Biomedical subjects

S Knuutila

Publications and source records attributed to S Knuutila.

At least 109 records · Page 6Linked to original sources

PubMed1998

DNA copy number changes in development and progression in leiomyosarcomas of soft tissues.

DNA copy number changes were investigated in 29 leiomyosarcomas by comparative genomic hybridization. The most frequent losses were detected in 10q (20 cases, 69%) and 13q (17 cases, 59%). The most frequent gains were detected in 17p (16 cases, 55%). The most frequent high-level amplifications were detected in 17p (7 cases, 24%) and 8q (6 cases, 21%). A total of 137 losses and 204 gains were detected. Small tumors (less than 5 cm in diameter) displayed fewer changes per sample (3 to 11; mean, 7) than the other tumors (4 to 22; mean, 13). There was an increase in the number of gains from small tumors (mean, 4) to very large tumors (>20 cm; mean, 10). However, the number of losses was similar in small, large, and very large tumors (mean, 4.5). Tumor size-related aberrations were observed. Gains in 16p were detected in all small tumors but were infrequent in large and very large tumors (27% and 11%, respectively). Similarly, gains and high-level amplifications in 17p were more common in small (80%) than in very large tumors (33%). Gains in 1q, 5p, 6q, and 8q were not seen in any of the small tumors but were detected in large and very large tumors. Gains in 6q and 8q occurred in 8 of 9 cases (89%) of very large tumors, 5 of them with a high-level amplification in 8q.

Adult↗

PubMed1998

Different patterns of DNA copy number changes in gastrointestinal stromal tumors, leiomyomas, and schwannomas.

It is not uniformly agreed whether gastrointestinal stromal tumors (GISTs) are phenotypical variants of leiomyomas (cellular leiomyomas) or whether they represent a separate, genotypically definable entity. In an attempt to solve this question, we examined immunohistochemically defined leiomyomas from the esophagus and uterus, gastric schwannomas, and benign gastrointestinal stromal tumors (GIST) by comparative genomic hybridization (CGH). All 14 leiomyomas (nine esophageal, five uterine) were actin- and desmin-positive but negative for CD34 and S100-protein. Changes in DNA copy numbers were seen only in three esophageal leiomyomas. Gains were observed in chromosomes 3, 4, 5, 8, and 17, whereas losses were seen in 16p. All schwannomas were positive for S100-protein and negative for actin, desmin, and CD34. In schwannomas, the only change by CGH was a gain in 11q in one case. The benign GISTs, all from the stomach, were positive for CD34 but negative for desmin and S100-protein; two cases were positive for actin. The CGH findings in the GISTs differed markedly from those in leiomyomas and schwannomas. Ten of the 13 cases (77%) showed DNA copy number losses in 14q, and additional or other losses were found in eight cases, most often in chromosome 22 (seven cases), 15 (three cases), and 1p (two cases). Furthermore, two of the GISTs showed gains in 5q. These results indicate that phenotypically undifferentiated GISTs are also genetically different from leiomyomas and schwannomas and support their classification apart from leiomyomas.

Actins↗

PubMed1998

Presence of high-level DNA copy number gains in gastric carcinoma and severely dysplastic adenomas but not in moderately dysplastic adenomas.

Our aim was to investigate the presence of DNA copy number changes in gastric adenomas and to identify the changes that may play a role in gastric carcinogenesis. DNA copy number changes in 16 patients with gastric adenoma and in 22 tumors from patients with intestinal type gastric carcinomas were studied by using comparative genomic hybridization. DNA copy number changes were found in 44% of the adenoma cases and in 86% of the intestinal type gastric carcinomas. On average, gains were more common than losses (0.9 vs. 0.5 in adenomas and 4.1 vs. 1.8 in carcinomas). In adenomas, the most common gains involved chromosome 8 in 3 cases, and gain of chromosome 7 and 20q was detected in 2 cases. The most frequent losses were observed at 5q (three times). Only adenomas with severe dysplasia showed high-level amplifications that were detected at chromosome 13, 17cen-q22, and 20q12-ter. In gastric cancer, the most common gains were detected at 20q (55%), 17q12-q21 (41%), and 8q (41%), and the most common losses were detected at 18q (41%) and 4q (32%). High-level amplifications were observed at 20q (3 tumors), 17cen-q21 (3 tumors), 2p (1 tumor), and 18q (1 tumor). These findings suggest that the progression of dysplasia is associated with higher levels of DNA copy number increase (e.g., the gains at 17q and 20q), which were typically observed in the intestinal type gastric cancer. Furthermore, the results support the hypothesis that adenoma precedes cancer.

Adenocarcinoma↗

PubMed1998

Comparison of DNA copy number changes in malignant mesothelioma, adenocarcinoma and large-cell anaplastic carcinoma of the lung.

The differential diagnosis of mesothelioma, primary adenocarcinomas and pleural metastases frequently causes problems. We have used the comparative genomic hybridization (CGH) technique on 34 malignant mesotheliomas and 30 primary lung carcinomas (adenocarcinoma, including bronchoalveolar carcinoma and large-cell anaplastic carcinoma) to compare their copy number changes and to evaluate the use of CGH to distinguish between these two types of tumour. In mesothelioma, gains of genetic material occurred as frequently as losses, whereas gains predominated over losses in carcinoma. In mesothelioma, the most frequent changes were losses in 4q, 6q and 14q and gains in 15q and 7p, whereas gains in 8q, 1q, 7p, 5p and 6p were the most common changes in carcinoma. Amplification of KRAS2 was detected in two adenocarcinomas by Southern blot analysis. CGH showed gains in 12p in the same tumours. Statistically significant differences between the two types of tumour were detected in chromosomes X, 1, 2p, 4, 8q, 10q, 12p, 14q, 15q and 18q. When comparing the frequency of gains and losses between mesothelioma and lung carcinoma using discriminant analysis, the sensitivity of CGH to differentiate mesotheliomas from lung carcinomas was 81% and the specificity 77%. The differences in DNA copy number changes between the two types of tumour suggest that they are genetically different tumour entities. Although CGH cannot be used as a definitive discriminatory method, we were able to distinguish between mesothelioma and lung carcinoma in a large proportion of the abnormal cases.

Adenocarcinoma↗

PubMed1998

Comparison of benign and malignant follicular thyroid tumours by comparative genomic hybridization.

DNA copy number changes were compared in 29 histologically benign follicular adenomas, of which five were atypical, and 13 follicular carcinomas of the thyroid by comparative genomic hybridization. DNA copy number changes were frequent in adenomas (14 out of 29, 48%). Most changes were gains, and they always involved a gain of the entire chromosome 7 (10 out of 29, 34%); other common gains involved chromosomes 5 (28%), 9 (10%), 12 (24%), 14 (21%), 17 (17%), 18 (14%) and X (17%). Losses were found only in four (14%) adenomas. Two of the five atypical adenomas had DNA copy number losses, and none had gains. Unlike adenomas, gains were rare and losses were frequent in carcinomas. A loss of chromosome 22 or 22q was particularly common in carcinomas (6 out of 13, 46%), whereas a loss of chromosome 22 was found in only two (7%) adenomas, one of which was atypical (P = 0.002). A loss of 1p was also frequent in carcinomas (31%), but gains of chromosomes 5, 7, 12, 14 or X that were common in adenomas were not found. Loss of chromosome 22 or 22q was present in six of the eight widely invasive follicular carcinomas, but in only one of the five minimally invasive carcinomas. We conclude that large DNA copy number changes are common in thyroid adenomas. These changes are strikingly different from those found in follicular carcinomas consisting of few losses and frequent gains, especially those of chromosome 7. A loss of chromosome 22 is common in widely invasive follicular carcinoma.

Adenoma↗

PubMed1998

Comparative genomic hybridization in childhood acute lymphoblastic leukemia.

DNA copy number changes were studied by comparative genomic hybridization (CGH) on bone marrow samples obtained from 72 patients with childhood acute lymphoblastic leukemia (ALL) at diagnosis. The patients had been admitted to the Helsinki University Central Hospital (Finland) between 1982 and 1997. CGH showed DNA copy number changes in 45 patients (62.5%) with a mean of 4.6 aberrations per patient (range, 1 to 22). The results of CGH and chromosome banding analysis were generally concordant, but CGH facilitated specific karyotyping in 34 cases. DNA copy number gains were more frequent than losses (gains:losses, 6:1). Gains of DNA sequences affected almost exclusively whole chromosomes and were most commonly observed in chromosomes 21 (25%), 18 (22.2%), X (19.4%), 10 (19.4%) and 17 (19.4%). The most common partial gain was 1q31-q32 (8.3%). The most common gains of chromosomes 21, 18, X, 10, 17, 14, 4, 6 and 8 appeared concurrently. High-level amplifications of small chromosome regions were sporadic, detected only in two patients (2.8%). Chromosome 21 was involved in both cases. The most common losses were 9p22-pter (12.5%) and 12p13-pter (11.1%). No statistically significant association between the CGH findings and the diagnostic white blood cell count was observed.

Adolescent↗

PubMed1998

Optimized mitogen stimulation induces proliferation of neoplastic B cells in chronic lymphocytic leukemia: significance for cytogenetic analysis.The Tampere Chronic Lympocytic Leukemia group.

We tested the effects of interleukin-2 (IL-2), human recombinant tumor necrosis factor alpha (TNF-alpha), Staphylococcus aureus Cowan I (SAC), TPA, and their combinations, using a standard thymidine incorporation assay, in order to identify an optimal mitogen combination (OMC) for 24 consecutive patients with B-cell chronic lymphocytic leukemia (B-CLL). The combination that induced the highest thymidine incorporation was chosen as the OMC for each patient. Among 14 mitogen combinations tested, there were six different OMCs, of which the most frequent was TNF-alpha + IL-2. It was the OMC in 9 of 24 cases. The other OMCs were TNF-alpha + TPA1 (5/24), SAC + IL-2 (5/24), TPA1 + IL-2 (3/24), TPA10 + IL-2 (1/24), and TNF-alpha + TPA10 + IL-1 (1/24). The mitogenic power of the selected OMC in each case was then evaluated both by the combination of immunophenotyping and molecular cytogenetic techniques known as MAC (Morphology, Antibody, Chromosomes) and standard chromosome analysis. After OMC stimulation, the levels of DNA synthesis and B-cell proliferation (mitotic index) were, on average, 10-fold higher than those observed after standard TPA stimulation (P < 0. 0001). The proportion of mitotic B cells exceeded the proportion of mitotic T cells in 70.1% of the cases after OMC stimulation. After TPA stimulation, 7.7% +/- 2.5% of all mitoses were B-cell mitoses, whereas after OMC stimulation this proportion rose to 57.9% +/- 5.3%. The frequency of clonal chromosomal aberrations increased from 46% after TPA stimulation to 79% after OMC stimulation. The clonal aberrations del(6q), del(11q), and/or del(13q) were observed in 26%, 32%, and 42% of the patients with the respective clonal chromosomal aberrations, whereas the corresponding frequencies after TPA stimulation were only 4%, 21%, and 17%. When the lineage involvement of cells with clonal chromosomal aberrations from three patients was analyzed, the aberrations were found to be restricted to B cells only, and in one patient to a minor subset of B cells. The results demonstrate that an individually chosen OMC induces a high rate of proliferation in neoplastic B cells. We found deletions in 6q, 11q, and 13q at higher frequencies than reported previously, most probably as a result of an improved mitogenic response. The identification of an optimal mitogen stimulation for each patient, prior to chromosome analysis, can well be expected to reduce the rate of false-normal results in the future. This is essential for accurate evaluation of the prognostic significance of chromosomal aberrations in B-CLL.

Aged↗

PubMed1998

DNA copy number changes in alveolar soft part sarcoma: a comparative genomic hybridization study.

Alveolar soft part sarcoma (ASPS) is a rare, histologically distinctive soft tissue sarcoma typically occurring in children and young adults. Although the tumor often shows focal expression of muscle markers, its relationship with rhabdomyosarcoma is not established. The genetic background of ASPS is poorly understood. This study was undertaken to analyze the DNA copy number changes in 13 cases of ASPS using comparative genomic hybridization (CGH) on formaldehyde-fixed, paraffin-embedded tissue sections. Four ASPS cases showed DNA copy number changes. Gains were more common than losses. Gains observed in more than one case included 1q, 8q, 12q and 16p. Although these findings do not show consistent DNA copy number changes in ASPS, they give preliminary clues to genomic areas that might be important in the pathogenesis of ASPS.

Adolescent↗

PubMed1998

DNA copy number amplifications in human neoplasms: review of comparative genomic hybridization studies.

This review summarizes reports of recurrent DNA sequence copy number amplifications in human neoplasms detected by comparative genomic hybridization. Some of the chromosomal areas with recurrent DNA copy number amplifications (amplicons) of 1p22-p31, 1p32-p36, 1q, 2p13-p16, 2p23-p25, 2q31-q33, 3q, 5p, 6p12-pter, 7p12-p13, 7q11.2, 7q21-q22, 8p11-p12, 8q, 11q13-q14, 12p, 12q13-q21, 13q14, 13q22-qter, 14q13-q21, 15q24-qter, 17p11.2-p12, 17q12-q21, 17q22-qter, 18q, 19p13.2-pter, 19cen-q13.3, 20p11.2-p12, 20q, Xp11.2-p21, and Xp11-q13 and genes therein are presented in more detail. The paper with more than 150 references and two tables can be accessed from our web site http://www.helsinki.fi/lglvwww/CMG.html. The data will be updated biannually until the year 2001.

Chromosome Aberrations↗

PubMed1998

DNA gains in 3q occur frequently in squamous cell carcinoma of the lung, but not in adenocarcinoma.

We performed a comparative genomic hybridization study on 25 samples of adenocarcinoma and 19 samples of squamous cell carcinoma of the lung to detect recurrent changes in the genetic material. DNA copy number changes were found in 16 squamous cell carcinoma samples and 17 adenocarcinoma samples. The most common changes were gains of DNA sequences in 3q (43%), 1q (34%), 8q (32%), 5p, (30%), 7p (25%), and 12p (25%). Of the squamous cell carcinoma samples with DNA copy number changes, 94% (15/16) had a gain in 3q (minimal common region of overlap q24-qter), whereas only 24% (4/17) of the adenocarcinoma samples with DNA copy number changes showed a gain in 3q (q22-qter) (P < 0.001). Six high-level amplifications in 3q (q26.2-q26.3) were detected in the squamous cell carcinoma samples but none were observed in the adenocarcinoma samples. Our results suggest that amplification of genes in 3q may be important in the tumorigenesis of squamous cell carcinoma but not necessarily of adenocarcinoma.

Adenocarcinoma↗

PubMed1998

Comparative genomic hybridization of low-grade central osteosarcoma.

Very little is known concerning the cytogenetic and molecular genetic changes of low-grade central osteosarcoma, a rare form of osteosarcoma. In the present study, we used comparative genomic hybridization (CGH) to screen for DNA sequence copy number aberrations in 10 samples from 6 patients: 7 typical low-grade central osteosarcomas, one low-grade (Grade II) central osteosarcoma, and two high-grade (III and IV) local recurrences of a low-grade central osteosarcoma Nine samples had aberrations. Six typical low-grade central osteosarcoma samples had a single DNA sequence copy number change per tumor. Three samples from more advanced tumors (a Grade II low-grade central osteosarcoma and local recurrences of Grade III and IV) had a mean of five changes per tumor. Recurrent changes affected these minimal common regions: +12q13-q14 (three tumors), +12p (two tumors), and +6p21.1-p21.3 (two tumors). Nine samples were analyzed for CDK4 and MDM2 expression and SAS amplification. One sample with a gain of chromosome 12 had a very strong expression of MDM2, strong expression of CDK4, and amplification of SAS. One sample with a gain of 12q13-q14 had strong expression of CDK4 and MDM2. Strong expression of CDK4 was found in two additional tumors; one had a gain of 12q13-q21, and the other had no changes in chromosome 12 by CGH. No alterations were detected in the CDK4, MDM2, and SAS panel in three other samples with no changes in chromosome 12 by CGH. In conclusion, the low number of DNA sequence copy number alterations reflects the relatively low malignancy of low-grade central osteosarcoma. This simplicity differs from the complex aberrations seen in conventional high-grade osteosarcomas.

Adolescent↗

PubMed1998

Genetic imbalances in 67 synovial sarcomas evaluated by comparative genomic hybridization.

We used comparative genomic hybridization (CGH) to evaluate DNA sequence copy number changes in 67 synovial sarcomas of both monophasic and biphasic histological subtypes. Changes (mean among aberrant cases: 4.7 aberrations/tumor; range: 1-17), affecting most often entire chromosomes or chromosome arms, were detected in 37 sarcomas (55%). Gains and losses were distributed equally, but different chromosomes were affected with variable frequencies. The most frequent aberrations, each detected in 9-11 of 67 tumors, were gain of 8q and gain at 12q (12q14-15 and 12q23-qter), loss of 13q21-31, and loss of 3p. Other frequent changes (in 7 or 8 cases) included gains at 2p, 1q24-31, and 17q22-qter, and losses at 3cen-q23 and 10q21. High-level amplifications were seen in 7 cases. A total of 16 regions were detected. Two of them, 8p12-qter and 21q21-qter, seen in 4 and 2 tumors, respectively, were recurrent. No aberrations specific to histological subtype were identified. However, genetic changes in the monophasic tumors were more complex and numerous (mean among aberrant cases: 5.3 aberrations/tumor; range: 1-17) than in the biphasic tumors (mean: 2.5 aberrations/tumor; range: 1-5), and high-level amplifications occurred more frequently. All but 1 of the sarcomas showing high-level amplification were of the monophasic subtype. These findings may reflect differences in the pathogenesis and biological behavior of both histological subtypes of synovial sarcoma.

Adolescent↗

PubMed1998

Low number of DNA copy number changes in small lymphocytic lymphoma.

BACKGROUND AND OBJECTIVE: Small lymphocytic lymphoma (SLL) is morphologically and immunologically similar to chronic lymphocytic leukemia (CLL), and the new REAL classification refers to them as a single disease termed SLL/CLL. Recently, frequent losses in 6q, 11q and/or 13q were observed in CLL using comparative genomic hybridization (CGH). We performed CGH analyses in order to find out whether these two entities contain the same DNA copy number changes. DESIGN AND METHODS: Seventeen patients with stage IV disease and one with stage III disease were studied by CGH. CGH is based on quantitation of the fluorescence intensity of differentially labeled DNAs. For this purpose tumor DNA labeled with FITC-12dUTP and normal DNA labeled with Texas red-5dUTP were hybridized to normal metaphase chromosomes. The ratio of fluorescence intensity of hybridized tumor and normal DNA was measured using computerized image microscopy to identify over- or under-represented regions in the tumor genome. All findings were confirmed using a confidence interval of 99% with a 1% error probability. RESULTS: The most consistent finding was a gain of the entire chromosome 12 observed in three patients and a loss in 14q24 in one patient. No other changes were detected. All abnormal cases presented with stage IV disease and had bone marrow infiltration. Two 12+ cases had a leukemic disease. INTERPRETATION AND CONCLUSIONS: Our results indicate that trisomy 12 is one of the most frequent chromosomal aberrations in SLL. Losses regarded as typical of CLL were not present in SLL. This may indicate that the genetic pathways in the development of SLL/CLL in patients presenting with enlarged lymph nodes (SLL) with or without leukemia are different from those in patients presenting with leukemia (CLL) without enlarged lymph nodes.

Adult↗

PubMed1998

DNA copy number changes in childhood acute lymphoblastic leukemia.

BACKGROUND AND OBJECTIVE: Comparative genomic hybridization (CGH) allows the study of DNA copy number changes in a single hybridization from tumor DNA without any cell culture. Three reports of childhood acute lymphoblastic leukemia (ALL) studied by CGH have been published so far, with somewhat discrepant results. In the present study we performed CGH analysis on 36 patients with childhood ALL. The results were compared to those reported earlier on 157 cases. DESIGN AND METHODS: DNA was extracted from bone marrow specimens from 36 patients with childhood ALL. The tumor and reference DNAs were labeled with fluorescein-isothiocyanate conjugated dCTP and dUTP, and Texas red-conjugated dCTP and dUTP. The hybridizations were analyzed using the ISIS digital image analysis system. RESULTS: The most commonly gained chromosomes were X (42%), 4 (31%), 6 (31%), 10 (36%), 14 (28%) and 18 (33%), and the most common losses were at 9p22-pter (6%) and 12p13-pter (14%). INTERPRETATION AND CONCLUSIONS: The pattern of gains of DNA sequences was very similar in the four reports, but the 9p and 12p deletions were observed only in the present study and one previous report. Our review of the results of 193 patients studied so far shows that the success rate using CGH was close to 100%, whereas cytogenetic analysis failed to reveal any information in 21 patients (11%). Furthermore, in 69 (36%) out of 193 patients CGH gave additional information to the banding analysis. CGH should, therefore, be used to supplement standard cytogenetics in the analysis of childhood ALL patients.

Adolescent↗

PubMed1998

DNA copy number changes in gastrointestinal stromal tumors--a distinct genetic entity.

It is not universally agreed whether gastrointestinal stromal tumors (GISTs) are phenotypical variants of leiomyomas (LM) and leiomyosarcomas (LMS), or whether they belong to a separate phenotypic entity with a different genetic background. This is a summary of our published results from comparative genomic hybridization studies performed in order to solve this question. We studied DNA copy number changes in 32 immunohistochemically well-defined GISTs (13 malignant, 3 borderline, and 16 benign tumors), 14 LM, and 29 LMS. In GISTs, a consistent finding was the loss of DNA copy numbers in chromosome 14q. This loss was detected in 75% of the benign tumors, in 62% of the malignant tumors, and in two out of the three borderline tumors with the minimal overlapping region located to 14q22. The loss was not seen in LM and in LMS it was rare (4 cases, 13%). Only three LM cases showed DNA copy number changes: gains in chromosome 3, 4, 5, 8, and 17. A total of 137 losses and 204 gains were detected in LMS. The most frequent losses were detected in 10q (20 cases, 69%) and 13q (17 cases, 59%). The most frequent gains were detected in 17p (16 cases, 55%). The most frequent high-level amplifications were detected in 17p (7 cases, 24%) and 8q (6 cases, 21%). Our results indicate that DNA copy number losses in 14q are an early change during the oncogenesis of GISTs. Moreover, the pattern of the demonstrated DNA copy number changes suggests that GISTs are a phenotypic and genetic entity separate from leiomyomas and leiomyosarcomas.

Chromosomes, Human, Pair 10↗

PubMed1997

BCL2 overexpression associated with chromosomal amplification in diffuse large B-cell lymphoma.

Gene activation by translocation between an oncogene and an immunoglobulin heavy-chain gene, which leads to increased expression of the oncoprotein, is a well-known mechanism in the genesis of B-cell lymphomas. In contrast, the role of gene amplification in activation of oncogenes in non-Hodgkin's lymphomas is poorly characterized. To study the BCL2 amplification we performed comparative genomic hybridization (CGH), Southern blot hybridization, Western analysis, immunohistochemistry, metaphase fluorescence in situ hybridization, and chromosome analysis on 26 cases of diffuse large B-cell lymphoma (large noncleaved cell lymphoma). The gain or high-level amplification of 18q was found in eight tumors (31%) by CGH, and Southern analysis revealed BCL2 amplification in these cases, but not in the cases with normal chromosome 18 or t(14;18)(q32;q21). Western immunoblot analysis and immunohistochemistry revealed a high-level expression of BCL2 protein in the cases with BCL2 amplification and t(14;18)(q32;q21). However, translocation (14;18)(q32;q21) was not detected in any of the cases with BCL2 amplification. Therefore, our results suggest that amplification of the BCL2 gene is an important mechanism for BCL2 protein overexpression in diffuse large B-cell lymphoma.

Adult↗

PubMed1997

Prognostic value of metaphase-fluorescence in situ hybridization in follow-up of patients with acute myeloid leukemia in remission.

The presence of residual leukemic cells was studied using metaphase-fluorescence in situ hybridization (FISH) in 22 patients with acute myeloid leukemia treated with chemotherapy only or chemotherapy followed by allogeneic bone marrow transplantation. The patients were followed up during their complete remission (CR) for 4 to 108 months (median, 21 months). A total of 88 BM samples was studied. In most of the samples more than 1,000 metaphase cells were analyzed. Residual leukemic cells were detected in 9 of 22 patients (41%). All patients who had an increasing and/or persisting level of abnormal cells in two or more subsequent samples or whose initial samples contained more than 1% of abnormal cells relapsed with one exception, in whom the later subsequent samples showed disappearance of abnormal cells. The time span before the first positive sample seems to be insignificant with regard to the outcome of relapse. Absence or single occurrence of abnormal cells followed by their disappearance was in agreement with CR in all the cases (16 patients). Our results indicate that metaphase-FISH is a reliable tool in the quantitation of residual leukemic cells and provides valuable prognostic information for patients with AML.

Adult↗

PubMed1997

Complexity of 12q13-22 amplicon in liposarcoma: microsatellite repeat analysis.

The 12q13-22 amplicon from four liposacroma specimens evaluated by comparative genomic hybridization was studied analyzing 55 microsatellite markers by PCR. All four specimens were informative in at least 34 loci; an amplification or allelic imbalance was identified with four to 17 markers. The amplicons were discontinuous; there were non-amplified marker loci between the amplified marker loci. These findings indicate the presence of separate amplicons in the 12q13-22 region. Evidence of the concomitant gain of one allele and loss of the other allele was found with several markers in one tumor and with one marker in two tumor specimens. Southern blotting showed amplification of CDK4 and MDM2 in all four specimens.

Alleles↗