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  • 1
    Electronic Resource
    Electronic Resource
    The Significance of ras Oncogene Mutation for the Development of Human Breast Cancer (1998)
    Oxford, UK : Blackwell Publishing Ltd
    The @breast journal 4 (1998), S. 0 
    Details
    ISSN: 1524-4741
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Activation of ras oncogenes has been described in various human tumors. Additionally there is strong evidence that ras oncogenes are involved in experimental mammary carcinogenesis. The role of these oncogenes in the development of human breast cancer has not yet been fully clarified.We investigated 45 cases of primary human breast cancer for point mutation in the hot spot regions codon 12 and 13 of exon 1 and codon 61 of exon 2 of H-, K-, and N-ras gene, applying polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique followed by direct sequencing.One case of an invasive ductal breast cancer showed an activation by point mutation in codon 61, exon 2 of the H-ras gene. We could demonstrate a transversion of adenine to thymine leading to an exchange between glutamine and leucine.Our findings suggest that in spite of experimental carcinogenesis the rate occurrence of ras-oncogene activation by point mutation does not play an important role in human breast cancer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1524-4741.1998.420112.x
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  • 2
    Electronic Resource
    Electronic Resource
    p53 gene mutations in soft-tissue sarcomas-correlations with p53 immunohistochemistry and DNA ploidy (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 211-218 
    Details
    ISSN: 1432-1335
    Keywords: Soft-tissue tumors ; p53 gene mutation ; p53 immunohistochemistry ; PCR SSCP analysis ; DNA ploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The significance ofp53 mutations in a group of 67 soft-tissue tumors was examined using single-strand conformation polymorphism and direct sequencing analysis. Molecular findings were correlated with immunohistochemical detection of thep53 protein and DNA ploidy status. Mutations of thep53 gene were detected in 13 (19.5%) out of 67 cases of soft-tissue tumors. Only there were localized outside the conservative regions of thep53 gene. Six mutations were described for the first time in these tumors. Most of the mutations were point mutations in exons 5–8 and, in one case, a deletion at the 3′-splice site of exon 5 could be demonstrated. There was no significant correlation between the occurrence ofp53 mutations and the histological grade, although a high number of mutations were defined in poorly differentiated tumors (grade 3). Molecular finding of ap53 gene mutation and immunohistochemical detection ofp53 expression did not correlate, which may be due to the high percentage of nonsense mutations in our study (50%). We confirm that only DNA sequencing allows a unique identification and differentiation of mutations in thep53 gene. Other factors may be responsible for the detection ofp53 protein in many cases. Histological grade correlated with aneuploidy. The frequency of mutations observed was in accordance with values quoted in the literature. Generally,p53 mutations andp53 overexpression are more likely to represent a late event in the oncogenesis of soft-tissue tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240317
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  • 3
    Electronic Resource
    Electronic Resource
    p53 gene mutations in soft-tissue sarcomas – correlations with p53 immunohistochemistry and DNA ploidy (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 211-218 
    Details
    ISSN: 1432-1335
    Keywords: Key words Soft-tissue tumors ; p53 gene mutation ; p53 immunohistochemistry ; PCR SSCP analysis ; DNA ploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The significance of p53 mutations in a group of 67 soft-tissue tumors was examined using single-strand conformation polymorphism and direct sequencing analysis. Molecular findings were correlated with immunohistochemical detection of the p53 protein and DNA ploidy status. Mutations of the p53 gene were detected in 13 (19.5%) out of 67 cases of soft-tissue tumors. Only three were localized outside the conservative regions of the p53 gene. Six mutations were described for the first time in these tumors. Most of the mutations were point mutations in exons 5 – 8 and, in one case, a deletion at the 3′-splice site of exon 5 could be demonstrated. There was no significant correlation between the occurrence of p53 mutations and the histological grade, although a high number of mutations were defined in poorly differentiated tumors (grade 3). Molecular finding of a p53 gene mutation and immunohistochemical detection of p53 expression did not correlate, which may be due to the high percentage of nonsense mutations in our study (50%). We confirm that only DNA sequencing allows a unique identification and differentiation of mutations in the p53 gene. Other factors may be responsible for the detection of p53 protein in many cases. Histological grade correlated with aneuploidy. The frequency of mutations observed was in accordance with values quoted in the literature. Generally, p53 mutations and p53 overexpression are more likely to represent a late event in the oncogenesis of soft-tissue tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240317
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  • 4
    Electronic Resource
    Electronic Resource
    Expression of multidrug-resistance-associated protein gene in human soft-tissue sarcomas (1996)
    Springer
    Journal of cancer research and clinical oncology 122 (1996), S. 161-165 
    Details
    ISSN: 1432-1335
    Keywords: Soft-tissue sarcoma ; MRP mRNA ; Multidrug resistance ; MDR1 ; RT-PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the mRNA expression of the multidrug-resistance-associated protein gene (MRP) in soft-tissue sarcomas and compared it with the expression of the multidrug resistance gene (MDR1), using the reverse transcriptase/polymerase chain reaction. We investigated 39 samples from 33 cases of soft-tissue sarcomas (11 liposarcomas, 9 malignant fibrous histiocytomas, 6 leiomyosarcomas, 4 malignant schwannomas, 3 fibrosarcomas, 3 synovial sarcomas, and 3 epithelioid sarcomas) and 7 benign softtissue tumors. All samples were obtained prior to chemotherapy. An expression ofMRP mRNA was noted in 56% of soft-tissue sarcoma specimens. The co-expression ofMRP andMDR1 was recognized in 15 samples (38%) (5/11 liposarcomas, 5/9 malignant fibrous histiocytomas, 3/6 leiomyosarcomas, 2/3 fibrosarcomas) and significantly correlated with histological grade (P=0.0165). A positive and significant correlation was found betweenMRP andMDR1 expression in soft-tissue sarcomas (P=0.0013). In benign soft-tissue tumors, 1 chemodectoma and 1 neurothekeoma showed lowMRP expression; however, no case showed co-expression ofMRP andMDR1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366956
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  • 5
    Electronic Resource
    Electronic Resource
    On telomere shortening in soft-tissue tumors (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 165-171 
    Details
    ISSN: 1432-1335
    Keywords: Key words Telomeres ; Soft-tissue tumors ; Telomerase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Specific simple DNA repeats occur at the telomeric ends of mammalian chromosomes. Loss of (G+C)-rich repeats can result in genetic instability, associated with tumorigenesis. So far, data on telomere shortening have not been available for different types of soft-tissue tumors. Methods: Using tumor material and the blood of the corresponding patient, high-molecular-mass DNA was prepared by digestion with proteinase K and extraction with phenol/chloroform. A 10-μg sample of DNA was digested with the restriction enzyme HinfI. DNA fragments were separated in a 0.7% agarose gel, and in-gel hybridization was performed with the telomere-specific repeat probe (TTAGGG)3. Results: Shortening of the telomere repeat was observed in 14/30 soft-tissue tumors; 5 tumors showed elongated telomere repeats, whereas the telomeres appeared unchanged in 11 tumors. Decreased telomere repeat length correlated with advanced age, DNA ploidy, and a higher proliferation index. There was no association between telomere repeat length and tumor grade. Interestingly, in contrast to other entities, all malignant schwannomas and leiomyosarcomas showed significantly reduced telomere lengths. An explanation for the telomere heterogeneity in liposarcomas may include differential telomerase reactivation in well and poorly differentiated tumors. Conclusions: Telomere shortening is frequent but not a uniform phenomenon in different types of soft-tissue tumor. Studies on telomerase activity should be performed in the same cohort of sarcomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050150
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  • 6
    Electronic Resource
    Electronic Resource
    Mutation of p53 with loss of heterozygosity in the osteosarcomatous component of a dedifferentiated chondrosarcoma (2000)
    Springer
    Virchows Archiv 436 (2000), S. 494-497 
    Details
    ISSN: 1432-2307
    Keywords: Key words Dedifferentiated chondrosarcoma ; p53 mutation ; p53 LOH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated a dedifferentiated chondrosarcoma of a 61-year-old woman with an osteosarcomatous high-grade component for p53 alteration. The low-grade cartilaginous and the high-grade osteosarcomatous components of the tumor were macrodissected and evaluated separately by immunohistochemistry and molecular biology. We used PCR-SSCP analysis and direct sequencing to screen exons 4–8 for p53 mutations. The p53 intron 1-polymorphism was investigated for loss of heterozygosity. A functionally relevant p53 missense mutation in codon 193 of exon 6 (A-to-T transversion) with loss of wild-type allele was detected only in the dedifferentiated component. Using the monoclonal antibody DO-1, immunohistochemistry failed to show p53 overexpression. This evidence of p53 mutation may be regarded as at least a co-factor that ”switched” the preexisting low-grade conventional chondrosarcoma to a highly malignant dedifferentiated tumor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050478
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  • 7
    Electronic Resource
    Electronic Resource
    Congenic AB mice: A novel means for studying the (molecular) genetics of aggression (1995)
    Springer
    Behavior genetics 25 (1995), S. 475-482 
    Details
    ISSN: 1573-3297
    Keywords: Aggressive behavior ; congenic mouse strains ; multilocus DNA fingerprinting ; oligonucleotides ; simple repetitive sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Congenic strains (CS) of mice were established to identify genomic regions which are associated with the male behavioral trait “isolation-induced aggression” (iia). For this purpose the trait was backcrossed for 10 generations onto the genetic background of a closely related, but nonaggressive, strain. Brother/sister matings were subsequently performed for 10 generations. Genomic screening for “iia-associated” markers was performed via multilocus DNA fingerprinting with a panel of oligonucleotide probes containing simple tandem repetitive motifs. Pools of DNAs from 10 mice each were composed from inbred generations to minimize residual genetic variability in the CS. The representation of iia-associated DNA fingerprint bands was additionally ascertained by investigating the individual mouse genomes constituting the pools. The CS system may allow rational approaches to the behavioral trait “aggression,” even under various experimental conditions of different environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02253376
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  • 8
    Electronic Resource
    Electronic Resource
    Improved detection of P53 mutations in soft tissue tumors using new gel composition for automated nonradioactive analysis of single-strand conformation polymorphism (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 2849-2851 
    Details
    ISSN: 0173-0835
    Keywords: Polyacrylamide gel electrophoresis ; Single-strand conformation polymorphism ; Automated sequencer ; p53 gene ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We report a new nonradioactive method to detect sequence changes, including single-base substitutions through shifts in electrophoretic mobility using an automated fluorescence sequencer (ALFexpress, Pharmacia, Biotech) connected to external cooling equipment. Single strands were identified by incorporation of fluorescein-labeled primers during amplification and subsequent laser detection at the bottom of the gel. The amplified polymerase chain reaction (PCR) products were heat-denatured and loaded onto a polyacrylamide gel under nondenaturing conditions and strict control of constant low temperature. Peak shifts in the fluorogram indicated mutations. A novel gel composition improved the detection rate for mutations considerably. Automatic analysis of single-strand conformation polymorphism (SSCP) gels saves time and costs, and is highly reproducible. The method was applied for mutation screening in exon 7 of the p53 tumor suppressor gene in DNA of freshly frozen soft tissue tumors. The mutation spectrum and frequency in exon 7 of the p53 gene are discussed with respect to oncogenesis in soft tissue sarcomas.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150181521
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