1/7. ring chromosomes in a malignant mesenchymoma.We report, for the first time, the cytogenetic and molecular genetic constitution of a human mesenchymoma. As in several other soft tissue sarcomas, supernumerary ring and rod-shaped marker chromosomes were observed next to an otherwise normal diploid karyotype. Comparative genomic in situ hybridization and whole chromosome painting experiments revealed that chromosome 1q21-q25 and 12q14-q15 sequences were amplified, and that these sequences resided on the supernumerary marker chromosomes. We assume that, in this malignant mesenchymoma, the observed chromosomal anomalies may be associated with its well differentiated liposarcomatous component.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/7. Orbital chondrosarcoma developing in a patient with Paget disease.PURPOSE: To describe the radiologic, histopathologic, and cytogenetic features of an orbital chondrosarcoma developing in a patient with Paget disease. methods: A 64-year-old woman presented with rapidly progressive proptosis of her right eye. Computed tomographic scans, histopathologic examination, and cytogenetic analysis were performed. RESULTS: Computed tomographic scans disclosed osseous changes of the temporal and frontal bones, with areas of high density consistent with Paget disease. A soft-tissue tumor in the right lateral orbital wall was consistent with Paget sarcoma. On histology, a chondrosarcoma was diagnosed, which was confirmed by fluorescent in situ hybridization. CONCLUSION: This is a unique case of orbital chondrosarcoma developing in a patient with Paget disease.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/7. Molecular genetic characterization of both components of a dedifferentiated chondrosarcoma, with implications for its histogenesis.Dedifferentiated chondrosarcoma is defined as a high-grade, anaplastic sarcoma adjacent to a low-grade malignant cartilage-forming tumour. Controversy remains as to whether the anaplastic and cartilaginous components are derived from a common precursor cell, or whether they represent separate genotypic lineages (collision tumour). Both components of a case of dedifferentiated chondrosarcoma were therefore separately investigated by loss of heterozygosity (LOH) analysis, comparative genomic hybridization (CGH), dna flow cytometry, and p53 analysis. Both showed p53 overexpression and an identical somatic 6 bp deletion in exon 7 of p53. Combination of the CGH and LOH results revealed that both components had lost the same copy of chromosome 13. These results provide compelling evidence in this case for a common origin, instead of the 'collision tumour' theory. Certain genotypic alterations were not shared. The anaplastic component showed severe aneuploidy, LOH at additional loci, and amplification and deletion of several chromosome parts. In contrast, the cartilaginous component had lost chromosomes 5, 22, 17p and part of 16p and revealed an amplification of 17q. The LOH and CGH results further demonstrated that the two components had lost a different copy of chromosome 4. Thus, a substantial number of genetic alterations have occurred after the diversion of the two components, indicating that the separation of the two clones, derived from a single precursor, was a relatively early event in the histogenesis of this case of dedifferentiated chondrosarcoma.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/7. Coexpression of NOR1 and SIX3 proteins in extraskeletal myxoid chondrosarcomas without detectable NR4A3 fusion genes.Extraskeletal myxoid chondrosarcoma (EMC) is a rare mesenchymal tumor cytogenetically characterized by reciprocal translocations, such as t(9;22)(q22;q12) and t(9;17)(q22;q11), which result in EWSR1/NR4A3 and TAF15/NR4A3 fusion genes (alias EWS/NOR1, TAF2N/NOR1), respectively. NOR1 is an orphan nuclear receptor and acts as a transcription factor that can bind to its putative coactivator, SIX3. Although the NOR1 fusion protein has been implicated in oncogenesis of EMC, a small fraction of EMC lacks detectable rearrangements of the NR4A3 gene or 9q22. We report a case of EMC with no detectable NR4A3 gene alterations, as assessed with various molecular techniques including reverse transcription-polymerase chain reaction (RT-PCR), Southern blotting, interphase fluorescence in situ hybridization, and PCR single-strand conformation polymorphism-but with coexpression of native NOR1 and SIX3. In our survey of another 18 EMCs, we identified one more case expressing both NOR1 and SIX3 but lacking NR4A3 fusion. Fourteen tumors with detectable NR4A3 fusion genes (EWSR1-NR4A3; TAF15-NR4A3) expressed neither native NOR1 nor SIX3. SIX3 expression is normally confined specifically to the developing eye and fetal forebrain, although the expression of NR4A3 is largely ubiquitous. Our data suggest that aberrant coexpression of NOR1 and SIX3 is a potential alternative mechanism underlying the development of EMC.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/7. Extraskeletal myxoid chondrosarcoma of the jugular foramen.OBJECTIVE: To report a case of an extraskeletal myxoid chondrosarcoma (EMC) arising from the jugular foramen. EMCs are tumors usually seen in the deep soft tissues of the extremities and are rarely seen within the intracranial cavity. The histological differential diagnosis includes chordoma, conventional chondrosarcoma and chordoid meningioma, among others. A distinguishing feature of EMC is their characteristic reciprocal translocation t(9;22)(q22;q12). MATERIAL: A 63-year-old man presented with progressive hearing loss and gait imbalance. magnetic resonance imaging showed a heterogeneously enhancing 2.4 cm mass in the cerebellopontine angle. A right far lateral transcondylar skull base approach with gross total removal of the tumor was performed. Intraoperative findings showed that the mass appeared to arise from the glossopharyngeal nerve within the jugular foramen. METHOD: histology, immunohistochemistry, and fluorescence in situ hybridization studies were performed. RESULTS: Histological and immunohistochemical studies were compatible with the diagnosis of EMC. fluorescence in situ hybridization studies showed disruption of the EWS gene locus at 22q12 and added further support to the diagnosis. CONCLUSIONS: We report a rare case of EMC arising from the jugular foramen, and the diagnosis of EMC can be supported by confirmation of disruption of the EWS gene locus.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
6/7. Molecular analysis of a myxoid chondrosarcoma with rearrangements of chromosomes 10 and 22.Myxoid chondrosarcoma is a rare tumor of adulthood. An associated nonrandom reciprocal translocation between chromosome 9 and 22 was previously reported in this tumor. We performed cytogenetic and molecular genetic analysis of a myxoid chondrosarcoma derived from the sphenoid bone. Using restriction fragment length polymorphism (RFLP) analysis, we demonstrated rearrangement and a possible allele loss close to the chromosome 22 breakpoint. In addition, structural rearrangement in the chromosome 10q21.1 region and an allele loss in the chromosome 10q21-q23 region were also detected. In tumor dna an additional hybridization fragment was detected by pAS-1 probe, which recognizes multiple pseudogenes of argininosuccinate synthetase dispersed in various chromosomes. We were unable to detect chromosomal abnormalities with two additional chromosome 9q probes. This study suggests that multiple gene rearrangements occurred in the myxoid chondrosarcoma and the significance of this is discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/7. Evidence of an association between 6q13-21 chromosome aberrations and locally aggressive behavior in patients with cartilage tumors.BACKGROUND: The finding of a cytogenetic-pathologic correlation between complex karyotypes and high grade cartilaginous tumors has been reported. However, few cytogenetic reports exist regarding benign or low grade lesions. A subset of low grade malignant cartilaginous tumors is characterized by locally aggressive behavior but no metastatic potential. Because the histopathologic distinction between benign, borderline, or low grade malignant cartilaginous lesions can be difficult, the finding of additional tumor markers associated with the clinical behavior of borderline cartilaginous lesions could be clinically significant. methods: Four cartilaginous tumors, including an osteochondroma (OC), a chondromyxoid fibroma (CF), an enchondroma (EC), and a dedifferentiated chondrosarcoma (DCS), were cultured and harvested using short term, in situ culture techniques. Chromosome analysis was performed by conventional G-banding and fluorescence in situ hybridization was used to confirm G-banding. RESULTS: The stemlines of all four tumors showed multiple chromosome anomalies that included aberrations of 6q13-21. The OC showed a t(6;16)(q21;p13.3). The CF showed a complex rearrangement between the chromosome 6 homologues, resulting in an inv(6)(p25q23)t(6;6)(q23;q13). This tumor also showed the clonal evolution of telomeric associations resulting in duplications, deletions, and the formation of a ring 15. The EC showed a der(6)t(6;15)(q13;q11)t(15;22)(q22;q13) stemline and subclones with an unstable iso 17q that subsequently fused to both ends of chromosome 16. The DCS showed a del(6)(q13), r(9), 12 stemline. CONCLUSIONS: The cytogenetic findings of this study suggest the cytogenetic-pathologic correlation of complex karyotypes found in high grade cartilage tumors may extend to lower grade tumors with complex karyotypes. These findings further suggest that chromosome aberrations in the region of 6q13-21 may be associated with locally aggressive behavior in patients with cartilage tumors.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |