Genome-wide microarray-based comparative genomic hybridization analysis of lymphoplasmacytic lymphomas reveals heterogeneous aberrations

Abstract

Lymphoplasmacytic lymphoma (LPL) is not a sharply delineated lymphoma entity, either morphologically, phenotypically, or clinically. The diagnosis is often made by excluding other small cell lymphomas with plasmacytic differentiation, thus a genetic diagnostic marker would be of great benefit. Conventional cytogenetic techniques have previously demonstrated a deletion of 6q in a proportion of cases, varying from 7 to 55%. In this report, we apply array-based comparative genomic hybridization on 11 LPL samples. Genomic aberrations were detected in 9 of 11 cases, and included gains and losses. In general, the number of genetic aberrations was relatively low (two to three abnormalities per case). Recurrent aberrations detected were deletion of 6q (two cases), deletion of chromosome 17 (two cases), gain of 3q (two cases), and gain of chromosome 7 (two cases). This report not only confirms the reported loss of 6q in a proportion of cases but also highlights the genetic heterogeneity of LPL, in accordance with the known immunophenotypical, morphological, and clinical diversity of the disease.

Keywords:

• Lymphoplasmacytic lymphoma
• Waldenström macroglobulinemia
• LPL/WM
• array-CGH
• DNA copy number
• deletion
• gain