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

Dysregulation of oncogenes by translocation to the IgH locus (14q32) is a seminal event in the pathogenesis of B-cell tumours. In multiple myeloma (MM), translocations to the IgH locus have been reported at an incidence of 20-60%. For most translocations, the partner chromosome is unknown (14q+); for the others, a diverse array of chromosomal partners have been identified, with 11q13 (cyclin D1) the only chromosome that is frequently involved. Recently, we developed a Southern-blot assay that detects translocation breakpoint fragments in most MM tumours, including those with no translocation detected by conventional karyotyping. In a continuing analysis of translocation in 21 myeloma cell lines and primary tumours, we show that the novel, karyotypically silent translocation t(4;14)(p16.3;q32.3) is present in five lines and at least three of ten primary tumours. The chromosome-4 breakpoints are clustered in a 70-kb region centromeric to the fibroblast growth factor receptor 3 gene (FGFR3), the apparent dysregulated oncogene. Two lines and one primary tumour with this translocation selectively express an FGFR3 allele containing activating mutations identified previously in thanatophoric dwarfism. We propose that after the t(4;14) translocation, somatic mutation during tumour progression frequently generates in FGFR3 protein that is active in the absence of ligand.
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PMID:Frequent translocation t(4;14)(p16.3;q32.3) in multiple myeloma is associated with increased expression and activating mutations of fibroblast growth factor receptor 3. 920 91

The t(4;14)(p16;q32) translocation, found in 15% of multiple myeloma (MM) cases, indicates a poor prognosis. Plasma cells (PC) with t(4;14) ectopically express the fibroblast growth factor receptor 3 (FGFR3) tyrosine kinase receptor, which has potential transforming activity and may represent a therapeutic target. To detect FGFR3 protein expression, bone marrow (BM) aspirate from 200 consecutive newly diagnosed (n = 116) or relapsing (n = 74) MM patients was studied by flow cytometry (FC) using anti-CD138 and anti-FGFR3 antibodies. FC data was compared to real time quantitative-polymerase chain reaction (RQ-PCR) of the IGH-MMSET and FGFR3 transcripts. An IGH-MMSET transcript was found in 24/200 patients (12%). In 20 of these, FC detected CD138(+)/FGFR3(+) cells. No expression of FGFR3 was detected in the 4 FGFR3(-) cases by RQ-PCR. FGFR3 was never expressed on PC without t(4;14). Circulating PC (CPC) were detected in patients with (11/11) and patients without (13/41) t(4;14). In 2/8 t(4;14) cases studied longitudinally, coexisting FGFR3(+) and FGFR3(-) CPC were observed. Fluorescent in situ hybridisation (FISH) analysis of the FGFR3(-) subclones showed deletion of the der(14) in one patient. In conclusion, as a supplemental method to RQ-PCR or FISH, FC analysis of FGFR3 expression is a reliable and routinely available method for the detection and management of new therapeutic approaches of t(4;14) MM.
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PMID:Detection and follow-up of fibroblast growth factor receptor 3 expression on bone marrow and circulating plasma cells by flow cytometry in patients with t(4;14) multiple myeloma. 1722 17

FGFR3 is frequently activated by mutation in urothelial carcinoma (UC) and represents a potential target for therapy. In multiple myeloma, both over-expression and mutation of FGFR3 contribute to tumour development. To define the population of UC patients who may benefit from FGFR-targeted therapy, we assessed both mutation and receptor over-expression in primary UCs from a population of new patients. Manual or laser capture microdissection was used to isolate pure tumour cell populations. Where present, non-invasive and invasive components in the same section were microdissected. A screen of the region of the highest tumour stage in each sample yielded a mutation frequency of 42%. Mutations comprised 61 single and five double mutations, all in hotspot codons previously identified in UC. There was a significant association of mutation with low tumour grade and stage. Subsequently, non-invasive areas from the 43 tumours with both non-invasive and invasive components were analysed separately; 18 of these had mutation in at least one region, including nine with mutation in all regions examined, eight with mutation in only the non-invasive component and one with different mutations in different regions. Of the eight with mutation in only the non-invasive component, six were predicted to represent a single tumour and two showed morphological dissimilarity of fragments within the block, indicating the possible presence of distinct tumour clones. Immunohistochemistry showed over-expression of FGFR3 protein in many tumours compared to normal bladder and ureteric controls. Increased expression was associated with mutation (85% of mutant tumours showed high-level expression). Overall, 42% of tumours with no detectable mutation showed over-expression, including many muscle-invasive tumours. This may represent a non-mutant subset of tumours in which FGFR3 signalling contributes to the transformed phenotype and which may benefit from FGFR-targeted therapies.
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PMID:FGFR3 protein expression and its relationship to mutation status and prognostic variables in bladder cancer. 1766 22