Researchers at Radboudumc have developed a new technique that allows pathologists to better detect the presence of a lymphoid malignancy. The method is based on sequencing of DNA from a biopsy of enlarged lymph nodes with next-generation sequencing. This approach allows a better distinction between inflammation and lymphoma, based on the clonality of certain receptor molecules on white blood cells.
Lymphoma is a collective term for various diseases caused by a malignant proliferation of white blood cells in the lymph nodes. In the Netherlands, approximately 3,600 people are diagnosed with lymphoma annually. Fifteen percent of the cases are Hodgkin's lymphoma; the rest consist of various forms of non-Hodgkin's lymphoma. An important symptom is enlarged lymph nodes, but this may also arise due to inflammation.
It is therefore important for the diagnosis that a pathologist can distinguish between inflammation and cancer in a lymph node biopsy. "In fact, we've been able to perform this assay in the past twenty years," explain researchers Blanca Scheijen and Clinical Scientist in Molecular Pathology Patricia Groenen. "But the method we use for this assessment has undergone tremendous developments. We have now set up a new assay using next-generation sequencing, which provides more detailed information than the current standard method."
The analysis is based on the unique DNA code of antigen receptors on white blood cells. Each white blood cell has a different receptor with its own unique DNA code. In case of a lymphoma, a single white blood cell grows into a tumor. Therefore, the cells in a lymphoma all possess the same receptor molecule and therefore an identical DNA code; they form, in fact, a clone. In inflammation, on the other hand, the variation in these receptor molecules is much larger. Thus, DNA analysis determines whether a biopsy contains an inflammation or a lymphoma based on the diversity of the receptor molecules.
In the current conventional method used worldwide, laboratory specialists look for this variation based on the lengths of DNA fragments, which contain the information for receptor molecules. The new assay with next-generation sequencing analyzes the genetic material much more in-depth. Blanca Scheijen explains the advantages: "We show that this new technique is both more specific and more sensitive than the current method. Especially in Hodgkin lymphoma, we see a three to four times improved identification of unique DNA codes. This allows us to detect tumor cells in more cases. In addition, less biopsy material is needed."
The new method, which was developed within the European network EuroClonality, will probably become available for standard diagnostics at the Radboudumc in the course of the coming year. In addition, the European network is working with a company on a ready-to-use kit for this diagnostic test, so that the method can easily be implemented in other hospitals.
The new technique offers another advantage. Scheijen: "If a lymphoma patient returns to the hospital with complaints that may imply disease recurrence, we can also more clearly distinguish whether the initial lymphoma has returned or whether a new tumor has developed. This makes a big difference because a new lymphoma generally requires less intensive treatment. Thus, this has a huge impact on the treatment strategy and side effects for a patient."
More global genomic analysis may help in the future to determine why some patients respond well to a particular treatment and others do not. Scheijen: "There are many different types of lymphoma, which are often quite heterogeneous, making it difficult to apply predictive diagnostics. When you look into specific characteristics of the tumor, you may be able to offer a personalized therapeutic strategy. This broader genomic analysis is also under development for lymphoma."
Lymphoma is seen on the left, inflammation on the right. DNA analysis of both tissue types shows much more variation in receptor molecules on the white blood cells in inflammation as compared to lymphoma.
About the publications
This work has been described in three publications:
Leukemia 2019: Next-generation sequencing of immunoglobulin gene rearrangements for clonality assessment: a technical feasibility study by EuroClonality-NGS. Blanca Scheijen, Ruud W. J. Meijers, Jos Rijntjes, Michèle Y. van der Klift, Markus Möbs, Julia Steinhilber, Tomas Reigl, Michiel van den Brand, Michaela Kotrová, Julia-Marie Ritter, Mark A. Catherwood, Kostas Stamatopoulos, Monika Brüggemann, Frédéric Davi, Nikos Darzentas, Christiane Pott, Falko Fend, Michael Hummel, Anton W. Langerak, Patricia J. T. A. Groenen.
The Journal of Molecular Diagnostics 2021: Next-Generation SequencingeBased Clonality Assessment of Ig Gene Rearrangements. A Multicenter Validation Study by EuroClonality-NGS. Michiel van den Brand, Jos Rijntjes, Markus Möbs, Julia Steinhilber, Michèle Y. van der Klift, Kim C. Heezen, Leonie I. Kroeze, Tomas Reigl, Jakub Porc, Nikos Darzentas, Jeroen A.C.W. Luijks, Blanca Scheijen, Frédéric Davi, Hesham ElDaly, Hongxiang Liu, Ioannis Anagnostopoulos, Michael Hummel, Falko Fend, Anton W. Langerak, and Patricia J.T.A. Groenen.
Modern Pathology 2021: Clonality assessment and detection of clonal diversity in classic Hodgkin lymphoma by next-generation sequencing of immunoglobulin gene rearrangements. Diede A. G. van Bladel, Michiel van den Brand, Jos Rijntjes, Samhita Pamidimarri Naga, Demi L. C. M. Haacke, Jeroen A. C. W. Luijks, Konnie M. Hebeda, J. Han J. M. van Krieken, Patricia J. T. A. Groenen and Blanca Scheijen.
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