| 1. |
- Downs-Kelly, Erinn, et al.
(författare)
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The utility of fluorescence in situ hybridization (FISH) in the diagnosis of myxoid soft tissue neoplasms
- 2008
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Ingår i: American Journal of Surgical Pathology. - 1532-0979. ; 32:1, s. 8-13
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Tidskriftsartikel (refereegranskat)abstract
- Diagnosing myxoid soft tissue neoplasms can be challenging because of overlapping histologic features. Distinct chromosomal translocations have been identified in several myxoid sarcomas, including t(12;16)(q13;p11) FUS-DDIT3 in myxoid liposarcoma, t(7,-16)(q34;p11) FUS-CREB3L2 in low-grade fibromyxoid sarcoma, and t(9;22)(q31;q12) EWSRINR4A3 in extraskeletal myxoid chondrosarcoma. These recurrent chromosomal alterations are attractive targets for diagnostic studies. To that end, dual-color, break-apart fluorescence in situ hybridization (FISH) probes spanning the genomic regions of EWSRI (22q12), DDIT3 (12q13), and FUS (16p11) (Vysis, Downer's Grove, IL) were evaluated in formalin-fixed, paraffin-embedded tissues from myxoid neoplasms, including intramuscular myxoma (it 10), myxoid liposarcoma (n = 18) low-grade fibromyxoid sarcoma (n = 10), extraskeletal myxoid chondrosarcoma (n = 13), and myxofibrosarcoma (n = 8). Of the myxoid liposarcomas, 18/18 cases had a rearrangement of the DDIT3 gene, with 17/18 (94.4%) showing both DDIT3 and FUS gene rearrangements. A FUS gene rearrangement was identified in 7/10 (70%) of lowgrade fibromyxoid sarcomas, with no changes involving EWSRI or DDIT3. An EWSRI translocation was seen in 6/13 (46.2%) of extraskeletal myxoid chondrosarcomas, without changes in DDIT3 or FUS genes. The remaining neoplasms studied showed no rearrangements involving DDIT3, FUS, or EWSRI genes. In conclusion, interphase FISH using DDIT3 and FUS probes identifies the characteristic translocation in myxoid liposarcoma. FUS and EWSRI probes are useful in confirming the diagnosis of low-grade fibromyxoid sarcoma and extraskeletal myxoid chondrosarcoma, respectively. The specificity of the probes is documented as none of the non-translocation-associated myxoid tumors showed genomic abnormalities with the probes tested. FISH is capable of providing specific ancillary information useful in this often difficult differential diagnosis.
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| 2. |
- Mertens, Fredrik, et al.
(författare)
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Clinicopathologic and molecular genetic characterization of low-grade fibromyxoid sarcoma, and cloning of a novel FUS/CREB3L1 fusion gene
- 2005
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Ingår i: Laboratory Investigation. - : Elsevier BV. - 1530-0307 .- 0023-6837. ; 85:3, s. 408-415
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Tidskriftsartikel (refereegranskat)abstract
- Low-grade fibromyxoid sarcoma (LGFMS) is an indolent, late-metastasizing malignant soft-tissue tumor that is often mistaken for either more benign or more malignant tumor types. Cytogenetic analyses have identified a recurrent balanced translocation t(7;16) (q32-34;p11), later shown by molecular genetic approaches to result in a FUS/CREB3L2 fusion gene. Whereas preliminary studies suggest that this gene rearrangement is specific for LGFMS, its incidence in this tumor type and the possible existence of variant fusion genes have not yet been addressed. For this purpose, a series of potential LGFMS were obtained from nine different soft-tissue tumor centres and subjected to molecular analysis as well as careful histopathologic review. Reverse transcriptase-polymerase chain reaction analysis disclosed a FUS/CREB3L2 fusion transcript in 22 of the 23 (96%) cases that remained classified as LGFMS after the histologic re-evaluation and from which RNA of sufficient quality could be extracted, whereas none of the cases that were classified as other tumor types was fusion-positive. In one of the tumors with typical LGFMS appearance, we found that FUS was fused to the CREB3L1 gene instead of CREB3L2. The proteins encoded by these genes both belong to the same basic leucine-zipper family of transcription factors, and display extensive sequence homology in their DNA-binding domains. Thus, it is expected that the novel FUS/CREB3L1 chimera will have a similar impact at the cellular level as the much more common FUS/CREB3L2 fusion protein. Taken together, the results indicate that virtually all LGFMS are characterized by a chimeric FUS/CREB3L2 gene, and that rare cases may display a variant FUS/CREB3L1 fusion.
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