Bcl-2 Expression in Normal, Leukemic B-Cells

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Leukemia. 2004 Jan 15 [Epub ahead of print]

Quantitative analysis of bcl-2 expression in normal and leukemic

human B-cell differentiation.

Menendez P, Vargas A, Bueno C, Barrena S, Almeida J, De Santiago M,

A, Roa S, San JF, Orfao A.

[1] 1Servicio General de Citometria, Universidad de Salamanca,

Salamanca, Spain [2] 2Departamento de Medicina and Centro de

Investigacion del Cancer, Universidad de Salamanca, Salamanca, Spain.

Lack of apoptosis has been linked to prolonged survival of malignant

B cells expressing bcl-2. The aim of the present study was to analyze

the amount of bcl-2 protein expressed along normal human B-cell

maturation and to establish the frequency of aberrant bcl-2

expression in B-cell malignancies.

In normal bone marrow (n=11), bcl-2 expression obtained by

quantitative multiparametric flow cytometry was highly variable: very

low in both CD34(+) and CD34(-) B-cell precursors, high in mature B-

lymphocytes and very high in plasma cells. Bcl-2 expression of mature

B-lymphocytes from peripheral blood (n=10), spleen (n=8) and lymph

node (n=5) was significantly higher (P<0.02) in CD23(-) as compared

to CD23(+) B cells, independent of the type of tissue analyzed.

Upon comparison with normal human B-cell maturation, bcl-2 expression

in neoplastic B cells from 144 patients was found to be aberrant in

66% of the cases, usually corresponding to bcl-2 overexpression

(63%). Follicular lymphoma (FL) carrying t(14;18) and MALT lymphoma

were the only diagnostic groups constantly showing overexpression of

bcl-2.

Bcl-2 overexpression was also frequently found in precursor B-acute

lymphoblastic leukemia (84%), typical (77%) and atypical (75%) B-cell

chronic lymphocytic leukemia, prolymphocytic leukemia (two of three

cases), mantle cell lymphoma (55%), but not in t(14;18)(-) FL,

splenic marginal zone lymphoma, Burkitt lymphoma and multiple myeloma.

Leukemia advance online publication, 15 January 2004;

doi:10.1038/sj.leu.2403231

PMID: 14724650 [PubMed - as supplied by publisher]