Published: October 10, 2007
The clinicians and researchers of the Centre for Lymphoid Cancer are involved in numerous projects to increase our understanding of lymphoid cancers such that better diagnostic and therapeutic approaches can be made available to diagnose and treat these diseases.
Descriptions of some of our projects are listed here:
The CLC's research projects are made possible by the support of following groups:
Lymphoid Cancer Database
Dr Joseph Connors and his co-investigators, Dr Randy Gascoyne and Dr Doug Horsman, have assembled a clinical-pathological-cytogenetic database with computerized treatment and follow-up records of more than 13,000 patients with electronic cross-linkage to pathology and genetic data making it one of the largest and most complete such databases in the world. This resource has enabled the development of novel lymphoma treatments that have been tested and emulated worldwide and the study of late complications of successful lymphoma treatment. The database is uniquely comprehensive and contains detailed follow-up available in only a few other centers in the world.
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High resolution analysis of follicular lymphoma genomes
Follicular lymphoma, the most common type of lymphoma seen in Canada, is a cancer of lymphocytes, the cells of the immune system. Follicular lymphoma is associated with a specific genome rearrangement in which parts of chromosomes 14 and 18 are swapped. This alteration results in the increased production of a protein called BCL2, which blocks lymphocytes from dying normally at the end of their usual life span, so that a group of damaged cells accumulates in the body. These abnormally persistent cells then accumulate other genetic changes, eventually leading to the cancer we call lymphoma. These other genetic changes are likely to be genomic rearrangements. Further, genomic rearrangements may underlie the progression from follicular lymphoma to a very aggressive form of the disease, diffuse large B cell lymphoma.
It has been recognized for many years that genomic rearrangements can contribute to or even cause disease. However, assembling a complete catalogue of all disease-associated chromosomal rearrangements has thus far proven very difficult. This is because the technologies historically available for detecting such rearrangements are very time consuming and, until now, have produced only crude data. With the availability of new, high-resolution tools it is now appropriate to discover the spectrum of cancer-associated rearrangements and to study the effects that such rearrangements have on human genes and cancer cells.
We aim to discover the genomic rearrangements contributing to development of follicular lymphoma and the additional rearrangements contributing to the progression from follicular lymphoma to diffuse large B cell lymphoma. This will be done using several new cutting-edge experimental techniques that were developed by us and others in response to the challenges of the human genome project. We will use such technologies to undertake a high resolution analysis of 24 lymphoma genomes. The scope and scale of our project is unprecedented, representing the first time any group has applied all these technologies directly to profiling the genomes from a human cancer. Because this will be the first such analysis of lymphoma, we expect to find previously undiscovered, recurrent genomic rearrangements specific for lymphoma but likely also relevant to cancer in general. Next, we will study the detailed properties of the rearrangements by determining the actual chemical structure of the rearranged DNA. This will allow us to understand with great precision the genetic consequences of the rearrangements and the genes involved. Knowledge of the precise abnormalities of the key genes that are functioning abnormally in lymphomas will permit us and other researchers in the future to define and explore their biological functions and to evaluate them as new diagnostic and prognostic markers and potential targets for new therapies.
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Genetics based research on lymphomas in British Columbia
Gene expression studies
The pattern of gene expression determines cell behavior including malignant behavior. Thus, determining the pattern of gene expression becomes a way of fundamentally understanding how malignant lymphoid cancer cells behave and what changes need to be reversed to cure the condition. One approach to genetics based research on lymphoma called gene expression profiling proceeds in several steps. Genes are the units of DNA that encode the information necessary to make proteins, the fundamental building blocks of cells and tissues. Genes are transcribed into messenger RNA molecules, which are then translated into proteins. Isolating RNA from cancer cells allows a thorough look at the "transcriptome", otherwise known as expression profile of the cells. Microarray technology now allows us to look at as many as 42,000 genes in one experiment. Many such experiments are being done in Dr. Gascoyne's laboratory.
A complementary technique uses microarray techniques to examine alterations in the copy number of genes at the level of the DNA. First, cells from a patient's lymphoma are analyzed to identify any places where the chromosomes, the units of the genetic system, are abnormally broken. This analysis identifies regions of frequent chromosomal abnormality to be further analyzed. Second, the Lymphoma Genomics Core laboratory run by Dr. Wan Lam uses its resources to build detailed physical maps of the chromosomal regions involved in lymphoma development. This pinpoints the location of the genes for further study. Third, artificial copies of the lymphoma-associated genes are constructed with synthetic DNA. Fourth, tiny quantities of these copies are fixed to special slides called micro-arrays that are used to determine if that specific gene is present in new samples. Finally, presence or absence of the specific genes is quantified to decide if that gene is playing a role in a particular type of lymphoma. The information from these gene studies is used to identify specific genes whose activity is linked to the malignant behavior of the lymphoma. That, in turn, provides a target for future treatments.
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Gene discovery
Determination of the genetic and environmental factors that affect susceptibility to the lymphoid cancers is of increasing importance in efforts to prevent or control them.
The laboratory team supervised by Dr Angela Brooks-Wilson identifies inherited genetic factors that increase the risk of developing a lymphoid cancer. Their studies address whether specific inherited differences in key genes involved in lymphoid cell survival affect susceptibility to lymphoid cancers. Lymphoid cell survival genes include those that control apoptosis, or programmed cell death, and others that govern gene repair mechanisms. Subtle variations in these genes may affect the number of lymphoid cells available to undergo mutation or unable to reverse mutations once they have occurred, contributing to lymphoid cancer susceptibility.
One of this team's studies is based partly on the analysis of an existing large case / control collection of DNA samples from 800 lymphoma patients and 800 unaffected controls and has already led to the discovery of new potential lymphoid cancer susceptibility genes. In another proposed project this team intends to study families that have more than one member with a lymphoid cancer. The unique and powerful CLC Lymphoid Cancer Database established by the BC Lymphoma Tumor Group over the last 23 years will be used to ascertain interested lymphoid cancer families. Funding is being sought to allow us to: 1) support a part-time staff member to use the Lymphoid Cancer Database to recruit and obtain informed consent from members of lymphoid cancer families, 2) support other costs of sample collection including blood-drawing and sample shipping and 3) pay for laboratory costs such as consumable lab reagents, custom genotyping assays and sequencing reactions. This research on the identification of genetic factors that predispose to lymphoid cancers may be useful in the development of panels of diagnostic tests to help identify individuals at risk for these cancers. Combined with effective monitoring techniques, such tests may assist in the early diagnosis of this cancer in at-risk individuals, allowing treatment at a time when the cancer is less developed and more amenable to treatment.
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Biology of Cancer: Follicular lymphoma as a model of cancer progression
In order to improve on the currently incomplete understanding of the multi-step process of cancer initiation, growth, invasion and metastasis we intend to focus on follicular lymphoma, bringing to bear our extensive experience gathered over 20 years, employing the most advanced new molecular genetic analytic techniques.
Follicular lymphoma is one of the two most common lymphomas seen in Canada (>25% of new lymphoma cases are follicular; annual incidence >1500; prevalence >20,000) and is linked to a specific genetic abnormality in which a part of chromosome 18 moves to chromosome 14 where it is abnormally overexpressed resulting in overproduction of a protein called BCL2, which causes cells not to die despite aging and accumulated genetic errors. Most follicular lymphomas spend years as indolent but widespread disease but eventually give rise to a more rapidly progressive invasive and lethal cancer, diffuse large B-cell lymphoma (10 y survival < 20%). This transformation offers a unique opportunity to study, at the molecular level, how a slow-growing cancer progresses into a lethal disease.
Over the past 20 years our research team has developed a comprehensive approach systematically assembling linked computerized databases with full clinical and laboratory data on more than 10,000 lymphoma cases. We have been joined by a team of internationally recognized leaders in the exploration of how the human genome, the full set of the genes which determine how our body's cells actually work, can be examined to improve understanding of cancer. We intend to use this extensive past experience and these new genomic techniques to examine the biology of follicular lymphoma in more complete detail than has been previously possible. Improved fundamental understanding of the genetics predisposing to development of lymphoma should lead, for the first time, to potential methods of early detection or even prevention. Isolation of the crucial genetically driven steps in lymphoma progression will immediately suggest novel targets for new treatments.
Our research plan is composed of four interactive modules encouraging cross-communication so that each module enhances and guides the other three. The first module will focus on a very recently created model mouse which is genetically programmed for overexpression of BCL2. We will be able to isolate and characterize the multiple effects of this abnormality. The second module will examine genetic factors influencing susceptibility to follicular lymphoma using blood specimens from 180 patients and 750 normal controls to examine the contribution of genetic variation to lymphoma development. Individual genes will be examined for variants associated with increased risk of developing lymphoma. This project has the potential to uncover previously unsuspected genes that cause lymphoma. The third module will focus on the chromosomal abnormalities that accumulate as lymphoma develops and progresses. We will focus on chromosome 12 (abnormal in 20% of follicular lymphomas); the X-chromosome (the female sex chromosome) (men develop lymphoma more frequently than women); and paired specimens before and after the follicular lymphoma changes from a slow growing cancer to a fast growing lethal type. The fourth module will directly examine how the cancer cells of follicular lymphoma differ from normal cells at the most basic level, that of the genes themselves. Using a very powerful new technique that allows examination of the entire genetic code of the malignant cells, the whole genome (the entire set of genes that determine how our cells behave) of follicular lymphoma cells will be examined in minute detail allowing us to find many previously unidentified genetic abnormalities present at diagnosis and the new abnormalities that develop as this cancer progresses.
Understanding cancer progression will only yield to comprehensive approaches aimed at well-understood model systems such as that of follicular lymphoma. Our research team, combining extensive experience and sophisticated new genetically based techniques, is uniquely positioned to examine entirely new aspects of cancer progression with major therapeutic implications for both follicular lymphoma but cancer in general.
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Myeloma Research at the BC Cancer Agency
Myeloma is one of a set of diseases that start in B lymphocytes, the cells that make up part of our immune system and are responsible for making antibodies. We have a large number of projects investigating the cancers that develop from B lymphocytes, including myeloma, lymphoma, leukemia and Hodgkin lymphoma. All of these projects produce new insights relevant to that whole family of lymphoid cancers. The following is a short list of some of the research being done into B cell cancers including myeloma at the BC Cancer Agency.
- Treatment of myeloma with bortezomib and lenalidomide. Bortezomib and lenalidomide are promising new chemotherapy drugs that work by novel mechanisms involving the structures in cells that allows them to remove waste or unneeded proteins called the proteosome (bortezomib) and the process by which cancers attract new blood vessels. The BC Cancer Agency is participating in clinical trials testing the effectiveness of bortezomib and lenalidomide in myeloma.
Stem cell transplant for myeloma. The BC Cancer Agency has one of the larger stem cell transplant programs for myeloma in North America and has conducted research into how best to use this treatment technique for myeloma for more than 6 years.
- The myeloma specialists at the BC Cancer Agency participate in clinical research trials being performed by the National Cancer Institute of Canada Clinical Trials Group allowing us to have access to the newest treatments being tested for myeloma and to contribute to the studies that will identify the best treatments in the future.
- A special research fund has been set up by a patient's family, the Toye Fund, to conduct research into myeloma and other B cell cancers. This fund is used to support research in several areas including finding the causes of B cell cancers, identifying the genes that are functioning incorrectly in B cell cancers and searching for the key gene expression pathways that, when found, reveal the best points of attack for new treatments.
Additional projects focused on B cell cancers are investigating what genetic constitution permits myeloma and lymphoma to develop, what environmental and occupational factors encourage myeloma and lymphoma to develop, which genes are abnormally active in myeloma and lymphoma, what new drugs can we test to attack these crucial abnormal genes and how can we best help patients to cope with the leftover toxicity of chemotherapy and radiation years after they have been cured or had their B cell cancer brought under control.
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Mantle Cell Lymphoma Research Project
Improvements in the treatment and eventual cure of mantle cell lymphoma (MCL) will require new insights into the biology of the disease and design and testing of new agents guided by these new discoveries. We intend to identify new aspects of MCL biology, to understand the pathogenesis of the disease, to identify new targets critical to disease progression and to develop novel therapeutic agents which target the most promising of these newly discovered molecular alterations, to verify the efficacy of these new agents and initiate clinical trials to establish their effectiveness. The following projects are planned: (1) creation of a large tissue microarray resource that allows rapid validation of protein expression of hundreds of clinically-linked cases; (2) candidate gene-based testing of why men are so much more likely to develop MCL; (3) examination of the complete genome of each patient to identify all genes with abnormal copy number changes affecting gene expression; (4) analysis of changes in the genetic control and function of the centrosome, the structure that controls chromosomal distribution to daughter cells, in MCL cells; (5) identification of the genetic changes within MCL cells using enhanced cytogenetic techniques; (6) identification of novel membrane-bound proteins that are over-expressed on the surface or within cell membrane fraction of MCL cells, which will serve as new targets for antibody-based therapy; (7) use of cell lines and animal tumor models to determine the optimal dose, timing and combinations of new targeted treatments, and (8) molecular analyses of the gene expression changes in MCL cells in response to targeted treatments of newly identified proteins in animal models, in order to gain insights into the interaction between different pathways relevant to the biology of MCL.
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Molecular signatures to improve diagnosis and outcome prediction in non-Hodgkin lymphoma (NHL)
Gene expression signatures that define the common categories of non-Hodgkin's lymphoma (NHL) have been identified, including some unique subtypes not recognized previously. Molecular prognosticators for these NHLs have also been described. Working in collaboration with an international team of scientists we have recently participated in the development of a DNA microarray with over 2500 features, including all known diagnostic and prognostic parameters for lymphoid cancers. In this collaboration we propose to use this array to study 2400 new cases to validate and refine current as well as newly discovered gene expression signatures and algorithms as the study progresses. Completion of this aim will provide a robust, cost-effective system for accurate diagnostic and prognostic applications. An alternative, quantitative messenger RNA-based platform that can be applied to paraffin-embedded tissue will also be developed. It will incorporate the essential information of the microarray platform and allow the assessment of critical parameters in specimens not specifically collected for microarray analysis, hence greatly expanding the utility of the information. There is evidence that genetic data may provide additional prognostic information to the current gene expression-derived prognosticators. We propose to obtain comprehensive, high-resolution molecular genetic data on diffuse large B-cell lymphoma to examine if the combination of genetic and gene expression parameters will improve the current prognostic model. Since existing prognosticators were derived from the study of archival cases prior to the availability of anti-CD20 therapy, they will be re-evaluated in patients treated with current therapeutic regimens. Modifications will be made to maintain the accuracy of the prognosticators. This study will not only validate previously-defined diagnostic and prognostic signatures, but will further refine the signatures and algorithms for higher accuracy and robustness. The range of application will be expanded by adapting the information to a Q-RT-PCR platform. Prognosticators will be enhanced by the incorporation of genetic data, and updated by a re-evaluation of cohorts of patients treated with current therapeutic regimens.
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Clinical Trials Research
For current Clinical Trials information at the BC Cancer Agency, please visit the Clinical Trials website.