“Double-Hit” Mature B-Cell Lymphomas Show a Common Immunophenotype by Flow Cytometry That Includes Decreased CD20 Expression

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Blank“Double-Hit” Mature B-Cell Lymphomas Show a Common Immunophenotype by Flow

Cytometry That Includes Decreased CD20 Expression

1.. Wu, MD, PhD1,

2.. Brent L. Wood, MD, PhD1,

3.. Dorer, MD, PhD2 and

4.. R. Fromm, MD, PhD1

+ Author Affiliations

1.. 1From the Departments of Laboratory Medicine, University of Washington

Medical Center; and

2.. 2Pathology, Virginia Mason Medical Center, Seattle

1.. Address reprint requests to Dr Wu: Hematopathology, University of

Washington Medical Center, Seattle Cancer Care Alliance, Campus Box 358081, 825

Eastlake Ave E, Seattle, WA 98109.

Abstract

Lymphomas with 2 translocations involving c-MYC and BCL2 or BCL6 are a subset of

biologically aggressive mature B-cell lymphomas now frequently categorized under

the entity of B-cell lymphoma, unclassifiable, with features intermediate

between Burkitt lymphoma and diffuse large B-cell lymphoma. We identified a

cohort of these lymphomas in our databases and retrospectively reviewed

corresponding in-house flow cytometric data to determine whether a common

immunophenotype might be present. Herein we report on our findings on 10

lymphomas, each with translocations involving c-MYC and BCL2 or BCL6 and show

that these cases frequently showed a common immunophenotype that includes

decreased expression of CD20. Because these lymphomas often show aggressive

biologic behavior and poor clinical outcome, recognition of this relatively

common immunophenotype may be useful for identifying cases for confirmatory

cytogenetic studies, as often, flow cytometry provides the first assessment of

these clinical specimens.