Bf. Skinnider et al., Bcl-6 and bcl-2 protein expression in diffuse large B-cell lymphoma and follicular lymphoma: Correlation with 3q27 and 18q21 chromosomal abnormalities, HUMAN PATH, 30(7), 1999, pp. 803-808
Citations number
37
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
The bcl-2 gene on chromosome 18 at q21 and the bcl-6 gene on chromosome 3 a
t q27 are both highly regulated during B-cell differentiation and show an i
nverse relationship of expression in the normal secondary lymphoid follicle
. The objective of this study was to investigate the relationship between b
cl-2 and bcl-6 protein expression and the relationship between protein expr
ession and the corresponding chromosomal alterations in malignant lymphomas
, including those associated with the germinal center. Expression of bcl-2
and bcl-6 proteins was studied in 55 cases of diffuse large B-cell lymphoma
(DLBCL) and 21 cases of follicular lymphoma (FL), and the results correlat
ed with the presence of t(14;18) and 3q27 abnormalities in a subset of 52 c
ases with cytogenetic analysis. These cases were selected to represent a sp
ectrum of nodal and extranodal lymphomas, including those with and without
a t(14;18), It was shown that the neoplastic cells in 71% of DLBCLs and 100
% of FLs expressed bcl-6 protein. Expression of bcl-6 was seen more frequen
tly in diffuse large B-cell lymphomas with large noncleaved morphology comp
ared with immunoblastic morphology (82% v 27%, P = .0015), but failed to co
rrelate with 3q27 abnormalities, Thirty-eight percent of cases with 3q27 ab
normalities were bcl-6 protein negative, whereas 85% of cases without a 3q2
7 abnormalities were bcl-6 protein positive. Expression of bcl-2 protein wa
s shown in 51% DLBCLs (nodal v extranodal, 71% v 30%, P = .012). bcl-2 prot
ein was expressed in 89% of FLs with t(14;18), in contrast to 25% of FLs, w
ithout t(14;18) (P = .016). In DLBCL and FL with t(14;18), the most common
pattern of expression was bcl-2(+)/bcl-6(+). In lymphomas without t(14;18),
there was not an inverse relationship between bcl-2 and bcl-6 protein expr
ession. In conclusion, these data suggest that mechanisms other than gene r
earrangements can deregulate bcl-2 and bcl-6 expression in lymphomas, and t
here does not appear to be an inverse relationship between these two protei
ns as seen in the normal germinal center. Copyright (C) 1999 by W.B. Saunde
rs Company.