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

The ING1 is a newly cloned putative tumor-suppressor gene, which is involved in the p53 signaling pathway. We found decreased expression of ING1 mRNA in 4 of 5 T-cell lines and 5 of 11 B-cell lines including two Burkitt lymphomas and two myelomas. These observations suggest that decreased ING1 expression might play an important role in the development or progression of some lymphoid tumors. Polymerase chain reaction-SSCP and sequencing analyses found neither point mutations nor small deletions in the ING1 gene, suggesting that decreased expression is due to transcriptional or post-transcriptional mechanisms.
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PMID:Decreased expression of p33ING1 mRNA in lymphoid malignancies. 1057 81

We have developed a new assay, ISET (isolation by size of epithelial tumor cells), which allows the counting and the immunomorphological and molecular characterization of circulating tumor cells in patients with carcinoma, using peripheral blood sample volumes as small as 1 ml. Using this assay, epithelial tumor cells can be isolated individually by filtration because of their larger size when compared to peripheral blood leukocytes. ISET parameters were defined using peripheral blood spiked with tumor cell lines (HepG2, Hep3B, MCF-7, HeLa, and LNCaP). ISET can detect a single, micropipetted tumor cell, added to 1 ml of blood. We also demonstrate that fluorescence in situ hybridization can be used to perform chromosomal analyses on tumor cells collected using ISET. Polymerase chain reaction-based genetic analyses can be applied to ISET-isolated cells, and, as an example, we demonstrate homozygous p53 deletion in single Hep3B cells after filtration and laser microdissection. Finally, we provide evidence for the in vivo feasibility of ISET in patients with hepatocellular carcinoma undergoing tumor resection. ISET, but not reverse transcriptase-polymerase chain reaction, allowed analysis of cell morphology, counting of tumor cells, and demonstration of tumor microemboli spread into peripheral blood during surgery. Overall, ISET constitutes a novel approach that should open new perpectives in molecular medicine.
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PMID:Isolation by size of epithelial tumor cells : a new method for the immunomorphological and molecular characterization of circulatingtumor cells. 1062 54

The diagnosis and follow-up of patients with bladder cancer rely on invasive procedures (cystoscopy with biopsy). Polymerase chain reaction (PCR)-based technologies may allow the sensitive detection of cancer-related genetic mutations in exfoliated tumour material, potentially allowing the development of less invasive techniques. This pilot study investigated the feasibility of detecting mutations in exons 5-8 of the p53 gene using single-stranded conformational polymorphism (SSCP) analysis in bladder-washing specimens from patients with bladder cancer. Bladder-washing samples (31) were collected from patients (27) with bladder cancer. An abnormal additional SSCP band was detected in five samples from five different patients suggesting the presence of a p53 mutation. In all five cases the same abnormal SSCP pattern was demonstrated in samples of the corresponding bladder tumour. In one case bladder washings were available from the same patient on two separate occasions with one washing demonstrating a mutation and the other not. In two further cases a mutation was demonstrated in the bladder tumour but not in the corresponding washing. It is concluded that it is possible to detect and characterize p53 mutations in bladder-washing samples from patients with bladder cancer. Improved sensitivity in detecting mutations in a sample containing a mixture of normal and malignant cells may lead to the clinical applicability of molecular methods of disease monitoring.
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PMID:p53 mutations as a marker of malignancy in bladder washing samples from patients with bladder cancer. 1063 80

B-Myb is a transcription factor belonging to the myb family, whose activity has been associated with augmented DNA synthesis and cell cycle progression. We showed recently that B-Myb autoregulates its own expression through promoter transactivation. We report in this study that CDK9, the cyclin T associated kinase, which phosphorylates and activates RNA-Polymerase II, suppresses B-Myb autoregulation through direct interaction with the carboxyl-terminus of the B-Myb protein. Down-regulation of the transactivating ability of B-Myb is independent of the kinase activity of CDK9, because a kinase deficient mutant (dn-CDK9) also represses B-myb gene autoregulation. Overexpression of CDK9 did not result in suppression of p53-dependent transactivation or inhibition of the basal activity of the promoters tested so far, demonstrating that CDK9 is a B-Myb-specific repressor. Rather, transfection of the dominant negative dn-CDK9 construct inhibited the basal activity of the reporter genes, confirming an essential role for CDK9 in gene transcription. In addition, Cyclin T1 restores B-Myb transactivating activity when co-transfected along with CDK9, suggesting that the down-regulatory effect observed on B-Myb is specifically due to CDK9 alone. Thus, our data suggest that CDK9 is involved in the negative regulation of activated transcription mediated by certain transcription factors, such as B-Myb. This may indicate the existence of a feedback loop, mediated by the different activities of CDK9, which links basal with activated transcription.
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PMID:Physical interaction between CDK9 and B-Myb results in suppression of B-Myb gene autoregulation. 1065 84

Previous studies have emphasized the usefulness of DNA ploidy measurement and Human Papillomavirus (HPV) detection as prognostic markers in low grade cervical lesions. We addressed the eventual relationship between HPV type, DNA profile, and p53 tumor suppressor protein expression in anal condylomata acuminata to eventually determine parameters which may be considered as predictive risk factors for the development of cancer. DNA ploidy was assessed by image cytometry after Feulgen staining of contiguous serial sections of 45 anal condylomata acuminata without atypia containing HPV detected by in situ hybridization and Polymerase Chain Reaction (PCR). p53 expression was detected by immunohistochemistry. DNA aneuploidy was found in 53.3% of these lesions, 48.9% containing non oncogenic HPV types 6 and/or 11 and 4.4% harbouring HPV types 11 and 18. The DNA diploid lesions were all associated with non oncogenic HPV types 6 and/or 11 and one case also contained HPV type 33. There was no significant correlation between the detection of DNA aneuploidy and the presence of immuno-detected p53. DNA aneuploidy was not related to the presence of oncogenic HPV in anal condylomata acuminata. The DNA aneuploid profile frequently observed, especially in lesions associated with non oncogenic HPV types, is not yet well explained and cannot be considered as a prognostic factor. In contrast, a more intensive clinical follow-up should be proposed in patients with oncogenic HPV associated to DNA aneuploidy.
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PMID:Human papillomaviruses and DNA ploidy in anal condylomata acuminata. 1066 98

Eighty-seven untreated primary oral squamous cell carcinomas (SCCs) associated with betel quid and tobacco chewing from Indian patients were analysed for the presence of mutations in the commonly shared exon 2 of p16INK4alpha/p19ARF genes. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequencing analysis were used to detect mutations. SSCP analysis indicated that only 9% (8/87) of the tumours had mutation in p16INK4alpha/p19ARF genes. Seventy-two tumours studied here were previously analysed for p53 mutations and 21% (15/72) of them were found to have mutations in p53 gene. Only one tumour was found to have mutation at both p53 and p16INK4alpha/p19ARF genes. Thus, the mutation rates observed were 21% for p53, 9% for p16INK4alpha/p19ARF, and 1% for both. Sequencing analysis revealed two types of mutations; i) G to C (GCAG to CCAG) transversion type mutation at intron 1-exon 2 splice junction and ii) another C to T transition type mutation resulting in CGA to TGA changing arginine to a termination codon at p16INK4alpha gene codon 80 and the same mutation will alter codon 94 of p19ARF gene from CCG to CTG (proline to leucine). These results suggest that p16INK4alpha/p19ARF mutations are less frequent than p53 mutations in Indian oral SCCs. The p53 and p16INK4alpha/p19ARF mutational events are independent and are mutually exclusive suggesting that mutational inactivation of either p53 or p16INK4alpha/p19ARF may alleviate the need for the inactivation of the other gene.
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PMID:The p16INK4alpha/p19ARF gene mutations are infrequent and are mutually exclusive to p53 mutations in Indian oral squamous cell carcinomas. 1067 93

We determined the prognostic role of K-ras mutation in tumor tissue of patients with refractory colon cancer who received Marimastat (BB2516). DNA was extracted from paraffin-stored tumor tissue of 27 patients who previously failed 5-fluorouracil and were treated with BB2516. The presence of K-ras mutation was characterized by Polymerase Chain Reaction using ras- and p53-specific primers. ras and p53 oncoprotein expression was analyzed by an automated biotin-avidin immunoproxidase technique. Seventeen patients had a normal K-ras sequence and 10 patients had a K-ras mutation. Median survival of patients with a normal ras sequence was 330 days from the time of BB2516 treatment compared with 160 days for patients with a K-ras mutation (p = 0.0442, Wilcoxon; 0.0130 Log-Rank). No differences in age, sex, cancer stage, surgical treatment, or chemotherapy treatment were observed. Abnormalities involving ras expression did not affect survival. By comparison, median survival for patients with p53 mutation or p53 overexpression was both 158 days after BB2516 treatment. Patients having both K-ras and p53 mutations had the poorest median survival of 113 days (p = 0.035). There is a suggestion by univariate analysis that the presence of a K-ras mutation may predict survival in patients with progressive colon cancer. Further assessment with larger patient numbers and multivariate analysis is indicated.
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PMID:Prognostic role of K-ras in patients with progressive colon cancer who received treatment with Marimastat (BB2516). 1075 86

Mdm2, localized on chromosome 12, is considered a negative regulator of p53 function and seems to play a role in the pathogenesis of a variety of tumors. The mdm2 amplification in advanced-stage gastric carcinoma has not yet been investigated. Mdm2 amplification was determined in 43 gastric carcinomas, and the genetic results were correlated with mdm2 protein expression, p53 alterations, and clinicopathologic data. The tumors were classified according to Lauren: 20 intestinal-type tumors, 19 tumors of diffuse growth inclusive of a primary small cell carcinoma, and 4 carcinomas with mixed differentiation. Staging was based on the pTNM classification system. Mdm2 and p53 were demonstrated by immunohistology on formalin-fixed and paraffin-embedded tumor tissue. The mdm2 oncogene was amplified by nonradioactive hybridization of tumor DNA with an mdm2 cDNA probe. The Southern blots were evaluated densitometrically. For p53 mutation screening, we analyzed the highly conservative regions of the p53 gene (exons 4 to 8) with the use of the polymerase chain reaction-single-strand conformation polymorphism technique. Polymerase chain reaction products with band shifting were directly sequenced. Mdm2 amplification was demonstrated in 18 tumors (41.8%). The mdm2 gene was amplified more frequently in carcinomas with a diffuse growth pattern. Gastric carcinomas of the intestinal type, however, showed a higher frequency of p53 alterations. There was no statistical significance of the molecular genetic and immunohistologic results of the mdm2/p53 status to staging as well as to age and sex of the patients. The mdm2/p53 pathway is a part of the carcinogenesis of gastric carcinoma. Only approximately 20% of gastric carcinomas failed to show mdm2 and/or p53 alterations. The upregulation of the mdm2 oncogene and the accompanying inactivation of the tumor suppressor gene 53 seem to play a role above all in carcinomas of the diffuse type.
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PMID:Mdm2 gene amplification in gastric cancer correlation with expression of Mdm2 protein and p53 alterations. 1087 65

The isolation of p53 immunostain positive cells from histological sections for molecular genetic studies is a difficult task, especially if there are few positive cells. To eliminate contaminating DNA from p53 negative cells, which can obscure the results of molecular assays, a variation on the technique of immunohistoselective sequencing was developed. This is a highly selective approach, whereby immunostained sections of formalin fixed, paraffin wax embedded tissue are exposed to ultraviolet irradiation to damage the DNA in p53 negative cells. The DNA in positive cells remains unaffected because the dark immunostain protects their nuclei from ultraviolet light. Polymerase chain reaction single strand conformation polymorphism of samples enriched with p53 immunostain positive cells has shown that this method can produce pure samples of mutated DNA. The isolation of DNA from minority immunostain positive cells allows a wide range of molecular analyses to be carried out on these samples, which would otherwise be hampered by the problem of contaminating background cells.
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PMID:Selective genetic analysis of p53 immunostain positive cells. 1089 37

Alveolar soft part sarcoma (ASPS) is a rare malignant neoplasm characterized by slow growth and indolent behavior. The role of proliferative markers and tumor suppressor genes is unknown in these tumors. To investigate their potential role in diagnosis and prognosis, we studied 13 cases of primary ASPS and 14 metastases and correlated them with clinicopathologic parameters. Immunohistochemistry was performed with anti-p53 and anti-Ki-67 antibodies. Polymerase chain reaction after tumor microdissection was performed to search for possible loss of heterozygosity in chromosomes 1p, 9p, 17q, 22q, and TP53 to identify possible changes that may clarify the histogenesis of these tumors. Four of five (80%) primary ASPS cases were positive for Ki-67 and all of them developed later metastases. One patient whose tumor did not stain for Ki-67 remained free of disease for 9 years. Eleven of 13 (85%) metastases were positive for Ki-67; however, there was no correlation with final outcome. All the primary ASPS cases analyzed for p53 yielded negative results, but two (15%) of 13 metastases were weakly positive. There was no correlation of these markers with prognosis or clinicopathologic parameters. No loss of heterozygosity was found except in one of nine (11%) informative metastases for D1S165 (at 1p36). Our preliminary data suggest that Ki-67-positive immunostaining may be a prognostic indicator for the development of metastases in ASPS.
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PMID:Alveolar soft part sarcoma: the role of prognostic markers. 1091 82


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