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Deletion of Epstein-Barr Virus Latent Membrane Protein 1 Gene in Japanese and Brazilian Gastric Carcinomas, Metastatic Lesions and Reactive Lymphocytes
Kazuhiko Hayashi,¹ Tadaatsu Akagi,¹ Ichiro Murakami,² Nobuya Ohara,¹ Hong-Li Chen,¹ Soichiro Nose,³ Kazuo Hamaya,³ Karen L. Chang,⁴ and Lawrence M. Weiss⁴ (¹Departments of Pathology, Okayama University Medical School, Okayama, Japan; ⁴City of Hope National Medical Center, Duarte, CA; ²Iwakuni National Hospital, Iwakuni; ³Okayama Saiseikai General Hospital, Okayama, Japan)

Information on a 30-basepair (bp) deletion of LMP1 gene in EBV-associated gastric carcinoma (EBVaGC) is limited. We studied the prevalence of 30-bp LMP1 gene deletion in EBVaGC in Japan (29 cases) and Brazil (4 cases) in comparison to their EBER1-positive metastatic carcinoma in lymph nodes (10 cases) and EBV-infected reactive lymphocytes. We studied the status of the LMP1 gene by Southern blot hybridization of PCR products obtained after amplification with primers flanking the site of the deletion. EBV DNA was amplified by PCR in 30 of 33 EBVaGC cases, 8 of 10 metastatic carcinomas, 14 non-neoplastic tissues from 27 EBVaGC cases and 12 of 25 non-EBV-associated GC cases with EBER1-positive lymphocytes. The 30-bp LMP1 gene deletion was observed in 23/26 (88.5%) cases of EBVaGC from Japan, and 2/4 (50%) cases of Brazilian EBVaGC, as compared to EBER1-positive reactive lymphocytes from 11/14 (78.6%) EBVaGC cases and from 9/12 (75%) cases of non-EBV-associated GC. The variant type of LMP1 gene was the same among reactive lymphocytes, primary and secondary lesions of EBVaGC in all cases (6/6). Presence of this 30-bp deletion has no correlation with histological stage of cancer invasion or presence of metastasis. The similar high incidence of 30-bp deletion in LMP1 gene in both carcinoma cells and reactive lymphocytes in EBVaGC cases suggests that this deletion may not be relevant to the pathogenesis of EBVaGC.