Genomic profiling using array comparative genomic hybridization define distinct subtypes of diffuse large b-cell lymphoma: a review of the literature

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-HodgkinLymphoma comprising of greater than 30 % of adult non-Hodgkin Lymphomas. DLBCLrepresents a diverse set of lymphomas, defined as diffuse proliferation of large B lymphoidcells. Numerous cytogenetic studies including karyotypes and fluorescent in situhybridization (FISH), as well as morphological, biological, clinical, microarray andsequencing technologies have attempted to categorize DLBCL into morphological variants,molecular and immunophenotypic subgroups, as well as distinct disease entities. Despite suchefforts, most lymphoma remains undistinguishable and falls into DLBCL, not otherwisespecified (DLBCL-NOS). The advent of microarray-based studies (chromosome, RNA, geneexpression, etc) has provided a plethora of high-resolution data that could potentiallyfacilitate the finer classification of DLBCL. This review covers the microarray data currentlypublished for DLBCL. We will focus on these types of data; 1) array based CGH; 2) classicalCGH; and 3) gene expression profiling studies. The aims of this review were three-fold: (1)to catalog chromosome loci that are present in at least 20 % or more of distinct DLBCLsubtypes; a detailed list of gains and losses for different subtypes was generated in a tableform to illustrate specific chromosome loci affected in selected subtypes; (2) to determinecommon and distinct copy number alterations among the different subtypes and based on thisinformation, characteristic and similar chromosome loci for the different subtypes weredepicted in two separate chromosome ideograms; and, (3) to list re-classified subtypes andthose that remained indistinguishable after review of the microarray data. To the best of ourknowledge, this is the first effort to compile and review available literatures on microarrayanalysis data and their practical utility in classifying DLBCL subtypes.Although conventional cytogenetic methods such as Karyotypes and FISH have played amajor role in classification schemes of lymphomas, better classification models are clearlyneeded to further understanding the biology, disease outcome and therapeutic management ofDLBCL. In summary, microarray data reviewed here can provide better subtype specificclassifications models for DLBCL.

via Journal of Hematology & Oncology