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[Role of the processes of repair of DNA damage in the repair of cytogenetic disorders. Participation of the repair of DNA single-strand breaks in the repair of cytogenetic disorders].

A comparison was made between the results of the effect of poly(ADP-ribosylation) inhibitors (e.g. nicotinamide and 3-aminobenzamide) and a chromatin proteinase inhibitor, phenylmethylsulfonylfluoride, on the cytogenetic damages repair, by a micronucleus test and DNA repair in Chinese hamster fibroblasts. The values of the repair half-periods (5-7 min for the cytogenetic damages and 5 min for the rapidly repaired DNA damages) and a similar modifying effect with regard to radiation cytogenetic damages and kinetics of DNA damages repair were found to be close. This confirms the contribution of repair of DNA single-strand breaks in the initiation of structural damages to chromosomes.

Animals↗

Methodologies in cancer cytogenetics and molecular cytogenetics.

Various types of cytogenetic and molecular cytogenetic approaches, including conventional banding, fluorescence in situ hybridization (FISH), fiber-FISH, comparative genomic hybridization (CGH), matrix array CGH, chromosome microdissection, and microcell-mediated chromosome transfer are summarized. The rationale, advantage, and limitations of each approach are discussed with respect to research and clinical applications in human neoplasia.

Chromosome Banding↗

Cytogenetic abnormalities and clinical outcome in Wilms tumor: a study by the U.K. cancer cytogenetics group and the U.K. Children's Cancer Study Group.

BACKGROUND: Tumor genetic features reported to correlate with adverse outcome in Wilms tumor include karyotype complexity, losses of material from the short arm of chromosome 1 and from the long arms of chromosomes 11, 16 and 22 and gain of material from the long arm of chromosome 1. This study sought to test these associations in a large series of tumors studied by cytogenetic analysis. Identification of markers associated with elevated risk of relapse and fatal outcome could allow more effective treatment stratification at presentation. PROCEDURE: Thirteen member laboratories of the U.K. Cancer Cytogenetics Group provided results from a 12-year period. Karyotype abnormalities were correlated with clinical data (age, tumor stage, and histology) and outcome data provided by the central register of the U.K. Children's Cancer Study Group. RESULTS: Of 127 abnormal karyotypes, 78 included a reputedly "poor prognosis" feature. Univariate survival analysis showed no significant adverse effect for karyotype complexity, 1p loss or 11q loss. The poor outcome of cases with 16q loss was of borderline significance, but this effect was restricted to those tumors with unbalanced translocation der(16)t(1q;16q). The association between relapse risk and gain of 1q material was not significant. Only monosomy 22 was a significant marker of poor outcome in univariate analysis (13 cases showing 50% relapse free survival at 5 years compared to 79% survival for the remaining 114 cases, P = 0.02). In multivariate analysis, significant independent predictors of poor outcome were 1q gain (Hazard Ratio 3.4), stage IV disease (HR 5.0), and monosomy 22 (HR 5.9). CONCLUSIONS: Loss of chromosome 22 identifies high risk Wilms tumors. The prognostic significance of 1q gain, 16q loss and unbalanced translocation der(16)t(1q;16q) is unresolved and warrants further investigation.

Adolescent↗

Cytogenetics and molecular cytogenetics in prenatal diagnosis.

Prenatal chromosome diagnosis has been a rapidly changing field over the past 10 years for both sampling methodologies and molecular techniques to complement chromosome analysis. This review summarizes current techniques used by the clinician and their risks, and selected aspects of cytogenetic and molecular techniques used by the laboratories. Within the next 3 to 5 years, DNA techniques are expected to complement, and potentially replace, aspects of current cytogenetic and FISH techniques, and provide more detailed information on the genetic status of the fetus.

Adult↗

Cytogenetic and molecular-cytogenetic investigation of Rett syndrome: analysis of 31 cases.

Rett syndrome (RS) is a progressive encephalopathy restricted to the female sex. In the present study we investigated 30 females and one male with RS by cytogenetic and molecular-cytogenetic methods. We failed to identify any chromosomal rearrangements within the female groups and no correlation between fra(X)(p22) and RS in either the female group or the male. The boy with RS has karyotype 46,XY/47,XXY with abnormal cell clone (47,XXY) in 6-12% of his lymphocytes (revealed by fluorescence in situ hybridization analysis (FISH) of interphase cells with chromosome X-specific DNA probe). Our results indicated a possible connection between RS and X-chromosome replication disturbance. A late-replicating X-chromosome with a specific banding pattern (type 'C') has been observed in RS patients only. We propose to analyse the X-chromosome replication pattern as a test for confirmation of RS at preclinical diagnosis.

Adolescent↗

Interphase molecular cytogenetic screening for chromosomal abnormalities of prognostic significance in childhood acute lymphoblastic leukaemia: a UK Cancer Cytogenetics Group Study.

Summary Interphase fluorescence in situ hybridization (iFISH) was used independently to reveal chromosomal abnormalities of prognostic importance in a large, consecutive series of children (n = 2367) with acute lymphoblastic leukaemia (ALL). The fusions, TEL/AML1 and BCR/ABL, and rearrangements of the MLL gene occurred at frequencies of 22% (n = 447/2027) (25% in B-lineage ALL), 2% (n = 43/2027) and 2% (n = 47/2016) respectively. There was considerable variation in iFISH signal patterns both between and within patient samples. The TEL/AML1 probe showed the highest incidence of variation (59%, n = 524/884), which included 38 (2%) patients with clustered, multiple copies of AML1. We were thus able to define amplification of AML1 as a new recurrent abnormality in ALL, associated with a poor prognosis. Amplification involving the ABL gene, a rare recurrent abnormality confined to T ALL patients, was identified for the first time. The use of centromeric probes revealed significant hidden high hyperdiploidy of 33% and 59%, respectively, in patients with normal (n = 21/64) or failed (n = 32/54) cytogenetic results. The iFISH contributed significantly to the high success rate of 91% (n = 2114/2323) and the remarkable abnormality detection rate of 89% (n = 1879/2114). This study highlights the importance of iFISH as a complementary tool to cytogenetics in routine screening for significant chromosomal abnormalities in ALL.

Adolescent↗

Will the new cytogenetics replace the old cytogenetics?

With the advent of array-based comparative genomic hybridization technology, the analog cytogenetic analysis that has been used for the past 100 years could be replaced by the quantitative, microarray-based molecular analysis. Major advantages of the new array-based cytogenetic technologies are the high resolution and the high throughput. This technology is the first to offer an autonomous whole-chromosome analysis in one hybridization reaction for the detection of submicroscopic gains/losses. However, as with any new technology, it needs to be validated with regard to its performance in various applications (e.g. clinical genetic testing and cancer applications), comparative cost, and the data interpretation.

Chromosome Aberrations↗

Impact of cytogenetic and molecular cytogenetic studies on hematologic malignancies.

Conventional cytogenetic analysis of chromosome abnormalities in hematologic malignancies is hampered by the low mitotic index and poor quality of metaphases. A range of techniques based on fluorescence in situ hybridization (FISH) has greatly enhanced the identification of non-random translocations and deletions, pinpointing regions which contain genes involved in leukemogenesis. One of the main advantages of FISH is its ability to use non-dividing interphase cells as DNA targets, enabling the screening of large numbers of cells and providing access to a variety of cells with different hematopoetic activity. Furthermore, multicolor FISH (SKY, M-FISH and CGH microarrays) combines the screening potential of cytogenetics with the accuracy of molecular genetics, allowing the visualization of the entire human genome in 24 different colors.

Chromosome Aberrations↗

[Chromosomal in situ hybridization and interphase cytogenetics in single cell and tissue section preparations: new methods in tumor diagnosis and clinical cytogenetics].

To overcome the shortcomings encountered in classical cytogenetics, a variety of in situ hybridization techniques have been developed enabling metaphase and interphase cytogenetics on routinely processed tissues and cells. These techniques comprise the detection of numerical chromosome aberrations, the delineation or "painting" of whole chromosomes or certain chromosome regions and the visualization of structural chromosome rearrangements in interphase nuclei. Some of these new methods can reliably be applied also on paraffin-embedded tissues, among them the comparative genomic in situ hybridization (CGH) technique suitable for providing a survey of over- or underrepresented genetic material on the chromosomal level even if only tumour DNA is available.

Chromosome Aberrations↗

Quality aspects of prenatal cytogenetic diagnosis: determining the effect of various factors involved in handling amniotic fluid and chorionic villus material for cytogenetic diagnosis.

OBJECTIVES: To investigate the effect of factors involved in cell culturing and slide preparation of amniotic fluid (AF) and chorionic villus biopsies (CVB) for prenatal cytogenetic diagnosis. METHODS: The effect on the outcome of our standard AF cell culture procedure of volume and appearance of the submitted AF specimen, gynaecologist performing the amniocentesis, week of gestation in which the specimen was taken and culture medium was retrospectively investigated. In a prospective study controlled experimental variation was introduced in composition of fixative, relative humidity, temperature and airflow during slide preparation from primary CVB and AF in situ cultures. For evaluation, analysis of regression or variance was used. RESULTS: Provided that at least 0.8 mL AF per culture dish was admitted, none of the investigated factors appeared as critical resulting in unacceptable variation in outcome. Variation in appearance of the AF had a relatively major impact: bloody or brown AF resulted in a 3 days longer culture time. To a limited degree, metaphase quality of AF and CVB cells was affected by composition of fixative, relative humidity, ambient temperature and airflow during slide preparation. CONCLUSION: Current prenatal cytogenetic practice as described here appears in general to be robust and reliable. The investigated conditions are not critical within the investigated range. Expensive measures for fine control of these conditions are, therefore, not required.

Amniotic Fluid↗

Cytogenetics in multiple myeloma and plasma cell leukemia: simultaneous cytogenetic and cytologic studies in 51 patients.

Cytogenetic studies in patients with multiple myeloma (MM) and plasma cell leukemia (PCL) have in general been largely unsuccessful. The investigation of mitoses of nonmalignant hematopoietic precursor cells, rather than mitoses of malignant plasma cells might account for the low percentage of pathological genetic findings. We investigated bone marrow (BM) cells of 51 patients both cytogenetically and cytologically. In patients with a normal karyotype (n = 39) nearly all mitoses examined cytologically (107/117) derived from granulopoietic or erythropoietic cell lineages. In contrast, 20/27 metaphases in patients with a pathological karyotype (n = 12) were found to be plasma cell mitoses. These findings may explain the low rate of chromosomal rearrangements in MM and may suggest that the real abnormality rate is considerably higher.

Bone Marrow↗

Uterine leiomyoma cytogenetics. III. Interphase cytogenetic analysis of karyotypically normal uterine leiomyoma excludes possibility of undetected trisomy 12.

Uterine leiomyoma, a benign tumor that histopathologically is rather homogeneous, was recently characterized cytogenetically. About 40% of the investigated tumors are associated with clonal chromosome abnormalities and five different subgroups have been identified, characterized by trisomy 12, t(12;14)(q14-15;q23-24), del(7q), t(1;2)(p36;p24), and 6p rearrangements. In our survey of 76 cases, trisomy 12 was observed in 10% of the abnormal cases. To exclude a possible underscoring of this abnormality, we reexamined 15 of the cases with normal karyotype by interphase cytogenetics using a chromosome 12 alphoid DNA probe.

Chromosomes, Human, Pair 12↗

Cytogenetic and molecular cytogenetic analyses in diffuse astrocytomas.

Diffuse astrocytomas are highly variable tumors and show complex biologic behavior that is based on multi-step oncogenesis. We report cytogenetic and molecular cytogenetic investigations in 23 cases of diffuse astrocytomas. The results of conventional karyotyping, interphase fluorescence in situ hybridization (FISH), comparative genomic hybridization, multicolor FISH, and spectral karyotyping are reported. Various numerical and structural chromosomal aberrations were identified. Clustering of structural alterations in the short arm of chromosome 2 (2p) and the long arm of chromosome 7 (7q) were detected. Using spectral karyotyping, additional chromosome rearrangements not detectable by conventional methods were found. Some of these anomalies have not been previously described in diffuse astrocytomas. An independent validation of these discrepant findings is required.

Aneuploidy↗

Cytogenetic and molecular cytogenetic studies of a variant of t(21;22), ins(22;21)(q12;q21q22), with a deletion of the 3' EWSR1 gene in a patient with Ewing sarcoma.

Ewing sarcoma is the second most common malignant bone tumor in children and young adults. Cytogenetic analysis to identify a common t(11;22)(q23;q12) or less frequently a t(21;22)(q22;q12) or t(7;22)(p22;q12) plays an important role in the confirmation of the clinical diagnosis. We report a case of a 10-year-old female who had extraskeletal Ewing sarcoma. Conventional cytogenetic analysis revealed that 11 out of 20 cells had a derivative chromosome 22, possibly due to an insertion of the long arm of the 21q21 approximately q22. This finding was confirmed by fluorescence in situ hybridization (FISH) utilizing whole chromosome paint probes specific for chromosomes 21 and 22. Hybridization utilizing LSI EWSR1, dual-color break-apart rearrangement probe unexpectedly revealed that the 3' EWSR1 gene was lost on the derivative chromosome 22. This finding suggests that the insertion of chromosome 21 is another mechanism that could lead to EWS-ERG gene fusion. To our knowledge, this is the first case report of an insertion of a segment of 21q21 approximately q22 into the long arm of 21q12 with a loss of a DNA segment around the breakpoint on the derivative chromosome 22 in Ewing sarcoma.

Calmodulin-Binding Proteins↗

No cytogenetic evidence for involvement of gene(s) at 2p16 in sporadic cardiac myxomas: cytogenetic changes in ten sporadic cardiac myxomas.

Cardiac myxomas are significant causes of cardiovascular morbidity and mortality. Their genetic background is presently unknown. Recently, linkage analysis in cardiac myxomas of Carney complex patients has indicated that 2p16 and 17q2 might carry genes responsible for the development of hereditary cardiac myxomas. Less is known about sporadic cardiac myxomas. To date, cytogenetic analysis has been performed on 13 sporadic cases, and no specific rearrangement has been deduced. We studied 15 sporadic cardiac myxomas and reviewed the literature. Ten of the present cases revealed abnormal karyotypes with clonal and nonclonal rearrangements including dicentric chromosomes and telomeric associations. No cytogenetic evidence was found for a role of 2p16 in the development of sporadic cases. Region 17q2 was involved in structural rearrangements, but to a lesser extent than other regions. Structural rearrangements involving regions 12p1 and 17p1 are more frequently present and might therefore harbor genes important for the development of sporadic cardiac myxomas.

Adult↗

Complex karyotypes in childhood acute lymphoblastic leukemia: cytogenetic and molecular cytogenetic study of 21 cases.

Cytogenetic and molecular cytogenetic analysis of 79 childhood acute lymphoblastic leukemias (ALL) revealed chromosomal abnormalities in 76 (96%). Complex karyotypes (a finding of three and more chromosomal aberrations in a karyotype) were identified in 21 (26.6%) out of 79 patients. In 11 patients, complex karyotypes have included common recurrent chromosomal abnormalities, such as translocation t(12;21) in seven cases, t(9;22) in two cases, one case with t(2;1;19) and another one with translocation involving 11q23. In 10 patients, miscellaneous abnormalities were detected. Five patients displayed hyperdiploidy (47 approximately 57 chromosomes), three patients complex karyotypes with deletions of 9p, one patient with two new complex translocations t(2;4;12;13) and t(7;11;20), and the last patient with dic(12;21). The evaluation of the frequency of the chromosomal breaks (>5 per chromosome) showed that chromosomes 2, 4, 5, 7, 9, 12, 13, and 21 were most frequently affected. Survival analysis revealed statistically significant unfavorable event-free survival (EFS) (P=0.013) and decreased overall survival in the group with complex karyotypes (n=21) compared with the other cases (n=58). The evaluation of overexpression profile revealed increased occurrence of double CD13/CD33 positivity in patients with common recurrent chromosomal abnormalities (in 70% of cases); no such cases were registered in the other group (P<0.01).

Antigens, CD↗

Cytogenetic investigations of 340 thyroid hyperplasias and adenomas revealing correlations between cytogenetic findings and histology.

Cytogenetic analyses were performed on 340 follicular thyroid adenomas and goiters after short-term culture. Clonal chromosomal changes were found in 67 cases. Trisomy 7 as the sole abnormality or along with other trisomies was the most frequent type of aberration (19 cases). Other recurrent numerical changes were loss of chromosome 22 (4 cases) and the second X or the Y chromosome (5 cases). Translocations involving 19q13 (12 cases) were frequent structural chromosomal changes. Dicentric chromosomes or telomeric associations were frequent in goiters (12 cases). After a histopathologic classification of all cases, we have correlated the cytogenetic findings with the histology of the tumors. Only 8.4% of the goiters showed clonal abnormalities, whereas 44.9% of the adenomas revealed clonal abnormalities. Furthermore, simple clonal changes were predominantly found in goiters and complex changes in adenomas. The most impressive correlation was found in the group of lesions with trisomy 7. Although all but one lesion with one or two additional trisomies were goiters, those having three or more additional trisomies were all adenomas or adenomatous goiters.

Adenoma↗

Cytogenetic analysis of hepatoblastoma: hypothesis of cytogenetic evolution in such tumors and results of a multicentric study.

Hepatoblastoma is a rare pediatric malignant tumor of the liver. Previous cytogenetic reports are sporadic. We karyotyped nine consecutive hepatoblastomas from the Italian centers participating in a multicentric study on hepatic tumors (SIOPEL 1). Six cases showed abnormal karyotypes. The most common abnormalities were trisomies of chromosomes 2 and 20. Four cases showed abnormalities of chromosome 1. On the basis of findings, we speculate the possibility of a cytogenetic evolutive pattern of hepatoblastomas.

Child, Preschool↗