Cases reported "Chromosome Aberrations"

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1/12. Chromosomal imbalances in gastric cancer. Correlation with histologic subtypes and tumor progression.

    dna copy number changes were analyzed by comparative genomic hybridization (CGH) in 38 gastric carcinomas and correlated with tumor histologic type and progression. Gains of copy numbers were observed in all tumors, affecting all chromosomes except chromosome 16. The average number of copy number gains was 7 (range, 1-13), most frequently located on chromosomes 11, 12, 15, 17, and 20 in 45% to 97% of tumors. High-level amplifications were found on chromosomes 12, 15, 17, and 20; the latter was affected most frequently (66%). Loss of dna copy numbers was detected in 14 tumors affecting 7 chromosomes. No statistically significant differences in the frequency and pattern of chromosomal imbalances were observed in tumor histologic type (Lauren classification) and grade of differentiation, as well as the prognostic parameters depth of invasion (pT) and lymph node involvement (pN). Our results indicate that in gastric cancer there is no specific recurrent pattern of dna aberrations to be correlated with tumor histologic type or stage. However, CGH analysis could reveal new, recurrent genetic changes in gastric cancer affecting chromosomes sites that harbor genes known to participate in tumorigenesis and progression of several human malignant neoplasms.
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2/12. Complex cytogenetic abnormalities including telomeric associations and MEN1 mutation in a pediatric ependymoma.

    Ependymomas are neuroectodermal tumors of the brain and spinal cord. Some recurrent cytogenetic aberrations have been reported in these tumors, including alterations involving chromosomes 22, 6, and 11. However, consistent molecular alterations have not been identified in ependymal tumors. We studied a recurrent ependymoma in a 3-year-old patient by standard cytogenetic and molecular analysis of TP53 and MEN1 genes. In the present case, we found many of the cytogenetic features previously described as being recurrent in ependymomas, including unstable telomeric alterations. Furthermore, we detected a novel acquired heterozygous mutation in the MEN1 gene. The chromosomal instability produced by the telomeric alterations and the mutation in the MEN1 gene could be important events in the tumorigenesis of ependymomas.
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keywords = tumorigenesis
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3/12. Clonal development of a blastoid mantle cell lymphoma studied with comparative genomic hybridization.

    A molecular cytogenetic study was performed on the diagnostic tumor sample and three relapses from a case with blastoid mantle cell lymphoma. The clonal relatedness of the tumors was demonstrated by identical rearrangements of the immunoglobulin heavy chain gene and was supported by results from comparative genomic hybridization analyses. All samples shared the common alterations of losses of 6q, 9p, and 11q and gains of 3q, 9q, 12p, and 13q, suggesting that they were relatively early events in the tumorigenesis. Relapse 1 also showed a loss of 8p, while relapses 2 and 3 had gained the x chromosome and 7p, in addition, relapse 3 displayed gains of chromosomes 3 and 20. Taken together, the findings suggest that relapses 2 and 3 developed from the diagnostic tumor sample, while relapse 1 represents a separate lineage of tumor progression originating directly from a postulated ancestral tumor cell carrying the common chromosomal alterations identified in all tumors.
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keywords = tumorigenesis
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4/12. Analysis of chromosome abnormalities by comparative genomic hybridization in malignant peripheral primitive neuroectodermal tumor of the ovary.

    OBJECTIVE: Malignant primitive neuroectodermal tumor (PNET) originating from the ovary rather than from the central nervous system is extremely rare. The aim of this study is to demonstrate the chromosomal abnormalities in a case of peripheral primitive neuroectodermal tumor (PPNET) arising from the ovary of a girl. methods: The 13-year-old girl underwent exploratory laparotomy because of a huge pelvic tumor in lower abdomen and pelvis. She underwent removal of ovaries, tubes, omentum, peritoneal nodules, and portion of urinary bladder. Tumor specimens were sent for pathology, short-term tissue culture, and for storage in deep freezer for laboratory studies. Immunohistochemical stainings of the tumor with antibodies against O-13 (MIC/CD99), NSE, GFAP, S-100, cytokeratin AE1/AE3, desmin, NF, and AFP were performed. Short-term cell culture of fresh tumor was done for analysis of chromosomal aberrations by the technique of comparative genomic hybridization (CGH). names of specific genes corresponding to the losses or gains on gene map loci were identified from OMIM (Online Mendelian Inheritance in Man) of the NCBI website,. The overexpressions of N-myc and EGFR as well as underexpressions of Rb and ARHI were detected by RT-PCR analysis. The patient expired 17 months later despite of chemotherapy, repeated surgery, and radiation therapy. RESULT: The histopathology of the specimens revealed malignant neuroectodermal tumor, involving ovaries, tubes, bladder, omentum, and peritoneum. Immunohistochemical stainings of PPNET of the ovary showed positive reaction for O-13 (MIC2/CD99) and NSE, but negative for GFAP, S-100, cytokeratin AE1/AE3, desmin, NF, and AFP. Analysis of CGH revealed multiple chromosomal abnormalities including losses of chromosomes in 1p, 1q, 4q, 6p, 6q, 7q, 8q, 13q, and 19q; as well as gains of chromosomes in 1q, 2p, 7p, 9q, 18q, and Xq. Losses of 13q14.1-q14.2, 1p31, and 4q34-q35 indicated that Rb gene, ARHI, and FAT were deleted. Gains of 2p24.1, 1q23, and 7p12.3-p12.1 demonstrated that N-myc oncogene, FASL, GITRL, and EGFR were amplified. RT-PCR analysis showed that N-myc and EGFR were overexpressed, while Rb and ARHI were underexpressed. CONCLUSIONS: This report is the first to show multiple chromosomal aberrations in PPENT arising from the ovary. The deletions of Rb, ARHI, and FAT, as well as amplification of N-myc, FASL, GITRL, and EGFR, may be the crucial factors for tumorigenesis and the aggressive biological behavior of PPNET.
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keywords = tumorigenesis
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5/12. Fusion of the tumor-suppressor gene CHEK2 and the gene for the regulatory subunit B of protein phosphatase 2 PPP2R2A in childhood teratoma.

    We characterized the molecular genetic consequences of a balanced chromosome translocation t(8;22)(p21;q12), which occurred as the sole cytogenetic aberration in short-term cultured cells from an intrathoracic mature teratoma in a 15-year-old girl. fluorescence in situ hybridization and reverse transcription-polymerase chain reaction disclosed that t(8;22) resulted in the fusion of the genes PPP2R2A and CHEK2, with an inserted fragment belonging to class I endogenous retrovirus-related sequences at the junction. Sequencing of the two genes did not reveal any additional mutation. None of the three detected PPP2R2A/CHEK2 fusion transcripts resulted in an in-frame PPP2R2A/CHEK2 chimerical open reading frame; however, in all of them, the known open reading frame of CHEK2 was preserved. Thus, promoter swapping leading to deregulated CHEK2 expression would be the most likely oncogenic mechanism. Whereas inactivating mutations of CHEK2 previously have been described in a variety of sporadic tumors and in inherited cancer-predisposing syndromes, PPP2R2A, encoding a regulatory subunit of the multimeric enzyme phosphatase 2, has not been directly implicated in tumorigenesis. Our findings suggest that deregulation of CHEK2 and/or PPP2R2A is of pathogenetic importance in at least a subset of germ cell tumors.
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keywords = tumorigenesis
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6/12. Chromosome 13 alterations in osteosarcoma cell lines derived from a patient with previous retinoblastoma.

    Various sublines of cells established from an osteosarcoma that developed in a patient (O.H.) with previous bilateral retinoblastoma were examined for different restriction fragment-length polymorphisms of chromosome 13q, as well as for rearrangements of the retinoblastoma gene using a cDNA probe. The independently established sublines were used to help separate primary and secondary events taking place in tumorigenesis of the osteosarcoma of this patient. Information from the present dna analysis, taken together with data from cytogenetic and enzymatic studies on chromosome 13 in the cell lines, revealed both common and distinct genetic changes on chromosome 13q. The common changes may indicate the nature of the first and second mutational events in the development of the osteosarcoma. The first, constitutional cancer predisposing mutation seemed to be a base mutation or a small deletion/insertion, and the second event involved a deletion of a larger part of the long arm of chromosome 13. The distinct genetic changes included other deletion and duplication events of chromosome 13q. The existence of multiple sublines with different genetic constitutions provides improved possibilities for gaining insight into the nature of the genetic lesions leading to tumor formation, as these may reflect the clonal variation present in the primary tumor. We also demonstrate the difficulty of inferring from single tumor cell isolates to properties of the primary tumor.
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keywords = tumorigenesis
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7/12. Chromosomal evolution in the progression and metastasis of human malignant melanoma. A multiple lesion study.

    In order to distinguish those chromosomal aberrations associated with tumorigenesis from those associated with tumor progression of malignant melanoma, chromosome analysis was performed on eight tumors derived from one patient. Three common marker chromosomes, a deletion of chromosome 1, a deletion of chromosome 9, and a translocation involving chromosomes 7 and 12, were identified in each tumor. The presence of common markers in these intrapatient tumors indicates the monoclonal origin of these tumors. Furthermore, the consistent and specific involvement of chromosome 9 in both interpatient and intrapatient studies suggests the crucial role that chromosome 9 plays during the development of human malignant melanoma. In addition to common markers, different overlapping markers including those involving chromosomes 2, 3, and 6, were also identified, suggesting that chromosomes 2, 3, and 6 are most likely associated with the progression, instead of the genesis, of the tumor. Finally, lesion-specific marker chromosomes were identified in each tumor indicating the nonrandom selection and modification of the metastatic process. The nature of chromosomal evolution among the eight tumors was clearly demonstrated by the retention and amplification of specific marker chromosomes, with the latter tumors containing more overlapping markers than the early tumors and the recurrence of identical markers in the different branches of evolution. One of the last three tumors obtained immediately before the death of the patient contained all the overlapping markers identified in other tumors, which may indicate that a plateau of chromosomal evolution of these tumors has been reached. These observations demonstrate a nonrandom or programmed chromosome evolution of human neoplasia that could be intrinsic to the aneuploid nature of neoplasia.
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keywords = tumorigenesis
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8/12. Nephroblastomatosis and deletion of 11p. The potential etiologic relationship to subsequent Wilms' tumor.

    Both nephroblastomatosis and deletions of the short arm of chromosome 11 (11p-) have been associated independently with Wilms' tumor. The finding of 11p- in a specimen of nodular renal blastema in the currently described patient represents a previously unknown association with this chromosomal lesion. The possibility that 11p- produced an abnormal renal substrate (nephroblastomatosis), upon which the action of a second postzygotic genetic alteration led to Wilms' tumor, is considered. It is suggested that, in the present case, tumorigenesis may have been the result of two postzygotic events, one of which may have been postnatal. Recent cytogenetic observations in both Wilms' tumor and retinoblastoma support such an hypothesis.
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keywords = tumorigenesis
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9/12. The breakpoint of an inversion of chromosome 14 in a T-cell leukemia: sequences downstream of the immunoglobulin heavy chain locus are implicated in tumorigenesis.

    T-cell tumors are characterized by inversions or translocations of chromosome 14. The breakpoints of these karyotypic abnormalities occur in chromosome bands 14q11 and 14q32--the same bands in which the T-cell receptor (TCR) alpha-chain and immunoglobulin heavy chain genes have been mapped, respectively. patients with ataxia-telangiectasia are particularly prone to development of T-cell chronic lymphocytic leukemia with such chromosomal abnormalities. We now describe dna rearrangements of the TCR alpha-chain gene in an ataxia-telangiectasia-associated leukemia containing both a normal and an inverted chromosome 14. The normal chromosome 14 has undergone a productive join of TCR alpha-chain variable (V alpha) and joining (J alpha) gene segments. The other allele of the TCR alpha-chain gene features a dna rearrangement, about 50 kilobases from the TCR alpha-chain constant (C alpha) gene, that represents the breakpoint of the chromosome 14 inversion; this breakpoint is comprised of a TCR J alpha segment (from 14q11) fused to sequences derived from 14q32 but on the centromeric side of C mu. These results imply that 14q32 sequences located at an undetermined distance downstream of the immunoglobulin C mu locus can contribute to the development of T-cell tumors.
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keywords = tumorigenesis
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10/12. Duplication (20p) in association with thyroid carcinoma.

    We report on a girl with short stature, mental retardation, mutism, "coarse" facial appearance, and papillary-follicular thyroid carcinoma. She had dup(20p) derived from a paternal balanced translocation [(12p;20p)]. We speculate that the carcinoma in our patient may be related to the deletion of material from 12p resulting in absence of genetic material normally required for the suppression of thyroid tumorigenesis.
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keywords = tumorigenesis
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