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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The t(4;14) translocation occurs in 25% of multiple myeloma (MM) and results in both the ectopic expression of fibroblast growth factor receptor 3 (FGFR3) from der4 and immunoglobulin heavy chain-MMSET hybrid messenger RNA transcripts from der14. The subsequent selection of activating mutations of the translocated FGFR3 by MM cells indicates an important role for this signaling pathway in tumor development and progression. To investigate the mechanism by which FGFR3 overexpression promotes MM development, interleukin-6 (IL-6)-dependent murine B9 cells were transduced with retroviruses expressing functional wild-type or constitutively activated mutant FGFR3. Overexpression of mutant FGFR3 resulted in IL-6 independence, decreased apoptosis, and an enhanced proliferative response to IL-6. In the presence of ligand, wild-type FGFR3-expressing cells also exhibited enhanced proliferation and survival in comparison to controls. B9 clones expressing either wild-type FGFR3 at high levels or mutant FGFR3 displayed increased phosphorylation of STAT3 and higher levels of bcl-x(L) expression than did parental B9 cells after cytokine withdrawal. The mechanism of the enhanced cell responsiveness to IL-6 is unknown at this time, but does not appear to be mediated by the mitogen-activated protein kinases SAPK, p38, or ERK. These findings provide a rational explanation for the mechanism by which FGFR3 contributes to both the viability and propagation of the myeloma clone and provide a basis for the development of therapies targeting this pathway.
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PMID:Ectopic expression of fibroblast growth factor receptor 3 promotes myeloma cell proliferation and prevents apoptosis. 1064 14

The immunoglobulin (Ig) genes are frequently involved in chromosomal rearrangements with a wide variety of partner loci in multiple myeloma (MM). However, several partner chromosomes have not been detected by conventional cytogenetic methods; for example, 4p16.3 (FGFR3), 6p25.3 (IRF4), and 16q23 (c-maf). To clarify the incidence of t(4;14)(p16.3;q32.3) in primary tumors of MM and to evaluate possible correlations with specific manifestations of the disease, G-banding, double-color fluorescence in situ hybridization (DC-FISH), and/or reverse-transcriptase polymerase chain reaction (RT-PCR) were performed on 40 patients with MM-two with plasmacytoma (PCM) and three with plasma cell leukemia (PCL). All patients were studied by DC-FISH; 40 were studied by G-banding and 36 were studied by RT-PCR. The FISH probes consisted of a cosmid pC385.12 containing the FGFR3 gene, a YAC Y6 containing VH, and a phage Iggamma1-10 containing the gamma1 constant region (Cgamma). We identified eight patients with either FGFR3/Cgamma fusion or FGFR3 overexpression: six patients with both FGFR3/Cgamma fusion and FGFR3 overexpression, one patient with FGFR3/Cgamma, and one with FGFR3 overexpression. FGFR3/Cgamma fusion was demonstrated at a frequency of 19% to 38% on interphase nuclei in seven of the 45 patients. Lytic bone lesions were found to be associated with FGFR3 overexpression. Interphase FISH with FGFR3 and Cgamma probes combined with RT-PCR proved to be an effective tool for detection of this fully cryptic translocation, thus facilitating the characterization of clinical features of MM patients with t(4;14).
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PMID:Interphase detection of t(4;14)(p16.3;q32.3) by in situ hybridization and FGFR3 overexpression in plasma cell malignancies. 1070 76

A patient with multiple myeloma had an automated blood count performed on a Coulter STK-S counter that repeatedly failed internal limits for both mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The calculated hematocrit agreed with a spun hematocrit, suggesting that the hemoglobin concentration was being overestimated by the automated counter. Measurement of the plasma hemoglobin concentration of the sample, which showed no visible hemolysis, gave a hemoglobin concentration of 32 g/L on the STK-S analyzer. Correction of the whole blood hemoglobin using the plasma hemoglobin gave a value consistent with the hematocrit. The corrected mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration values were within standard limits. This patient's paraprotein was characterized as IgA-kappa and was present at a concentration of 61 g/L. The hemoglobin concentration measured on whole blood by Sysmex NE 8000 and Technicon H*1E autoanalyzers agreed reasonably well with the corrected result from the STK-S.
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PMID:Overestimation of hemoglobin in a patient with an IgA-kappa monoclonal gammopathy. 1074 23

Vascular endothelial growth factor (VEGF), a multifunctional cytokine, potently stimulates angiogenesis including tumor neovascularization. Although well established in solid tumors, the role of VEGF in bone marrow neoangiogenesis and paracrine tumor-stromal cell interactions in lymphohematopoietic malignancies has not been fully elucidated. In multiple myeloma (MM), marrow neovascularization parallels disease progression. This parallel prompted us to investigate the expression and secretion of VEGF by myeloma cells and its potential effects in myeloma-marrow stroma interactions. The biologically active splice variants VEGF165 and VEGF121 were expressed and secreted by myeloma cell lines and plasma cells isolated from the marrow of patients with MM. As shown by immunocytochemistry or RT-PCR, myeloma cells did not express or weakly expressed the VEGF receptors FLT-1 and FLK-1/KDR, indicating that autocrine stimulation is unlikely. In contrast, FLK-1/KDR was abundantly expressed by marrow stromal cells. Therefore, we studied the effects of VEGF on marrow stroma, focusing on the secretion of interleukin-6 (IL-6), a potent growth factor for myeloma cells and an inhibitor of plasma cell apoptosis. Exposure of stromal and microvascular endothelial cells to recombinant human (rh) VEGF165 or VEGF121 induced a time- and dose-dependent increase in IL-6 secretion (14- to 27-fold at 50 ng/mL after 24 hours, P <.001). Conversely, rhIL-6 stimulated VEGF expression and secretion in myeloma cell lines (40%-60%; P <.05) and to a variable degree (up to 5.3-fold; P <.005) in plasma cells purified from the marrow of patients with MM. This mutual stimulation suggests paracrine interactions between myeloma and marrow stromal cells triggered by VEGF and IL-6. (Blood. 2000;95:2630-2636)
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PMID:Vascular endothelial growth factor and interleukin-6 in paracrine tumor-stromal cell interactions in multiple myeloma. 1075 44

The fibroblast growth factor receptor (FGFR) family members mediate a number of important cellular processes, and are mutated or overexpressed in several forms of human cancer. Mutation of Lys650-->Glu in the activation loop of the FGFR3 kinase domain causes the lethal human skeletal disorder thanatophoric dysplasia type II (TDII) and is also found in patients with multiple myeloma, bladder and cervical carcinomas. This mutation leads to constitutive activation of FGFR3. To compare the signaling activity of FGFR family members, this activating mutation was generated in FGFR1, FGFR3, and FGFR4. We show that the kinase domains of FGFR1, FGFR3, and FGFR4 containing the activation loop mutation, when targeted to the plasma membrane by a myristylation signal, can transform NIH3T3 cells and induce neurite outgrowth in PC12 cells. Phosphorylation of Shp2, PLC-gamma, and MAPK was also stimulated by all three 'TDII-like' FGFR derivatives. Additionally, activation of Stat1 and Stat3 was observed in cells expressing the activated FGFR derivatives. Finally, we demonstrate that FGFR1, FGFR3, and FGFR4 derivatives can stimulate PI-3 kinase activity. Our comparison of these activated receptor derivatives reveals a significant overlap in the panel of effector proteins used to mediate downstream signals. This also represents the first demonstration that activation of FGFR4, in addition to FGFR1 and FGFR3, can induce cellular transformation. Moreover, our results suggest that Stat activation by FGFRs is important in their ability to act as oncogenes.
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PMID:Transformation and Stat activation by derivatives of FGFR1, FGFR3, and FGFR4. 1091 87

We and others have recently identified a novel recurring t(4;14)(p16.3; q32) translocation in multiple myeloma (MM) that leads to an apparent deregulation of the FGFR3 and WHSC1/MMSET genes. Because the presence of IGH-MMSET hybrid transcripts has been found in MM cell lines with t(4;14), they may represent a specific tumor-associated marker in MM. In this study, we developed a reverse transcription-PCR (RTPCR) assay for detecting chimeric transcripts from all of the 4p16.3 breakpoints identified thus far, and we used it to investigate a representative panel of 53 MM patients and 16 patients with monoclonal gammopathy of uncertain significance; in addition, t(4;14) was investigated in all of the MM patients by means of two-color fluorescence in situ hybridization. IGH-MMSET transcripts were found in 11 of the 53 (20%) MM cases and 1 of 16 (6%) cases of monoclonal gammopathy of uncertain significance. There was complete concordance between the RT-PCR and fluorescence in situ hybridization analyses of the MM cases. The results of this study indicate that RT-PCR is a sensitive and reliable method of detecting t(4;14) and suggest that it may be useful for monitoring the disease in a significant proportion of patients.
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PMID:Detection of t(4;14)(p16.3;q32) chromosomal translocation in multiple myeloma by reverse transcription-polymerase chain reaction analysis of IGH-MMSET fusion transcripts. 1094 9

Anti-HER2/neu therapy of human HER2/neu-expressing malignancies such as breast cancer has shown only partial success in clinical trials. To expand the clinical potential of this approach, we have genetically engineered an anti-HER2/neu IgG3 fusion protein containing GM-CSF. Anti-HER2/neu IgG3-(GM-CSF) expressed in myeloma cells was correctly assembled and secreted. It was able to target HER2/neu-expressing cells and to support growth of a GM-CSF-dependent murine myeloid cell line, FDC-P1. The Ab fusion protein activated J774.2 macrophage cells so that they exhibit an enhanced cytotoxic activity and was comparable to the parental Ab in its ability to effect Ab-dependent cellular cytotoxicity-mediated tumor cell lysis. Pharmacokinetic studies showed that anti-HER2/neu IgG3-(GM-CSF) is stable in the blood. Interestingly, the half-life of anti-HER2/neu IgG3-(GM-CSF) depended on the injected dose with longer in vivo persistence observed at higher doses. Biodistribution studies showed that anti-HER2/neu IgG3-(GM-CSF) is mainly localized in the spleen. In addition, anti-HER2/neu IgG3-(GM-CSF) was able to target the HER2/neu-expressing murine tumor CT26-HER2/neu and enhance the immune response against the targeted Ag HER2/neu. Anti-HER2/neu IgG3-(GM-CSF) is able to enhance both Th1- and Th2-mediated immune responses and treatment with this Ab fusion protein resulted in significant retardation in the growth of s.c. CT26-HER2/neu tumors. Our results suggest that anti-HER2/neu IgG3-(GM-CSF) fusion protein is useful in the treatment of HER2/neu-expressing tumors.
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PMID:Recombinant anti-human HER2/neu IgG3-(GM-CSF) fusion protein retains antigen specificity and cytokine function and demonstrates antitumor activity. 1104 42

Multiple myeloma (MM) is a B-cell neoplasm characterized by bone marrow infiltration with malignant plasma cells, which synthesize and secrete monoclonal immunoglobulin (Ig) fragments. Despite the considerable progress in the understanding of MM biology, the molecular basis of the disease remains elusive. The initial transformation is thought to occur in a postgerminal center B-lineage cell, carrying a somatically hypermutated Ig heavy chain (IGH) gene. This plasmablastic precursor cell colonizes the bone marrow, propagates clonally and differentiates into a slowly proliferating myeloma cell population, all under the influence of specific cell adhesion molecules and cytokines. Production of interleukin-6 by stromal cells, osteoblasts and, in some cases, neoplastic cells is an essential element of myeloma cell growth, with the cytokine stimulus being delivered intracellularly via the Jack-STAT and ras signaling pathways. While karyotypic changes have been identified in up to 50% of MM patients, recent molecular cytogenetic techniques have revealed chromosomal abnormalities in the vast majority of examined cases. Translocations mostly involve illegal switch rearrangements of the IGH locus with various partner genes (CCND1, FGFR3, c-maf). Such events have been assigned a critical role in MM development. Mutations in coding and regulatory regions, as well as aberrant expression patterns of several oncogenes (c-myc, ras) and tumor suppressor genes (p16, p15) have been reported. Key regulators of programmed cell death (BCL-2, Fas), tumor expansion (metalloproteinases) and drug responsiveness (topoisomerase II alpha) have also been implicated in the pathogenesis of this hematologic malignancy. A tumorigenic role for human herpesvirus 8 (HHV8) was postulated recently, following the detection of viral sequences in bone marrow dendritic cells of MM patients. However, since several research groups were unable to confirm this observation, the role of HHV8 remains unclear. Translation of the advances in MM molecular biology into novel therapeutic strategies is essential in order to improve disease prognosis.
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PMID:Molecular aspects of multiple myeloma. 1110 9

The t(4;14) translocation occurs frequently in multiple myeloma (MM) and results in the simultaneous dysregulated expression of 2 potential oncogenes, FGFR3 (fibroblast growth factor receptor 3) from der(14) and multiple myeloma SET domain protein/Wolf-Hirschhorn syndrome candidate gene 1 from der(4). It is now shown that myeloma cells carrying a t(4;14) translocation express a functional FGFR3 that in some cases is constitutively activated by the same mutations that cause thanatophoric dysplasia. As with activating mutations of K-ras and N-ras, which are reported in approximately 40% of patients with MM, activating mutations of FGFR3 occur during tumor progression. However, the constitutive activation of ras and FGFR3 does not occur in the same myeloma cells. Thus the activated forms of these proteins appear to share an overlapping role in tumor progression, suggesting that they also share the signaling cascade. Consistent with this prediction, it is shown that activated FGFR3-when expressed at levels similar to those seen in t(4;14) myeloma-is an oncogene that acts through the MAP kinase pathway to transform NIH 3T3 cells, which can then generate tumors in nude mice. Thus, FGFR3, when overexpressed in MM, may be not only oncogenic when stimulated by FGF ligands in the bone marrow microenvironment, but is also a target for activating mutations that enable FGFR3 to play a ras-like role in tumor progression.
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PMID:Activated fibroblast growth factor receptor 3 is an oncogene that contributes to tumor progression in multiple myeloma. 1151 Apr 69

Primary plasma cell leukaemia (P-PCL) is a variant of multiple myeloma (MM) first diagnosed in the leukemic phase, with >2000/mm(3) circulating plasma cells (PCs) and plasmacytosis >20% of the white cell count. We investigated the clinical characteristics, therapy, immunophenotype and prognosis factors of 18 patients. Common features at diagnosis were asthenia (seven patients), renal insufficiency (ten patients), bone pain (seven patients), splenomegaly or hepatomegaly (five patients). Hypercalcemia was present at diagnosis in seven patients and was the most potent poor prognosis factor (P<0.05). Most patients (16 out of 18) were treated with an anthracyclin containing regiment; complete remission was attained in one patient and partial remission in 11 patients while six patients had no response. The median survival time from diagnosis was 7 months (2--12, 95% confidence interval), but response to treatment had favorable predictive value (P<0.05). The PCs were usually positive for mature B-cell markers (PCA-1, CD38). They expressed integrins which may increase their binding to endothelial cells and thus participate in PCL physiopathology by favoring plasmocyte extramedullary spread.
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PMID:Primary plasma cell leukaemia: a report of 18 cases. 1116 24


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