Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MUM1/IRF4 is a myeloma-associated oncogene transcriptionally activated as a result of t(6;14)(p25,q32) chromosomal translocation and by virtue of its juxtaposition to the immunoglobulin heavy chain gene (IgH) locus. When this oncogene becomes non-functional, no activated B/T lymphocytes and Ig secreting plasma cells are observed, suggesting that MUM1/IRF4 is crucial for lymphoid development. Its expression was analyzed in both reactive lymphoid and lymphoma tissues by means of an immunohistochemical technique using specific goat antiserum against MUM1/IRF4. This analysis detected a 50 kDa MUM1 product whose localization was restricted to the nuclei of the lymphocytes. The MUM1+ cells in reactive lymph nodes were found to consist of plasma cells and a small fraction (approximately 7.9%) of B cells harboring CD20+CD38+, which were located in the light zone of the germinal center. MUM1 expression in peripheral blood B/T lymphocytes was upregulated by mitogenic stimuli, suggesting that MUM1 positivity represents the activated state of the B/T cells. In B cell non-Hodgkin's lymphoma (NHL), MUM1 expression was observed in 73.2% (30/41) of diffuse large B cell lymphoma (DLBCL), 20% (1/5) of marginal zone lymphoma (MZL) and 43% (3/7) of small lymphocytic lymphoma (SLL) cases, whereas it was not seen in any cases of mantle cell lymphoma (MCL) or follicle center lymphoma (FCL). Also, MUM1 was stained at high intensity in various types of T cell lymphomas including adult T cell leukemia/lymphoma (ATL/L) and anaplastic large cell lymphoma (ALCL) and in the majority of Hodgkin's diseases. Our results suggest that a major proportion of lymphomas comprise either physiologically or aberrantly activated neoplastic lymphocytes expressing the MUM1 protein.
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PMID:MUM1/IRF4 expression as a frequent event in mature lymphoid malignancies. 1072 Jan 41

Diffuse large B-cell lymphoma (DLBCL) comprises a diverse group of neoplasms that have recently been subdivided by gene expression profiling and immunohistochemical studies into at least 2 subgroups [germinal center (GC) type and non-GC type]. The non-GC subtype has a post-GC activated phenotype and typically expresses MUM1 by immunohistochemistry. We hypothesized that MUM1 may be dysregulated/up-regulated in these tumors by a chromosomal translocation, as is seen in many cases of plasma cell myeloma [where MUM1 is juxtaposed with the immunoglobulin heavy chain gene (IgH)]. Therefore, using a novel MUM1 break-apart probe constructed in our laboratory, we performed fluorescence in situ hybridization on 33 cases of DLBCL (17 GC type and 16 non-GC type) for a MUM1 translocation. We identified 1 case of a MUM1 translocation out of 31 cases with successful fluorescence in situ hybridization. This case was a non-GC DLBCL (1/15). We conclude that genetic abnormalities involving MUM1 are rare in DLBCL and that a mechanism of deregulation of the MUM1 protein other than by a translocation event is involved in the majority of non-GC cases.
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PMID:Translocations involving MUM1 are rare in diffuse large B-cell lymphoma. 1881 67