Abstract
To assess the role of the Epstein‐Barr virus (EBV) latent membrane protein 1 (LMP1) gene in the development of Hodgkin's lymphoma (HL), the polymorphism of this gene in EBV isolates from different geographic locations was analyzed. A 497 bp fragment spanning LMP1 gene exons 1 and 2 was amplified by polymerase chain reaction (PCR), using a primer pair bracketing a Xhol restriction site. PCR products were subjected to Xhol digestion and to DNA sequencing analysis. Twenty‐five HL biopsy specimens from the United States and five HL and four non‐Hodgkin's lymphoma (NHL) biopsy specimens from Italy were examined. Eighty percent of LMP1‐positive samples (12 of 15) from the United States maintained the Xhol restriction site and the remaining 20% partially lost the Xhol site. One of four EBV‐positive HL and one of the three EBV‐positive NHL specimens from Italy lost the restriction site. The other three EBV‐positive HL DNAs were partially cut by Xhol. Direct DNA sequencing analysis revealed that those Italian samples not digested by Xhol were due to a G to C transversion at the first base of codon 18, resulting in the change of glycine to arginine. Those DNA samples partially cut by Xhol were due to a mixture of G/C at the same location. In contrast, those partially digested American HL DNAs had a mixture of G/T at the second base of codon 17. The sequence variation found in the Italian samples differs from that of Asian EBV strains, in which G to T transversion was detected at codon 17, resulting in the substitution of arginine by leucine. Among the 72% (18 of 25) EBV‐positive American HL samples, 67% (12 of 18) were associated with type A virus, 17% (3 of 18) with type B, and 17% (3 of 18) with dual viral sequences. EBV DNA was detected in 80% (four of five) of Italian HL biopsy specimens, in which 50% (two of four) were associated with type A and 50% (two of four) with type B. Despite these sequence variations at the Xhol recognition site between EBV isolates of different geographic locations, no direct correlation with a specific genotype was observed. These results, to our knowledge, represent the first observation of a specific point mutation at codon 18 of LMP1 gene associated with a particular geographic location. It appears that the Xhol polymorphism may be a useful molecular marker for epidemio‐logic study, and the alteration in the LMP1 gene may have functional significance in the development of HL in certain geographic areas. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.