Molecular biologic and pathologic analysis of Epstein-Barr virus infection related salivary lymphoepithelial carcinoma

我们收集了180例涎腺淋巴上皮癌（LEC），经各种分子生物学方法证实为ebv感染的肿瘤。从患者组织样本中获得了EBV基因之一、被认为是致癌基因的LMP1基因的完整序列。将其克隆到表达载体中，并将构建体转染到293T细胞中。转染不同LMP1基因的载体（如从鼻咽癌中分离的CAO和EBV原型B95-8）转染的细胞也显示出NFkB活性显著升高和细胞生长受到抑制。结果表明，LMP1的表达影响LEC细胞的转录活性，但本研究中发现的整体突变并不总是导致肿瘤发生的原因。对其中20例的LMP1基因启动子区域进行了分析，所有病例在预期与转录因子相关的区域都有共同的突变事件。我们尝试了很多次唾液LECs原代培养。然而，不幸的是，很难从培养的细胞中建立细胞系。在其中一个原代培养中，我们成功地维持了细胞，证实了它们的唾液管上皮和肌上皮特征以及EBV感染。本文通过对64例腮腺淋巴上皮囊肿的临床病理分析，对其作为背景性疾病进行了研究。囊肿的淋巴样间质似乎是局灶性涎腺炎的肉芽组织反应所致，而不是eb病毒感染所致。我们的功能研究为EBV在唾液LEC发病机制中的作用提供了新的视角，尽管仍有必要对EBV致癌的整个机制进行进一步的研究。

We have collected the total 180 cases of lymphoepithelial carcinoma (LEC) of salivary gland, which were confirmed as EBV-infected tumors by various molecular biological.A complete sequence for the LMP1 gene, one of the EBV gene and has been regarded as an oncogene, was obtained from patients' tissue samples. It was cloned into an expression vector and the constructs were transfected into 293T cells. The transfected cells showed significant elevation of NFkB activities and suppressed cell growth, which were also seen in cells transfected with vectors with different LMP1 genes such as CAO, which has been isolated from a nasopharyngeal carcinoma, and B95-8, a prototype EBV. The results indicated that the expression of LMP1 affects transcription activities in LEC cells but that the overall mutations found in the present study were not always reasons for the tumorigenesis. The promoter region of the LMP1 gene was also analyzed from 20 cases of them, and all of the cases shared common mutational events in regions that were expected to be associated with transcription factors.We tried primary cultures for salivary LECs for many times. Unfortunately, however, it was hard to establish cell lines from the cells in culture. In one of the primary cultures, we were successful in maintaining cells, which were confirmed to be their salivary duct epithelial and myoepithelial characteristics as well as EBV infected.As a background disease, lymphoepithelial cyst was studied based on clinicopathological analyses of sixty-four cases of the parotid gland. The lymphoid stroma of the cyst seemed to be resulted from granulation tissue reaction of focal sialadenitis but not induced by EBV infection.Our functional study shows a new insight for EBV roles in the pathogenesis of salivary LEC, although it is still necessary to carry out further investigations for the whole mechanisms of EBV oncogenesis.