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At least 487 records · Page 27Linked to original sources
PubMed2000

Cytogenetic survey of Holstein bulls at a commercial artificial insemination company to determine prevalence of bulls with centric fusion and chimeric anomalies.

OBJECTIVE: To determine prevalence of Holstein bulls with chromosomal anomalies, particularly the 1/21 centric fusion (CF), at a commercial artificial insemination (AI) company in the United States. DESIGN: Cross-sectional cytogenetic prevalence study. ANIMALS: All 606 Holstein bulls at a commercial AI company were cytogenetically screened to detect CF, chimerism, and other chromosomal abnormalities. PROCEDURE: Lymphocytes from heparinized blood samples were cultured by standard cytogenetic techniques, and chromosome spreads were prepared for microscopic examination. Chromosomal abnormalities were detected by examining 10 chromosome spreads per bull. Pedigree analysis was performed. RESULTS: None of the bulls had any type of CF. However, 6 bulls were identified as chimeras (i.e., contained lymphocytes with male [XY] and female [XX] chromosomes). One bull was sire or maternal grandsire to 85 of the bulls tested, and 739 of 1,212 (61%) sire and maternal-grandsire possibilities were accounted for by just 18 bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results supports previous indications that CF is extremely rare in Holstein bloodlines available commercially via AI in the United States. However, chimeric bulls are more common, and they reportedly have decreased reproductive performance. Therefore, identification of chimeric sires in the AI facility reported here and the possibility of de novo onset of CF at any time indicates that early cytogenetic screening should be encouraged for prospective bulls intended for use in AI programs.

Animals↗
PubMed1996

Cytogenetic evaluation of cystic hygroma associated with hydrops fetalis, oligohydramnios or intrauterine fetal death: the roles of amniocentesis, postmortem chorionic villus sampling and cystic hygroma paracentesis.

BACKGROUND: Pregnancies complicated by fetal cystic hygroma in the second and third trimesters are often associated with hydrops fetalis, oligohydramnios or intrauterine fetal death which may make genetic assessment more difficult. We investigated the roles of amniocentesis, postmortem chorionic villus sampling and cystic hygroma paracentesis in cytogenetic evaluation of cystic hygroma under such circumstances. METHODS: Thirty-five fetuses of cystic hygroma associated with hydrops fetalis, oligohydrammos, or intrauterine fetal death were studied. All fetuses were delivered at Mackay Memorial Hospital, Taipei, Taiwan between January, 1987 and July, 1995. Data collected included maternal age, prenatal sonograms, gestational age at diagnosis, fetal karyotypes and diagnostic procedures. RESULTS: Of 35 fetuses, all had hydrops fetalis, 19 had suffered IUFD at the time of diagnosis, and 10 had severe oligohydramnios. Cytogenetic studies were performed via amniocentesis, postmortem chorionic villus sampling, or cystic hygroma paracentesis. Successful karyotyping was achieved in 32 fetuses and the karyotype of 45,X was found in 24 fetuses. In cases with IUFD, successful karyotyping rates on cells from amniotic fluid, chorionic villi and cystic hygroma fluid were 88.9% (8 of 9), 69.2% (9 of 13) and 20% (1 of 5), respectively, whereas, in cases with living hydropic fetuses, successful karyotyping was achieved in 12 of 12 amniotic fluid and 5 of 5 cystic hygroma fluid samples. CONCLUSIONS: Amniocentesis is a better method for cytogenetic evaluation of fetal cystic hygroma associated with intrauterine fetal death than postmortem chorionic villus sampling and cystic hygroma paracentesis. However, in the case with a living hydropic fetus and oligohydramnios, cystic hygroma paracentesis appears to be a practical alternative for cytogenetic assessment.

Adult↗
PubMed2000

[Prenatal cytogenetic diagnosis at the Department of Medical Genetics GENNET-Klimentská].

OBJECTIVE: Analysis of data from prenatal cytogenetic studies performed during 10 years. DESIGN: Retrospective analysis of cytogenetic results. SETTING: Cytogenetic laboratory, Department of Clinical Genetics GENNET, Prague. METHODS: Cytogenetic analysis of cultivated amniotic cells. RESULTS: 180 chromosomal pathologies, including 110 numerical and 70 structural, were diagnosed in 5743 samples of amniotic fluid. Relatively high number of structural aberrations was found also in groups of patients examined because of increased maternal age, abnormal values of biochemical markers and abnormal ultrasound findings. Chromosomal abnormalities in individual groups of patients, risk figures for de novo balanced structural aberrations, additional marker chromosomes and some mosaic findings as the management following the prenatal diagnosis of this abnormalities are discussed. CONCLUSION: On the basis of the great number of familiar structural aberrations in our material is recommended to pay attention to the detection of such anomalies also in groups of patients where numerical chromosomal changes are namely expected.

Chromosome Aberrations↗
PubMed2001

Splenic marginal zone B-cell lymphomas: two cytogenetic subtypes, one with gain of 3q and the other with loss of 7q.

BACKGROUND AND OBJECTIVES: Splenic marginal zone B-cell lymphoma (SMZBCL) has clinical, immunophenotypic and histologic features distinct from other B-cell malignancies, but few chromosome studies have been previously reported. In the present study we performed conventional cytogenetics and in situ hybridization studies in 47 patients with SMZBCL. DESIGN AND METHODS: We studied 47 cases of splenic marginal zone B-cell lymphoma combining conventional cytogenetics and in situ hybridization (ISH) techniques using centromeric probes (chromosomes 3 and 12), locus specific probes (7q31 and 17p13) and cross-species color banding fluorescent ISH probes (RxFISH). The diagnosis of SMZBCL was ascertained in all cases after studying, morphologically and immunologically, peripheral blood and splenectomy specimens. RESULTS: A clonal chromosome abnormality detected by conventional cytogenetics and/or FISH was found in 33/47 patients (70%) being identified in 18 (18/33, 55%) as a complex abnormality. The most frequently recurrent abnormalities were: gain of 3q (10 cases), del(7q) (12 cases), and involvement of chromosomes 1, 8 and 14. No patient showed translocation t(11;14) (q13;q32) or t(14;18) (q21;q32). Trisomy 3 was detected in eight cases (8/47, 17%). Two novel cytogenetic abnormalities involving 14q32, t(6;14)(p12;q32) and t(10;14) (q24;q32) were reported. Deletion of 17p13 (P53) was observed by FISH in one case. Only one patient showed a gain of 3q or trisomy 3 and deletion 7q in the same karyotype. INTERPRETATION AND CONCLUSIONS: Our findings support the interpretation that two forms of SMZBCL could be considered, one with gain of 3q and the other with deletions at 7q.

Chromosome Aberrations↗
PubMed2001

Combined automatic immunological and molecular cytogenetic analysis allows exact identification and quantification of tumor cells in the bone marrow.

PURPOSE: To improve the detection of disseminated tumor cells in bone marrow (BM) and peripheral blood samples of solid tumor patients, a novel computer-assisted scanning system for automatic search, image analysis, and repositioning of these cells was developed. This system allows precise identification and quantification of tumor cells by sequential immunological and molecular cytogenetic analysis. In this study, we attempt to demonstrate the practical use of this approach by analyzing BM samples from neuroblastoma patients. EXPERIMENTAL DESIGN: The disialo-ganglioside (GD2) molecule was used as the immunological target. The GD2 molecule was described as being specific for neuroblastoma cells, although false positive reactions had been suspected. To verify or disprove the neoplastic nature of the immunologically positive cells, sequential fluorescence in situ hybridization was performed on these cells to search for those genetic aberrations found in the corresponding primary tumors. A total of 115 samples from 40 newly diagnosed patients were evaluated for the presence of GD2(+) cells in the BM. RESULTS: GD2 positivity was detected in 95.2% of stage 4 patients, in 100% of stage 4s patients, and in 38.5% of patients with localized/regional disease. In stage 4 and 4s BM samples, the GD2(+) cells were unequivocally identified as tumor cells based on the molecular cytogenetic aberrations found by fluorescence in situ hybridization. However, in BM samples from patients with localized/regional disease, all GD2(+) cells were concluded to represent false positivity due to the absence of genetic aberrations. CONCLUSIONS: Automatic search and sequential molecular cytogenetic analysis of the immunologically positive cells provide precise information on both the number and cytogenetic profile of disseminated tumor cells.

Bone Marrow Cells↗
PubMedDate not supplied

[Estimate of cytogenetic homeostasis in natural populations of some small murid rodents].

Cytogenetic homeostasis in natural populations under natural conditions and anthropogenic stress was estimated according to the frequency of chromosome aberrations in somatic cells for six species of small mammals. Cytogenetic homeostasis was disturbed under the stress effect of increased density during population cycles, at the ecological periphery, and in the case of environmental chemical and radiation contamination. Cytogenetic homeostasis disturbances were related to changes in other indices of homeostasis, such as developmental stability and immune status, suggesting the use of the cytogenetic approach for estimating the general state of individuals in natural populations.

Adaptation, Physiological↗
PubMed2002

[Molecular cytogenetic monitoring of chimerism and minimal residual disease in patient with chronic myeloid leukemia after allogenic and syngenic bone marrow transplantation].

AIM: To study trends in restoration of normal and tumor hemopoiesis after transplantation of allogenic and syngenic hemopoietic cells. MATERIAL AND METHODS: The examination of bone marrow before transplantation and 1, 2, 3, 6, 9 months, 1, 2 and 3 years after bone marrow transplantation (BMT) was made in 25 patients with chronic myeloid leukemia (CML) after allogenic transplantation of the bone marrow (TBM) and 4 patients after syngenic TBM. The method of G-differential staining of chromosomes and fluorescent hybridization in situ (FISH) with DNA probe to centromeric sites X/Y of chromosomes and genes BCR/ABL was used. RESULTS: 56% of CML patients after allogenic BMT were in cytogenetic and clinicohematological remission, 16% developed early cytogenetic recurrence. Single metaphase with t(9;22) were identified in 28%; 14.3% developed late cytogenetic and hematological recurrence. In patients in posttransplantation remission there were from 0.1 to 5.8% cells of the host. The number of cells of the host and the number of BCR/ABL-positive cells correlated significantly. CONCLUSION: The results of 8-year monitoring of chimerism and minimal residual disease validate application of molecular-cytogenetic methods for assessing transplant condition.

Adolescent↗
PubMed2002

[The morphological, immunophenotypical and cytogenetic characteristics study of blast crisis in chronic myeloid leukemia].

OBJECTIVE: To explore the morphological, immunophenotypical and cytogenetic (MIC) characteristics of chronic myeloid leukemia in blast crisis (CML-BC). METHODS: Marrow cells from 31 CML-BC patients were studied by bone marrow smears with morphological and cytochemical stain analysis. Immunophenotypic analysis was performed by micro blood method and flow cytometry. Cytogenetic analysis was performed using bone marrow cells prepared directly and or after 24 hours culture. RHG banding was used for karyotypic analysis. RESULTS: 23 patients (74.2%) were found to have myeloid blast crisis. 5 cases (16.1%) had a B-lymphoid immunophenotype and 4 of them expressed myeloid associated antigens at the same time. Another 3 cases were classified as acute undifferentiated leukemia (AUL 1 patient) and acute myeloid -lymphoid leukemia (AMLL 2 patients) with B and myeloid markers expression. A significant proportion (67.7%) of blast crisis cases were CD(34) positive. CD(34) was expressed in 80.0% of lymphoid and 65.2% of myeloid BC. Analysis of the relationship between CD(7) and CD(34) expression in blasts of myeloid crisis showed their dual expression in 8/23 (34.8%) of the cases. Cytogenetic analysis indicated that 14/27 (51.9%) of the patients had developed secondary cytogenetic abnormalities in addition to the Ph chromosome. These newly emerging abnormalities included a trisomy 8 in 3 patients, a double Ph chromosome in 3 patients, an iso chromosome 17q in 2 patients, loss of Y chromosome in 1 patent and other complicated translocation in 5 patients. CONCLUSION: Blast crisis of CML is a kind of disease of stem cell. The differentiation of blast cell is blocked in the early stage. The prognosis of such patients is poor. MIC showed its important values in diagnosis, judgement of prognosis and determination of therapeutic protocol of CML-BC.

Adult↗
PubMed2003

[Role of cytogenetics in the prognosis of patients with multiple myeloma].

The aim of the study was to evaluate the clinical and prognostic significance of cytogenetic abnormalities in multiple myeloma patients. Cytogenetic studies were performed in 95 myeloma patients aged 31-82 (median 64) prior to chemotherapy. The GTG and CBG chromosome banding were performed and chromosomal abnormalities were described according to International System for Human Cytogenetic Nomenclature ISCN (1995). An abnormal karyotype was observed in 29% myeloma patients. Patients with an abnormal karyotypes showed various numerical and structural aberrations with hyperdiploidy in 39%, hypodiploidy in 39% and pseudodiploidy in 18% of patients. Monosomy of chromosome 13 was present in 29% of patients with an abnormal karyotype. Multiple myeloma patients with chromosomal abnormalities had more advanced disease than those with normal karyotype (82% vs 57% had stage III myeloma). beta 2-microglobulin and LDH levels were higher and hemoglobin level was significantly lower in patients with an abnormal karyotype. The plasma cell involvement of bone marrow was significantly higher in these patients. Overall survival was significantly shorter of patients with abnormal karyotypes (median 24 months vs 18 months), particularly of patients with monosomy of chromosome 13 (median 14 months). Cytogenetic studies are helpful to evaluate the prognosis and treatment options in multiple myeloma patients.

Adult↗
PubMed2004

Cytogenetic and fluorescence in situ hybridization monitoring in Ph+ Chronic Myeloid Leukemia patients treated with imatinib mesylate.

Imatinib mesylate determines a favorable clinical course in most Ph positive Chronic Myeloid Leukemia (CML) patients in the chronic phase. Cytogenetic response is usually evaluated by analyzing 20-25 bone marrow metaphases using standard banding techniques. Since this methodology has very low sensitivity, we compared the results obtained by standard banding techniques to the ones obtained by fluorescent in situ hybridization (FISH). This was also done to identify any possible discrepancies between the two techniques. We analyzed 40 Ph+ CML patients in the chronic phase who had previously been treated with interferon alpha (IFNalpha) and who were receiving imatinib. The studies were performed by utilizing the same BM cell samples fixed in acetic acid/methanol, before imatinib therapy and then quarterly. Comparison of cytogenetic results to FISH results at 3 and 6 months of imatinib treatment showed that some patients who had achieved major cytogenetic response (i.e.<35% of examined metaphases showing Ph), showed retention of a higher number of persisting Ph+ cells when examined by FISH, and they did not achieve major FISH response (i.e. <35% of examined interphase cells show the BCR-ABL fusion signal). The discrepancy we found between the results that were obtained by analyzing metaphases and interphase cells disappeared in the subsequent examinations. Moreover, we found that 4 patients (10%) were still Ph+ in all the metaphases we examined even though they achieved excellent clinical response. On the basis of this small series of patients, we suggest that cytogenetic evaluation of patients on imatinib therapy should be performed by utilizing the classic banding technique (metaphase examination), but also by using the FISH technique (interphase examination), since the two methodologies may provide different results.

Adult↗
PubMed2005

The impact of the combination of baseline risk group and cytogenetic response on the survival of patients with chronic myeloid leukemia treated with interferon alpha.

BACKGROUND AND OBJECTIVES: This study was aimed at examining major cytogenetic response (MCR) as a valid predictor of the course of chronic myeloid leukemia (CML) and at assessing the survival of CML patients treated with interferon alpha (IFN) in dependence on the combination of MCR (yes or no) with the baseline risk group of the New CML score. MCR was defined as a reduction of Philadelphia chromosome-positive bone marrow cells to <or= 35%. The New CML score discriminated three risk groups with significantly different survival probabilities. DESIGN AND METHODS: Data from individual patients with a confirmed diagnosis of Philadelphia chromosome-positive CML treated with IFN were collected from 10 prospective studies in Europe and Japan. Stratified for baseline risk group, patients with a major cytogenetic response by 21 months after the start of therapy (n=171) were compared with patients achieving a minor response or less (n=487). Survival probabilities after the landmark at 21 months were compared by using the two-sided log-rank test. RESULTS: MCR was a major predictor for low- and intermediate-risk patients (log-rank test, p <or= 0.0001), but not for high-risk patients. Ten-year survival probabilities for the low- and intermediate-risk patients who had a MCR were 75% (95 CI: 65-86%) and 56% (95 CI: 37-75%), respectively. The corresponding probabilities for patients who did not achieve a MCR were 21% (95 CI: 6-35%) and 16% (95 CI: 6-25%). INTERPRETATION AND CONCLUSIONS: Cytogenetic response per se is not a valid surrogate marker, as it is dependent on the baseline prognostic profile. The combination of risk group and cytogenetic response does, however, provide useful clinical information. The survival data presented here can serve as a benchmark for the assessment of the long-term effectiveness of imatinib.

Adult↗
PubMedDate not supplied

[The significance of cytogenetic investigation for the estimation of Chernobyl accident consequences].

The results of the cytogenetic investigation of people, which were exposed to radiation in the result of the Chernobyl NPP accident, were presented. Also the possibilities of the application of cytogenetic findings for dose estimations and for the prediction of the radiation influence consequences were examined. During the period of time since 1986 till 2004 the cytogenetic investigations of 1724 liquidators participating in the liquidation works after the Chernobyl accident were carried out. The radiation dose estimated by the frequency of dicentrics in 1986 was about 0.16 Gy. The doses for liquidators were determined by the frequency of translocations (FISH method) during the period from 1992 till 1995. For liquidators who worked in Chernobyl only in 1986 the average dose of radiation was about 0.19 Gy and for liquidators who worked repeatedly during the period from 1986 till 1995 - 0.39 Gy. There was shown that during the whole period of investigation (1986-2004) the frequency of dicentrics in peripheral blood lymphocytes was significantly higher than the control level. The cytogenetic investigation of Bryansk region inhabitants which was carried out in 1992-1994 discovered heightened value in 5 times than the control one. Findings are of great importance for the prediction of ill effects of radiation and for the development of sensitive criterions for early exposure disturbances in state of health.

Case-Control Studies↗
PubMed2006

The outcome of molecular-cytogenetic subgroups in pediatric T-cell acute lymphoblastic leukemia: a retrospective study of patients treated according to DCOG or COALL protocols.

BACKGROUND AND OBJECTIVES: Subgroups of T-cell acute lymphoblastic leukemia (T-ALL), defined according to recurrent cytogenetic aberrations, may have different prognoses. The aim of this study was to determine the prognostic relevance of molecular-cytogenetic abnormalities in pediatric patients using quantitative real-time polymerase chain reaction and fluorescence in situ hybridization. DESIGN AND METHODS: The patients were assigned to TAL1, HOX11/TLX1, HOX11L2/TLX3, or CALM-AF10 subgroups. The cytogenetic subgroups were characterized in relation to immunophenotype and the expression of aberrantly expressed transcription factors. RESULTS: In our cohort study, CALM-AF10 was associated with an immature immunophenotype and poor outcome (p=0.005). HOX11L2 was associated with both immunophenotypically immature cases as well as cases committed to the gammadelta-lineage. HOX11L2 was significantly associated with poor outcome (p=0.01), independently of the expression of CD1 or the presence of NOTCH1 mutations. TAL1 abnormalities were associated with alphabeta-lineage commitment, and tended to be associated with a good outcome. Cells in HOX11 cases resembled early CD1-positive cortical thymocytes without expression of Cytbeta and TCR molecules. In relation to the expression of early T-cell transcription factors, high TAL1 levels were found in immunophenotypically-advanced cases, whereas high LYL1 levels were found in immature subgroups. INTERPRETATION AND CONCLUSIONS: The reported outcomes for HOX11L2-rearranged T-ALL cases are conflicting; the prognostic impact may depend on the therapy given. In our cohort, this cytogenetic aberration was associated with a poor outcome. Our data on CALM-AF10 rearranged T-ALL, albeit based on only three patients, suggest that this type of leukemia is associated with a poor outcome.

Adolescent↗
PubMed1988

Prognostic significance of additional cytogenetic abnormalities at diagnosis of Philadelphia chromosome-positive chronic granulocytic leukemia.

Of 661 patients with Philadelphia chromosome (Ph)-positive, nonblastic chronic granulocytic leukemia, 58 had cytogenetic abnormalities in addition to the Ph at the time of diagnosis. Twenty patients had reduplication of the Ph in one or more metaphases. Twenty-one patients with a single Ph exhibited hyperdiploidy in one or more metaphases. Eleven patients had two or more hypodiploid metaphases as their only numerical abnormality. The remaining six patients had a variety of abnormalities. Many patients had more than one type of abnormality. Survival of patients in the different subgroups was similar, but these 58 patients had a shorter course than the 603 patients without additional cytogenetic abnormalities (P less than .02). Survival curves for the two populations did not diverge until the 2-year point, after which the annual death rate among patients with additional cytogenetic abnormalities was approximately 40% higher than that of patients without such abnormalities. The two populations had similar relative risk values according to a hazard ratio formula previously described by the International CGL Prognosis Study Group. Thus, they would have been expected to have essentially identical survival curves. We conclude that the presence of additional cytogenetic abnormalities at the time of diagnosis constitutes an independently significant prognostic feature with an unusually delayed influence on survival.

Adolescent↗
PubMed1995

Interphase cytogenetic analysis of single cell suspensions prepared from previously formalin-fixed and paraffin-embedded tissues.

Fluorescence in situ hybridization (FISH) provides a rapid and accurate method for the detection of chromosomal aneuploidy. We have developed a technique for the use of FISH on single cell suspensions produced from either formalin-fixed or paraffin-embedded tissues. Preparation of such tissues involves sequential rehydration, enzymatic digestion to release single nuclei, and hybridization with a fluorescently labeled chromosome-specific centromeric probe. In a clinical setting formalin-fixed tissue from many tissue types is readily available for additional retrospective study. FISH on formalin-fixed tissues is especially beneficial in follow-up studies of cases involving termination after prenatal diagnosis or patients with a malignant disease where previous routine cytogenetics established the chromosomal aneuploidy. The use of this technique eliminates the biases of cytogenetic analysis due to clonal selection in tissue culture, the low number of cells analyzed, and the restriction to only dividing cell populations. We have demonstrated that this application of interphase cytogenetics to the study of various formalin-fixed tissues is amenable to the detection of chromosomal aneuploidies and has specific advantages over cytogenetic analysis.

Aneuploidy↗
PubMed1995

Evaluation of cytogenetic analysis for clinical preimplantation diagnosis.

OBJECTIVE: To evaluate the feasibility of using cytogenetic analysis in preimplantation diagnosis. DESIGN: Two different biopsy protocols (chemical drilling and zona cutting) and two fixation methods were tested in a mouse model. Afterwards, the efficiency of obtaining chromosome preparations from untransferable human embryos depending on the method used to obtain the blastomeres (embryos biopsy or removal of the zona pellucida and blastomere disaggregation) was determined. The chances of obtaining chromosome preparations depending on the type of embryo (haploid, diploid, triploid, and apparently unfertilized) were also evaluated. RESULTS: Results from the mouse model showed that chemical drilling yields better results than cutting in terms of metaphases per biopsied embryo and surviving rate after biopsy. In human embryos, biopsy of diploid embryos produced 46.6% chromosome preparations, while 29% were obtained after blastomere disaggregation and 20.4% when biopsying triploid embryos. CONCLUSIONS: These results suggest that the disaggregating procedure and triploid embryos cannot be considered as good models to assess the feasibility of cytogenetic analysis in preimplantation diagnosis. Poor chromosome quality and loss during fixation are the main problems to use cytogenetics in preimplantation diagnosis; a combination of cytogenetics and other techniques is suggested in cases of balanced translocations.

Animals↗
PubMed1995

Clinical and molecular cytogenetics and gene mapping: principles and techniques.

This article reviews the history of human cytogenetics with respect to technical advances from chromosome banding to molecular cytogenetics. Technologies such as in situ hybridization, chromosome painting, comparative genomic hybridization and interphase cytogenetics and their applications are discussed. The assignments of genes to chromosome regions by somatic cell genetics is illustrated by molecular analyses of somatic cell hybrid panels. The generation of complete physical maps of human chromosomes, by radiation hybrid mapping of sequence-tagged sites and establishment of chromosome-specific yeast artificial chromosome (YAC) banks and clone overlaps (contigs), is exemplified by studies of chromosome 18. The last section outlines the recent and future advances in clinical cytogenetics made possible by progress in molecular genetics.

Animals↗
PubMed1996

Fluorescence in situ hybridization (FISH) in cytogenetics of leukemia.

The principle of the fluorescence in situ hybridization (FISH) method is in the base pairing of the DNA probe to complementary sequences in the studied specimen. The hybridization of specific DNA or RNA probes to the cellular targets attached to the microscopic slides is widely used for the identification of chromosomal translocations, deletions, amplifications of specific genes, and chromosome number changes in mitotic and/or interphase cells. The use of FISH with the modifications of the basic method meant a breakthrough in detection and diagnosis of human malignancies. During the last tow years FISH was used in our laboratory for: (a) identification of constitutive and acquired numerical and structural chromosomal abnormalities; (b) detection of minimal residual disease or early relapse in patients treated for leukemia by bone marrow transplantation (BMT) and/or chemotherapy; (c) determination of the cytogenetic pattern of non-dividing or terminally differentiated cells. To confirm the structural rearrangements found by the classical G-banding technique, the whole chromosome painting probes which hybridize to multiple chromosomal sequences were used. The alpha-satellite DNA probes which detect centromeric repetitive sequences were utilized for determining the numerical and sex chromosome changes. Specific unique chromosomal sequences which can confirm all chromosomal rearrangements, i.e., deletions, translocations or inversions with the corresponding breakpoints were introduced for specific cases. Recently, every chromosomal translocation, deletion and any other structural or numerical change found by conventional cytogenetic analysis in the bone marrow cells of the patients with leukemia has been verified in our laboratory by FISH. The results of this study showed that FISH is more efficient than conventional cytogenetics in detecting residual malignant cells. For chromosomal rearrangements FISH is an extremely sensitive method which not only verifies but also interprets with more precision the findings of classical cytogenetics.

Chromosome Aberrations↗