Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    p53 gene mutations and expression of p53 and mdm2 proteins in invasive breast carcinoma (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 388-394 
    Details
    ISSN: 1432-1335
    Keywords: Key words p53 ; mdm2 ; p53 gene mutation ; Breast carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the study was to analyze p53 gene mutations and the expression of p53 and mdm2 proteins in 31 randomly selected invasive breast carcinomas. The results were then correlated with tumor grade, stage, estrogen receptor status, nodal status, and DNA ploidy. The expression of the proteins p53 and mdm2 was determined immunohistochemically using formalin-fixed, paraffin-embedded material. Screening for p53 mutation involved analysis of the highly conserved regions of the p53 gene (exons 5–9) by the polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) technique. PCR products with band shifts were directly sequenced. Immunohistochemical staining of p53 was positive in 9 cases (29.0 %), only 2 of which showed a p53 gene mutation. These were identified as a C→G transversion at the second position of codon 278 in exon 8 and an A→G transition at the second position of codon 205 in exon 6. A third case with a mutation was observed (C→T transition, position 1 of codon 250 in exon 7) that did not show p53 immunohistochemically. Of the 9 p53-positive tumors, 2 were moderately differentiated (grade II). The remaining tumors were poorly differentiated (7/9). By contrast, p53-negative carcinomas were well differentiated (grade I) in most cases (P = 0.02). DNA cytometry in 8 of the 9 p53-positive carcinomas revealed an aneuploid stem line. The majority of the p53-negative tumors were diploid (P = 0.01). Mdm2 oncoprotein was detected in 10 tumors (32.2 %), 4 of which were p53-positive, including the 3 with mutations. The grading of the mdm2-positive tumors was moderate or poor, G1 carcinomas were always noted to be mdm2-negative (P = 0.04). Overexpression of p53 protein is a complex mechanism and does not merely indicate the detection of mutations in the p53 gene. This study has shown that p53 expression correlates with tumor grade and DNA ploidy. Mdm2 expression was also associated with the tumor grade. Immunohistological demonstration of the p53 protein alone is insufficient as a basis for comment on the functional state of the p53 gene and gene product. The interrelation between recognition of the p53 protein and gene mutation needs more careful assessment to define their roles in the control of neoplasia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240122
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    p53 gene mutations and expression of p53 and mdm2 proteins in invasive breast carcinoma (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 388-394 
    Details
    ISSN: 1432-1335
    Keywords: p53 ; mdm2 ; p53 gene mutation ; Breast carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the study was to analyzep53 gene mutations and the expression of p53 and mdm2 proteins in 31 randomly selected invasive breast carcinomas. The results were then correlated with tumor grade, stage, estrogen receptor status, nodal status, and DNA ploidy. The expression of the proteins p53 and mdm2 was determined immunohistochemically using formalin-fixed, paraffin-embedded material. Screening for p53 mutation involved analysis of the highly conserved regions of thep53 gene (exons 5–9) by the polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) technique. PCR products with band shifts were directly sequenced. Immunohistochemical staining of p53 was positive in 9 cases (29.0%), only 2 of which showed ap53 gene mutation. These were identified as a C→G transversion at the second position of codon 278 in exon 8 and an A→G transition at the second position of codon 205 in exon 6. A third case with a mutation was observed (C→T transition, position 1 of codon 250 in exon 7) that did not show p53 immunohistochemically. Of the 9 p53-positive tumors, 2 were moderately differentiated (grade II). The remaining tumors were poorly differentiated (7/9). By contrast, p53-negative carcinomas were well differentiated (grade I) in most cases (P=0.02). DNA cytometry in 8 of the 9 p53-positive carcinomas revealed an aneuploid stem line. The majority of the p53-negative tumors were diploid (P=0.01). Mdm2 oncoprotein was detected in 10 tumors (32.2%), 4 of which were p53-positive, including the 3 with mutations. The grading of the mdm2-positive tumors was moderate or poor, G1 carcinomas were always noted to be mdm2-negative (P=0.04). Overexpression of p53 protein is a complex mechanism and does not merely indicate the detection of mutations in thep53 gene. This study has shown that p53 expression correlates with tumor grade and DNA ploidy. Mdm2 expression was also associated with the tumor grade. Immunohistological demonstration of the p53 protein alone is insufficient as a basis for comment on the functional state of thep53 gene and gene product. The interrelation between recognition of the p53 protein and gene mutation needs more careful assessment to define their roles in the control of neoplasia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240122
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    MDM2 amplification and loss of heterozygosity at Rb and p53 genes: no simultaneous alterations in the oncogenesis of liposarcomas (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 532-540 
    Details
    ISSN: 1432-1335
    Keywords: Key wordsMDM2 amplification ; Rb LOH ; p53 LOH ; p53 mutation ; Liposarcoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: The present study aimed to investigate the status of alterations of the MDM2, Rb and p53 genes in a series of 45 liposarcomas. Furthermore, the possible correlation with histological and clinical parameters was studied. Methods: MDM2 amplification was examined by non-radioactive Southern blot hybridization with a human MDM2 cDNA probe. Mutations in the p53 gene were screened by polymerase chain reaction/single-strand conformation polymorphism analysis and direct sequencing. To study loss of heterozygosity (LOH) at the tumor-suppressor genes Rb and p53, we used four polymorphic intragenic Rb markers (introns 1, 17, 20, and 25) and two p53 markers (intron 1 and exon 4). Results: MDM2 amplification was found in 19 of 45 liposarcomas (42.2%). The frequency of LOH in Rb and p53 was nearly identical (22%). In 4 of 9 tumors (44.4%) with LOH, allelic loss was a concurrent event in both genes. Of 45 liposarcomas, 6 (13.3%) showed p53 mutations. Overall, alterations of the p53/MDM2/Rb pathway occurred in 30 of 45 liposarcomas (66.6%). In contrast to myxoid and pleomorphic variants, well-differentiated liposarcomas were characterized by a high frequency of MDM2 amplification, a lack of LOH of Rb and p53, and p53 mutations. Conclusions: Obviously MDM2 amplification and LOH at the Rb and p53 genes do not occur simultaneously in the oncogenesis of liposarcomas, as is the case for MDM2 amplification and p53 gene mutations (with one exception). We suggest that well-differentiated, myxoid and pleomorphic liposarcomas are characterized by a different pattern of molecular alterations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050211
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...