S. Eissa et al., Correlation between EBV DNA and rearrangement and expression of bcl-2 genein aggressive non-Hodgkin's lymphoma, IUBMB LIFE, 48(2), 1999, pp. 231-236
Previous in vitro studies have shown that bcl-2 expression can be induced b
y transfection of Epstein-Barr virus (EBV)-negative non-Hodgkin's lymphoma
(NHL) cell lines with EBV, This induced expression of bcl-2 is important fo
r the long survival of EBV-positive cells and might be a first step in tumo
rigenesis, The purpose of the present study was to investigate the possibil
ity of similar correlation between bcl-2 expression and EBV infection in vi
vo in a cohort of patients with aggressive NHL, who were uniformly evaluate
d and treated with effective chemotherapy, The 42 patients included were 25
-65 years old, None had prior treatment, discordant lymphoma, or human immu
nodeficiency virus seropositivity, Fresh biopsied samples were obtained and
stored frozen for analysis of bcl-2 gene rearrangement major break point a
nd of EBV DNA by PCR, Bcl-2 protein expression was estimated by Western blo
t, and enzyme immunoassay, With a median follow-up of 30 months, overall su
rvival (OS) and disease-free survival (DFS) were measured to determine the
prognostic significance of these variables. Analyzable DNA was present in a
ll samples, 24% demonstrating bcl-2 rearrangement and 33% showing EBV DNA,
Patients with bcl-2 gene rearrangement tended to have shorter DFS, and OS t
han patients without translocation, Bcl-2 protein expression was not correl
ated to gene rearrangement and had no significant influence on survival. Th
e presence of EBV DNA in NHL had no prognostic significance but was correla
ted to bcl-2 expression. EBV-positive tumors showed higher bcl-2 expression
than EBV-negative tumors did. Our results suggest a role of EBV infection
in inducing bcl-2 expression as a survival factor for EBV-positive cells.