New Assay Helps Determine Lymphoma Subtypes Simply, Quickly, and Inexpensively
RT-MLPA Assay May Help Clinicians Evaluate Prognosis and Target Effective
Therapies for Lymphoma Patients, According to Report in The Journal of
RT-MLPA Assay May Help Clinicians Evaluate Prognosis and Target Effective Therapies for Lymphoma Patients, According to Report in The Journal of Molecular Diagnostics
With the advent of targeted lymphoma therapies on the horizon, it becomes increasingly important to differentiate the two major subtypes of diffuse large B-cell lymphoma (DLBCL), which is the most common non-Hodgkin lymphoma. These are germinal center B-cell-like (GCB) and activated B-cell-like (ABC), which differ in management and outcomes. A report in The Journal of Molecular Diagnostics describes use of the reverse transcriptase-multiplex ligation-dependent probe amplification (RT-MLPA) assay for differentiating DLBCL subtypes. RT-MLPA is as accurate as the current gold standard technology and offers advantages such as simplicity, flexibility, short turnaround time, low cost, and efficiency.
“Differences in the progression of
the disease and clinical outcomes can, at least in part, be explained by the
heterogeneity of lymphoma, which can be classified into two major subtypes with
different outcomes. Unfortunately, these lymphomas are morphologically
undistinguishable in routine diagnosis, which is a major problem for the
development of targeted therapies. Furthermore, array-based gene expression
profiling (GEP), which is considered the gold standard for discriminating these
tumors, remains poorly transposable to routine diagnosis, and the surrogate
immunohistochemical (IHC) algorithms that have been proposed are often
considered poorly reliable,” explained lead investigator Philippe Ruminy, PhD,
of the Centre Henri Becquerel, Institute for Research and Innovation in
Biomedicine, University of Rouen (France).
Investigators evaluated a simple and rapid RT-MLPA assay. They analyzed lymph node biopsies from 259 patients with de novo DLBCL, including 195 patients from the Centre Henri Becquerel and 64 from an external group (the Lymphoma Study Association).
The RT-MLPA assay was compared to the gold standard method of distinguishing the two lymphoma subtypes. In a training series of 50 randomly selected DLBCL cases, the new method classified 90% of the cases into the expected subtypes (20 GCB and 25 ABC), whereas 10% were considered unclassifiable. In a second independent validation series, 93% of 65 samples were classified correctly with RT-MLPA.
The investigators also showed that
RT-MLPA is sensitive for analyzing archived formalin-fixed, paraffin-embedded
(FFPE) tissue samples. Comparison of samples from paired frozen and FFPE
biopsies showed that the RT-MLPA assay correctly classified 89.3% of 28 cases.
“Because RT-MLPA requires only short cDNA fragments for the correct binding and
ligation of the gene-specific oligonucleotide probes, it is less affected by
the use of low RNA concentrations and RNA degradation. It could thus be used
for the retrospective analysis of archival collections and for the inclusion of
patients in prospective clinical trials, because only a few institutions
routinely collect frozen biopsy material,” noted Dr. Ruminy.
To evaluate the prognostic value of the assay, the researchers looked at survival in 135 treated lymphoma patients diagnosed between 2001 and 2011. They found that patients determined to have the ABC subtype by the RT-MLPA assay had significantly worse progression-free survival and overall survival than those with the GCB subtype. They also found that expression of several individual genes within the MLPA signature was significantly associated with prognosis (ie, high LMO2, high BCL6, and low TNFRSF13B expression).
“The robust and cost-effective RT-MLPA assay can yield results within one day and requires reagents costing less than $5 per sample. Since RT-MLPA utilizes materials and equipment that are standard in many laboratories, the process can easily be implemented for routine use,” stated Dr. Ruminy.
Notes for editors
“Accurate Classification of Germinal Center B-Cell-Like/Activated B-Cell-Like Diffuse Large B-Cell Lymphoma Using a Simple and Rapid Reverse Transcriptase Multiplex Ligation-Dependent Probe Amplification Assay: A CALYM Study,” by Sylvain Mareschal, Philippe Ruminy, Cristina Bagacean, Vinciane Marchand, Marie Cornic, Jean-Philippe Jais, Martin Figeac, Jean-Michel Picquenot, Thierry Molina, Thierry Fest, Gilles Salles, Corinne Haioun, Karen Leroy, Hervé Tilly, and Fabrice Jardin, DOI: http://dx.doi.org/10.1016/j.jmoldx.2015.01.007. Published online ahead of The Journal of Molecular Diagnostics, Volume 17, Issue 3 (May 2015) published by Elsevier.
Full text of this study and commentary is available to credentialed journalists upon request; contact Eileen Leahy at 732-238-3628 or firstname.lastname@example.org. Journalists wishing to interview the author of the study should contact Philippe Ruminy, Centre Henri Becquerel (France) at +33 2 32 08 22 22 or email@example.com.
This research was supported by grants from the French National Cancer Institute (INCA), the ‘Ligue contre le Cancer (comite Seine Maritime),’ the ‘Agir avec Becquerel’ association, the GEFLUC association, and the CALYM consortium.
About The Journal Of Molecular
The Journal of Molecular Diagnostics, (http://jmd.amjpathol.org), the official publication of the Association for Molecular Pathology, co-owned by the American Society for Investigative Pathology, and published by Elsevier, Inc., seeks to publish high quality original papers on scientific advances in the translation and validation of molecular discoveries in medicine into the clinical diagnostic setting, and the description and application of technological advances in the field of molecular diagnostic medicine. The editors welcome for review articles that contain: novel discoveries or clinicopathologic correlations including studies in oncology, infectious diseases, inherited diseases, predisposition to disease, or the description of polymorphisms linked to disease states or normal variations; the application of diagnostic methodologies in clinical trials; or the development of new or improved molecular methods for diagnosis or monitoring of disease or disease predisposition.
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