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Chromosome translocations in multiple myeloma
1Department of Medicine, Division of Hematology and Oncology, Weill Medical College of Cornell University, New York, NY, USA. plbergsa@med.cornell.edu
Oncogene
|October 19, 2001
Summary
Multiple myeloma (MM) development involves genetic translocations in plasma cells (PC). These IgH translocations, increasing with disease stage, drive proliferation and inhibit differentiation, leading to malignant transformation.
Area of Science:
- Hematology
- Oncology
- Cancer Genetics
Background:
- Multiple myeloma (MM) is a cancer of plasma cells (PC), often originating from Monoclonal Gammopathy of Undetermined Significance (MGUS).
- The disease progresses from bone marrow involvement to extramedullary stages, with increasing genetic complexity.
- Immunoglobulin heavy chain (IgH) translocations are key genetic events in MM pathogenesis.
Purpose of the Study:
- To investigate the role and incidence of IgH translocations in the progression of multiple myeloma.
- To identify common chromosomal partners involved in primary IgH translocations.
- To understand the mechanism by which these translocations contribute to plasma cell transformation.
Main Methods:
- Analysis of IgH translocations in different stages of MM, from MGUS to MM cell lines.
- Identification of chromosomal partners involved in primary and secondary translocations.
- Examination of the functional consequences of dysregulated oncogenes in MM pathogenesis.
Main Results:
- The incidence of IgH translocations increases significantly with disease progression (50% in MGUS to >90% in MM cell lines).
- Four main chromosomal partners (11q13, 6p21, 4p16, 16q23) account for most primary IgH translocations, often mediated by errors in IgH switch recombination.
- Secondary translocations, like those involving 8q24 (c-myc), are associated with tumor progression and are not B-cell specific DNA modification errors.
- Dysregulated oncogenes primarily increase proliferation and/or inhibit differentiation, rather than conferring anti-apoptotic effects.
Conclusions:
- Primary IgH translocations are early, immortalizing events in MM development, driven by B-cell specific DNA modification errors.
- Secondary translocations contribute to tumor progression.
- The observed oncogene dysregulation suggests a common cellular fate for transformed plasma cells, emphasizing proliferation and blocked differentiation.