| Epstein-Barr virus (EBV) is a human herpesvirus that establishes a life-long persistence in the host. The virus infects the vast majority of the world's adult population and is well known for its association with a broad spectrum of benign and malignant diseases, including infectious mononucleosis, Burkitt's lymphoma, nasopharyngeal carcinoma, B-cell lymphoma in immunocompromised patients, and gastric carcinoma. In vitro EBV infection of peripheral B lymphocytes results in their immortalization and continuous proliferation. EBV has two kinds of infection, latency and lytic. In immortalized lymphoblastoid cell lines, a kind of latency EBV infection, EBV expresses six nuclear proteins (EBNAs), three integral membrane proteins (LMP1, -2A, and -2B), two small nuclear RNAs (EBER1and -2), and a transcript from the relBamHI-A region. EBV has a recognized association with epithelial cancers. Nasopharyngeal carcinoma is the most familiar meligent cancer to EBV, about 90%～100% nasopharyngeal carcinoma with EBV positive. Latent membrane protein 1 (LMP1) is one of the viral gene products that are essential for EBV-induced B-cell transformation, is also abundantly expressed during the lytic cycle of viral replication. However, the biological significance of this strong LMP1 induction remains unknown. LMP1 is an integral membrane protein composed of a short cytoplasmic amino-terminal domain, six hydrophobic transmembrane domains, and a cytoplasmic carboxy-terminal domain. It has been demonstrated that LMP1 acts as a constitutively active receptor that mimics activated CD40, a member of the tumor necrosis factor receptor family. Through its binding to a tumor necrosis factor receptor-associated factor (TRAF) and a tumor necrosis factor receptor-associated death d (TRADD) protein, the cytoplasmic carboxy terminus of LMP1 plays a critical role in EBV-induced B-cell transformation. LMP1 is the only oncogene derives from...
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