Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in the tumor-suppressor gene p53 are frequently acquired during the course of malignant development of human tumors. Recently, constitutional heterozygous mutations in p53 exon 7 have been identified as the primary cause of cancer predisposition in cases of the familial Li-Fraumeni cancer syndrome. These findings underline the need for extensive mutation screening in families with high cancer incidence. This report describes the detection and follow-up by two-dimensional single-strand conformation polymorphism analysis (2DSSCP) of a new germline mutation of p53 exon 8 in a case of suspected Li-Fraumeni syndrome. Although a high cancer incidence had been reported in the family history of the father of siblings suffering from brain tumor and rhabdomyosarcoma, a constitutional heterozygous p53 mutation was identified only in the affected children. Retrospective analysis of archival tissue of a half-sister who died several years ago from a tumor of previously uncertain diagnosis revealed the same mutation. The mutation had therefore occurred in the germ cells of the mother, who thus appears to be a mosaic. The cancer predisposition of the paternal ancestors must have been due to other factors.
 ...
PMID:p53 mosaicism with an exon 8 germline mutation in the founder of a cancer-prone pedigree. 135 93

We describe the cytopathological picture of a cutaneous rhabdomyosarcoma located in the left nasal furrow of a 4-mo-old girl, some of whose close relatives have died or suffered from different types of neoplasias (Li-Fraumeni syndrome). We believe that the cytological picture is highly characteristic and rules out other round cell tumours of childhood. We underline the usefulness of FNAC in dermatology and strongly advocate the introduction of this technique into the diagnostic armoury of every dermatologist.
 ...
PMID:Infantile cutaneous rhabdomyosarcoma (Li-Fraumeni syndrome): cytological presentation of fine-needle aspirate biopsy, report of a case. 146 41

The p53 gene was examined in primary or metastatic tumors from six patients with rhabdomyosarcoma (RMS) and in five RMS cell lines by screening methods including single-strand conformation polymorphism analysis, the RNase protection assay, sequencing of complementary DNA subclones, and Southern blotting. Six original tumors were of embryonal histology, four alveolar, and one mixed. p53 mutations were identified in four of the six tumors or cell lines derived from tumors with embryonal histology and in one of the four with alveolar histology. Consistent with p53 allele loss, each mutation was found in the homo- or hemizygous state. One tumor showed a G to C transversion at p53 codon 213 (arginine to proline), and another showed deletion of the entire gene. The p53 mutations in cell lines included a codon 248 C to T transition (arginine to tryptophan) in RD and a codon 280 A to T transversion (arginine to serine) in RH30. The cell line CTR contained a 4-base pair deletion at codons 219/220 in exon 6 with resultant frame shift and premature termination in exon 7. These data support the role of diverse types of p53 mutations in the pathogenesis and/or progression of a significant proportion of cases of childhood RMS.
 ...
PMID:Frequency and diversity of p53 mutations in childhood rhabdomyosarcoma. 155 27

An important role for the p53 gene in neoplastic transformation in vitro and in vivo has been imputed by functional studies and identification of tumor-acquired gene defects or alterations in its expression. To study the generality and mechanisms of p53 alteration in human cancer, we examined 241 tumors of several types for structural aberrations of the locus. Alterations of the gene or its RNA or protein products consistent with loss of function by either recessive or dominant mechanisms were identified among this set uniquely in rhabdomyosarcomas and osteosarcomas. The alterations of p53 in rhabdomyosarcoma tumors included cases with complete deletion of both p53 alleles, complete deletions of one allele with or without point mutation of the remaining allele, and absence of detectable RNA. Similarly, we detected homozygous deletion and lack of expression of p53 RNA or aberrant expression of p53 protein in osteosarcomas. These observations provide strong support for the inclusion of the p53 locus in the group of loci whose functional inactivation by either dominant or recessive modes plays a significant role in human cancer.
 ...
PMID:Mechanisms of p53 loss in human sarcomas. 214 22

We investigated the possibility that a proportion of children with sporadic rhabdomyosarcoma (RMS) carry constitutional mutations of the p53 tumor suppressor gene. 33 patients with sporadic RMS at two large outpatient pediatric oncology clinics submitted blood samples. Genomic DNA was extracted from peripheral blood leukocytes and PCR was used to amplify exons 2-11 of the p53 gene. Amplified genomic DNA was screened for the presence of germline p53 mutations using single-strand conformation polymorphism (SSCP) analysis. The DNA sequence of those samples that showed aberrant migration of bands on SSCP analysis was determined to identify the precise nature of the gene mutations. Patient records were reviewed to assess clinical correlates of the mutant p53 carrier state. Heterozygous constitutional mutations were detected in 3/33 patient samples screened. Two of these missense mutations are located in exon 7 and one in exon 8 of the p53 gene. The presence of mutations was not correlated with tumor histology, stage, or site. However, an association between young age at diagnosis and presence of a constitutional p53 mutation was noted: 3/13 children under the age of 3 yr at diagnosis carried mutations, whereas none of 20 children over 3 yr of age at diagnosis harbored a detectable constitutional mutation. These results in children with RMS corroborates previous findings in other clinical settings suggesting that the mutant p53 carrier state may predispose individuals to malignancy at an early age. Although this study did not assess whether the mutations were preexisting or new germline alterations, assessment of close relatives of RMS patients for cancer risk and predictive genetic testing may be indicated.
 ...
PMID:Germline p53 mutations are frequently detected in young children with rhabdomyosarcoma. 770 67

A family with an aggregation of adrenocortical carcinoma, rhabdomyosarcoma, osteosarcoma, and early onset breast cancer was referred to our laboratory. Because this aggregation was reminiscent of Li-Fraumeni syndrome, germ-line mutation of the p53 tumor suppressor gene was sought in the DNA of two affected members. The highly conserved regions spanning exons 5 to 8 of the p53 gene were screened by a previously validated denaturing gradient gel electrophoresis method. A single base pair deletion at codon 215 was detected in constitutional DNA of the two patients, and in the DNA extracted from an adrenocortical carcinoma tumor specimen of the propositus. This deletion is predicted to lead to the formation of a truncated p53 protein, a relatively rare event in Li-Fraumeni families. The spectrum of tumors observed in this family does not differ markedly from the spectrum observed in families with missense p53 mutations.
 ...
PMID:Single base pair germ-line deletion in the p53 gene in a cancer predisposed family. 803 1

Previous studies have shown that human rhabdomyosarcoma cells are induced to differentiate by TPA, in the absence of appreciable alterations of the muscle regulatory genes and their products (1). The question was addressed whether the tumor suppressor p53 could be a target of TPA action in these cells. Genomic analysis by a Polymerase Chain Reaction/Single-Strand Conformation Polymorphism (PCR/SSCP) and direct sequencing indicate the presence of a mutation in exon VII at codon 248 (C to T transition) and a loss of heterozygosity of p53 gene in human rhabdomyosarcoma cell line (RD). It is here shown that transcription of p53 mRNA strongly decreases in RD cells induced to growth arrest and differentiate by TPA treatment. In these cells immunoprecipitation and immunoblot analysis show that both synthesis and total cellular concentration of the protein are also reduced by TPA. Nevertheless nuclear p53 accumulation is at much higher extent, whereas 32P-orthophosphate labelling, followed by immunoprecipitation, demonstrates a decrease of phosphorylation of both cytoplasmic and nuclear p53. These results indicate that TPA causes a number of alterations of mutant p53, likely mediated through a protein kinase C dependent mechanism, which might impair the transforming ability of mutant p53 in growth-arrested and differentiating RD cells.
 ...
PMID:TPA-induced differentiation of human rhabdomyosarcoma cells involves dephosphorylation and nuclear accumulation of mutant P53. 803 10

Amplification of cellular oncogenes may be important for the development and progression of malignant tumors. In human sarcomas, amplification of several genes located to the q13-14 region of chromosome 12 has been reported. Because the mdm2 protein seems to inactivate the tumor suppressor protein p53, a selective growth advantage of 12q13-14 amplification has previously been assigned to increased copy number and expression of the MDM2 gene. We have analyzed a panel of 98 human sarcomas of different subtypes to characterize the 12q13-14 amplica and determine which of the genes GLI, A2MR, SAS, MDM2, and GADD153 (CHOP) in this region was most consistently amplified. MDM2 was amplified in 9 of the tumors, SAS in 10, GADD153 in 4, GLI in 2, and A2MR in 2. Amplification was, in most cases, associated with increased expression of the corresponding gene. SAS and MDM2 were coamplified in 8 of the tumors, whereas GADD153, GLI, and A2MR were only amplified together with SAS. One liposarcoma showed amplification of MDM2 alone, whereas two osteosarcomas and a rhabdomyosarcoma cell line showed amplification of SAS and GADD153 (CHOP) but not MDM2. It is suggested that the selective target for these amplica may be an as yet unidentified gene localized between SAS and MDM2.
 ...
PMID:Mapping of amplification units in the q13-14 region of chromosome 12 in human sarcomas: some amplica do not include MDM2. 811 20

The entire coding sequence of the p53 gene was analysed for the presence of mutations in 12 families conforming to a restricted definition of Li-Fraumeni syndrome (classic LFS) and nine families with features of LFS conforming to a broader definition. Mutations were detected in seven families. Six were point mutations with one each affecting codons 175, 180, and 220 and three affecting codon 248. The seventh was a deletion/insertion mutation in exon 4. Germline mutations in p53 were a feature of families which included children with rhabdomyosarcoma and/or adrenal cortical carcinoma. Germline p53 mutations were detected in six of the nine families with such tumors. An analysis of these 7 mutations, together with 34 published examples, showed that more than one-half were transitions at CpG dinucleotides, suggesting that the majority of germline p53 mutations may arise as a result of spontaneous events. The most common cancers occurring in the 41 families with germline p53 mutations, in common with classic LFS, were bone and soft tissue sarcoma, breast cancer, brain tumors, leukemia, and adrenocortical carcinoma, although less than one-half of the probands with germline p53 mutations came from classic LFS families. More than one-half of the cancers overall and nearly one-third of the breast cancers were diagnosed before 30 years of age. These observations have important implications for asymptomatic carriers of germline p53 mutations, and there is a need for international collaboration in the development of protocols for the management of such families.
 ...
PMID:Prevalence and diversity of constitutional mutations in the p53 gene among 21 Li-Fraumeni families. 811 19

Loss of function of the p53 tumor suppressor gene by point mutation is the most commonly detected genetic alteration in human cancer. There is growing evidence that amplification and overexpression of the MDM2 gene are alternative mechanisms that also lead to functional inactivation of p53. While p53 mutations and MDM2 amplification have been reported to occur in rhabdomyosarcoma and osteogenic sarcoma, the incidence of MDM2 in other pediatric solid tumors is not known. We therefore tested a series of other pediatric solid tumors for MDM2 gene amplification. MDM2 amplification could not be detected in specimens from 40 Wilms' tumors, 15 neuroblastomas, 12 sarcomas, or 4 hepatoblastomas tested. To determine whether MDM2 amplification was an alternative mechanism of p53 inactivation in adult carcinomas that frequently possess p53 mutations, 68 samples of squamous cell carcinomas of the upper aerodigestive tract, 24% of which were previously shown to contain p53 mutations, were also tested for MDM2 amplification. MDM2 amplification did not occur in any of the tumor specimens tested. These findings suggest that MDM2 amplification may only occur in a limited subset of human tumors. Loss of function of p53 may be an essential event in human tumorigenesis. If so, then other mechanisms of p53 inactivation must occur in those tumors that exhibit neither p53 mutation nor MDM2 amplification.
 ...
PMID:Infrequency of MDM2 gene amplification in pediatric solid tumors and lack of association with p53 mutations in adult squamous cell carcinomas. 826 17


1 2 3 4 5 6 7 8 9 10 Next >>