Epstein-Barr virus-Associated Lymphomas in Malaysia: High Frequency of a 30-bp Deletion in the Viral Latent Membrane Protein-1 (LMP-1) Oncogene

A variant of Epstein-Barr virus (EBV) with a 30-base pair (bp) deletion in the latent membrane protein-1 (LMP-1) gene has been reported in many EBV-associated malignancies at different frequencies in different geographical locations. This study aims to determine the frequency of this variant in Asian EBV-associated lymphomas. We analyzed a total of 81 cases of known EBV-associated lymphomas [20 classical Hodgkin's, 19 Burkitt's, 33 T-and natural killer (NK)/T-cell, and 9 diffuse large B-cell lymphomas (DLBCL)] and 19 reactive lymphoid tissues from the archives. The presence of the 30-bp deletion at the 3' end of the LMP-1 gene was demonstrated by hybridization of polymerase chain reaction (PCR) products after amplification with a pair of primers flanking the deletion region. The DNA from 96.3% (78/81) of the lymphomas and 78.9% (15/19) of the reactive lymphoid tissues were amplified by PCR. The lymphomas showed infection by the deleted variant in 91.0% (71/78) of the cases, including 33.3% (26/78) cases with dual variant infection. The deleted variant was observed in 100% (19/19) of the Burkitt's lymphoma, 89.5% (17/19) of the classical Hodgkin's lymphomas, 90.6% (29/32) of the T-and NK/T-cell lymphomas and 75.0% (6/8) of DLBCL, whereas it was detected in 60.0% (9/15) of the reactive lymphoid tissues. The difference in the frequency of deleted LMP-1 variants observed between the lymphomas and the reactive lymphoid tissues was statistically significant (p=0.006). A significant difference was also observed between childhood and male lymphoma patients and reactive lymphoid controls of comparable age or gender group (p