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To characterize the sequence variation and the potential implication of the Epstein-Barr virus (EBV) oncogene in lymphoma, BamHI-C fragment rightward reading frame 1 (BCRF1) was sequenced in different types of EBV-positive lymphoma in northern China, and polymorphisms were compared with previous variation data from other malignancies. The dominate subtype of BCRF1 in EBV-positive lymphoma was the B95-8 prototype, and a mutation in the signal peptide was more strongly associated with Hodgkin's lymphoma. The high conservation of BCRF1 in EBV-positive lymphoma suggests its important role in maintaining the basic biological activity and immunosuppressive functions of the virus. [ABSTRACT FROM AUTHOR]

Epstein-Barr virus (EBV) is responsible for the development of multiple tumors, including EBV-associated gastric carcinoma (EBVaGC), but little is known about its mechanisms in EBVaGC. WNT5A expression and promoter methylation were measured in 5 EBV-positive and 15 EBV-negative GC cell lines. The methylation status of 23 EBV-positive and 25 EBV-negative paired tumor/normal tissue samples was also examined. EBV-positive GC had no or very low expression of WNT5A but a high level of methylation in the promoter region. In contrast, EBV-negative GC had higher WNT5A expression and a lower level of promoter methylation. The reduced WNT5A expression could be restored by treatment with Aza, a methyltransferase inhibitor. Increased expression of WNT5A in vitro inhibited β-catentin expression in EBVaGC cells (SNU719). These results suggest that hypermethylation of WNT5A induced by EBV may contribute to the development of EBVaGC. Ectopic introduction of WNT5A may have preventive/therapeutic potential for tumors with silenced WNT5A. [ABSTRACT FROM AUTHOR]

To characterize the sequence variation of the gp350/220 and explore its potential association with EBV-associated tumors, the gp350/220 gene was sequenced from 41 EBV-associated gastric carcinoma (EBVaGC) and 81 nasopharyngeal carcinoma (NPC) biopsies as well as 35 throat washing (TW) samples from healthy donors. Preferential linkages between variants of the N-terminus of gp350/220 and EBNA3C variants were detected, and type A/BLLF1-a was the dominant variant in this study. The dominant variant in the C-terminal region of gp350/220 was 9P. The similar distribution of gp350/220 variants in NPC, EBVaGC and healthy donors suggest that gp350/220 variations are geographically restricted rather than tumor-specific polymorphisms. [ABSTRACT FROM AUTHOR]