gene, is an early stage gene in lytic cycle. Studies reported that It might have ability to immortalize human or monkey kidney epithelial cells and induce tumors. This gene, however, has been tested that has little effect on inducing B lymphocyte transformation. BARF1 other than LMP1 may be important in inducing malignant transformation in nasopharyngeal epithelial cells since BARF1 showed highly expression in NPC cases, and no expression in lymphoma except for Burkitt's lymphoma. These findings suggest that further study on BARF1 may ascertain the mechanism of EBV in development of NPC.In this study, Carcinoma tissues, adjacent tissues, and normal Nasopharyngeal tissues from 47 patients with nasopharyngeal poorly differentiated squamous cell carcinoma (NPDSCC) prepared simultaneously were tested for the presence of the EBV DNA copies levels using real-time quantitative Polymerase Chain Reaction (PCR) assays. As control, carcinoma tissues were obtained form 21 head and neck carcinoma (HNC) patients, and nasopharyngeal tissues from another 10 healthy subjects for detection of EBV DNA copies. Original culture NPC cells, cell line B95-8 and cell line CNEl were also used as control groups to test their EBV DNA copies levels. Besides, we used in situhybridization for in situ detection of EBV in carcinoma tissues, adjacent tissues, and normal nasopharyngeal tissues of patients with NPDSCC. Furthermore, BARF1 expression levels of carcinoma tissues, adjacent tissues, and normal Nasopharyngeal tissues of NPC patients, as well as healthy nasopharyngeal tissues and other HNC tissues were detected by using nested PCR. Lastly, the relationship between EBV DNA copies and BARF1 of carcinoma tissues, adjacent tissues, and normal nasopharyngeal tissues of NPC patients was identified using rank correlation analysis.The results of this study showed that:1. 80% of nasopharyngeal tissues in chronic nasopharyngitis patients and 72.3% of normal nasopharyngeal tissues of NPC patients (34/47) were positive for EBV DNA with mean copies of 6.7+102/gDNA and 9.8+103/gDNA, respectively. There was no significant difference on infectious rate and infectious level of EBV between these two groups. These results indicate that EBV infection appeared in both NPC and healthy subjects. Using EBER-I in situ hybridization, EBER-I expressive signal was not detected in normal nasopharyngeal epithelial cells of NPC, but found in non-proliferation cells in adjacent tissues and in carcinoma cells of NPC, suggesting that a factor might contribute to the entrance of EBV into nasopharyngeal epithelial cell.2. The means of EBV DNA in carcinoma tissues, adjacent tissu...
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