Lin Su-Xia, Zong Yong-Sheng, Wu Qiu-Liang, Han An-Jia, Liang Ying-Jie
Department of Pathology, Cancer Center, Sun Yat-sen University, Guangzhou, PR China.
Ai Zheng. 2003 Nov;22(11):1147-51.
BACKGROUND & OBJECTIVE: It is well known that Epstein-Barr virus(EBV) LMP1 gene is involved in nasopharyngeal carcinogenesis. This research was designed to investigate the loss of an Xho I-site within the N-terminus of Epstein-Barr virus(EBV) latent membrane protein 1(LMP1) gene isolated from nasopharyngeal carcinoma (NPC) in Guangdong for further understanding the sequence variation of LMP1 gene involved in carcinogenesis.
Sixty-three fresh nasopharyngeal biopsies taken from the patients with nasopharyngeal carcinoma were collected in Cancer Center of Sun Yat-sen University. The peripheral blood mononuclear cells (PBMCs) obtained from 10 healthy EBV carriers were as control. The QIAamp DNA Mini Kits were used for extracting the DNA of biopsies and PBMCs. The N-terminus of EBV LMP1 gene was amplified using nested polymerase chain reaction (PCR) and then followed by Xho I enzyme digestion. Bidirectional solid-phase sequencing of the PCR products was performed using four-colored fluorescence terminator sequencing method.
No loss of an Xho I-site within N-terminus of EBV LMP1 gene (wt-Xho I) was detected in PBMCs of all 10 carriers. The loss of an Xho I-site (Xho I-loss) was demonstrated in 50 cases (50/63, 79.36%) and the partial loss was demonstrated in 4 cases (4/63, 6.35%). The loss of an Xho I-site was not found in 9 cases (9/63, 14.29%). Besides loss of an Xho I-site (nt:169423-169428; GAGCTC --> GATCTC), 4 additional missense point mutations were found.
According to the results obtained from this investigation, the PBMCs of 10 EBV carriers residing in Guangdong merely contain EBV variant with wt-Xho I. On the contrary, the EBV variant with XhoI-loss becomes the predominant variant detected in NPC tissues. So, the genomic variation within N-terminus (loss of an Xho I-site and other missense point mutations) of EBV LMP1 gene might be developed in the process of nasopharyngeal carcinogenesis.
众所周知，爱泼斯坦-巴尔病毒（EBV）的潜伏膜蛋白1（LMP1）基因参与鼻咽癌的发生发展。本研究旨在调查从广东鼻咽癌（NPC）中分离出的爱泼斯坦-巴尔病毒（EBV）潜伏膜蛋白1（LMP1）基因N端Xho I位点的缺失情况，以进一步了解LMP1基因参与致癌过程中的序列变异。
收集中山大学肿瘤防治中心63例鼻咽癌患者的新鲜鼻咽活检组织。取10名健康EBV携带者的外周血单个核细胞（PBMC）作为对照。采用QIAamp DNA Mini试剂盒提取活检组织和PBMC的DNA。使用巢式聚合酶链反应（PCR）扩增EBV LMP1基因的N端，然后进行Xho I酶切。采用四色荧光终止子测序法对PCR产物进行双向固相测序。
10名携带者的PBMC中均未检测到EBV LMP1基因N端Xho I位点（野生型Xho I）的缺失。50例（50/63，7９.36%）出现Xho I位点缺失（Xho I缺失），4例（4/63，6.35%）出现部分缺失。9例（9/63，14.29%）未发现Xho I位点缺失。除Xho I位点缺失（核苷酸：169423-169428；GAGCTC --> GATCTC）外，还发现4个错义点突变。
根据本研究结果，广东10名EBV携带者的PBMC仅含有野生型Xho I的EBV变异体。相反，Xho I缺失的EBV变异体是在NPC组织中检测到的主要变异体。因此，EBV LMP1基因N端的基因组变异（Xho I位点缺失和其他错义点突变）可能在鼻咽癌发生过程中出现。
