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)

Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor, has been implicated in bladder cancer angiogenesis. To examine its role more clearly, we have quantified and localized its expression using Western analysis and immunohistochemistry in a series of 105 bladder cancers. We have also assessed the relationship between TP expression and other tumor parameters including quantitative angiogenesis, p53 status, ploidy, and survival. By Western analysis, TP expression was 5-fold higher in tumors than in normal bladder samples (P < 0.02). Expression was 15-fold higher in invasive tumors than in normal bladder (P < 0.001) and 8-fold higher than in superficial tumors (P < 0.005). Immunohistochemistry of the tumors showed TP was present in the neoplastic epithelium in 27% of the tumors, in the inflammatory cells in 72% of the tumors, in stromal cells in 30% of the tumors, and in tumor-associated endothelium in 11% of the tumors. Expression by Western blotting and immunohistochemistry was significantly up-regulated in tumors compared with normal bladder (P < 0.05). Tumor cell TP expression correlated with tumor grade (P < 0.02), but there was no correlation between tumor cell TP expression and tumor stage (P = 0.46), ploidy (P = 0.52), p53 expression (P = 0.9), tumor vascularity (P = 0.8), relapse-free survival (P = 0.57), or overall survival (P = 0.94). TP protein is expressed in bladder cancers, and expression is associated with an aggressive phenotype. Because TP can activate a number of cytotoxic agents, it provides a potential therapeutic target in bladder cancer.
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PMID:Expression of the angiogenic factor thymidine phosphorylase/platelet-derived endothelial cell growth factor in primary bladder cancers. 884 Oct 1

The objective of this study was to characterize the alterations of 9p21 and TP53 in Korean transitional bladder cancer and to assess the relationship between the histopathologic parameter and the alteration of these genes. Allele loss in 29 surgically resected transitional cell carcinoma was examined by using the multiplex PCR with 7 and 1 microsatellite markers for 9p21 and TP53, respectively. Twenty-one (72%) demonstrated allele loss at 9p21 and/or TP53. Deletion at the 9p21 region was detected in 17(61%) of 28 informative cases at one or more loci, and LOH at TP53 was found in 12(55%) of 22 informative cases. Of 7 microsatellite markers for 9p21, allele loss occurred the most frequently at locus D9S162(69%) and D9S104(69%). Additionally, hemizygous deletion was slightly more common than homozygous deletion. Deletion at 9p21 and TP53 was not related with increased grade. These results suggest that the alteration of 9p21 may be an early event in the development of Korean bladder cancer, while p53 gene may be involved in early event of some bladder cancers as well as in their late events.
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PMID:Deletions of 9p21 and TP53 in bladder cancer. 884 5

Bladder cancer manifests many different forms, ranging from superficial to aggressive muscle invasion, which suggests that various genetic alterations are responsible. Several attempts have been made to establish correlations between specific genetic alterations and various grades of the disease. Numerous types of chromosomal abnormalities have been observed, involving [1p, 1q, 2q, 3p, 4p, 5q, i(5p), +7, +8, 8p, 9p, 9q, 10q23-25, 11p, 11q, +11, 13q, 14q, 17p, 18q, 21q, and Y]. In addition, p53 mutations and loss of heterozygosity on various chromosomes have recently begun to shed light on the molecular pathways of transitional cell carcinomas of the bladder. We have begun to focus on specific genomic sites (especially 9q), although the heterogeneity of the disease and the variable presentation suggests divergent progression pathways. When the genetic basis of bladder cancer is fully understood, new diagnostic and therapeutic strategies will be developed, which in turn may promote better clinical management by pathologists and urologists.
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PMID:Genetics of bladder cancer. 887 57

An understanding of the biological significance of the multiple genetic alterations identified in clinical bladder cancers to the stepwise pathogenesis of the disease is evolving. Alterations in p53 and pRb, products of the chromosomes 17p13 TP53 and 13q14 RB tumor suppressor genes, occur in approximately 50% and approximately 33% of bladder cancers respectively, and are associated with later stage, higher grade disease. p53 and pRb alterations are also known to occur in early stage bladder carcinoma in situ where they are thought to represent a poor prognosis for tumor progression. Allelic loss of genes on 9p21 occurs in approximately 50% of bladder cancers, but whether the only critical gene in this region is the CDKN2/p16 cyclin/CDK inhibitor is at present uncertain. Amplification and/or overexpression of the oncogenes epidermal growth factor receptor and erbB2 are associated with later stage disease. Finally, recent findings generated using in vitro transformation systems with human uroepithelial cells provide strong evidence that loss of genes on 3p, which occurs in approximately 20% of bladder cancers, and/or gain of genes on 20q play an important role in blocking HUC cellular senescence. This latter phenotype should represent a critical step in oncogenesis, as cells that do not senesce can survive to accumulate the multiple genetic alterations associated with invasive and metastatic bladder cancers. Further understanding of the biochemical mechanisms underlying these genetic changes will provide the additional information needed to design better strategies for bladder cancer intervention and treatment.
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PMID:A molecular genetic model of human bladder cancer pathogenesis. 889 68

In order to ascertain the role of arylamines in the induction of bladder cancer in smokers, and to assess the contribution of the metabolic phenotype to cancer risk, studies of molecular epidemiology have been conducted. A number of investigations have reported that "slow" acetylators are at higher risk of bladder cancer, especially subgroups occupationally exposed to arylamines. We present the results of studies that investigated markers of both internal dose (hemoglobin adducts, urinary mutagenicity), and genetically determined susceptibility (metabolic polymorphism) among smokers. Levels of ABP-hemoglobin adducts were elevated in smokers of black (air-cured) tobacco compared to smokers of blond tobacco, and "slow" acetylators showed higher levels than "fast" acetylators. Further, a combination of slow acetylator and fast oxidizer phenotype was associated with the highest level of ABP-hemoglobin adduct. Thus the determination of both phenotypes may allow to better predict the risk of bladder cancer than using the "slow" acetylator phenotype alone. Further investigations in this field will consider the occurrence of mutational spectra (hotspots) in relevant genes (e.g.p53 or p16) to ascertain whether tobacco-related carcinogens induce specific mutations.
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PMID:Molecular epidemiology of bladder cancer. 896 22

Management of Transitional Cell Carcinoma (TCC) of the bladder depends on clinicopathological parameters at initial presentation. These criteria are insufficient predictors because of tumor heteterogeneity. Progress in tumor biology suggest that molecular markers may be used to dismember bladder cancer according to their biological behavior. Evidences have accumulated that cancer result from accumulation of molecular defect specially on tumor suppressor genes. In this respect we studied by mean of immunohistochemistry the prognostic value of p53 nuclear overexpression using monoclonal antibody P1801. The study was performed on 114 TTC and 13 normal bladders. Nuclear straining was quantified using an eye piece reticule at magnification 400x. Scoring was determined counting 500 nuclei in 3 to 5 arbitrary fields. Results between stage, grade and percentage of stained nuclei are as follow: TA 0,92-T1 0,144-T2 0,354-T4 0,622-G1 0,105-G2 0,212-G3 0,406. Comparison of mean nuclear straining between group with and without progression indicates a threshold of 16% for p53 nuclear overexpression. Using this limit there is a significant progression free survival rate for the all group (p < 0,0001) and for the group of superficial tumors (p = 0,0007). Multivariate analysis using stepvise logistic regression indicate a p53 prognostic value independent from stage and grade (OR 23,4). This result indicates that p53 overexpression which can be determined on routine preparation has a strong prognostic value and a certain clinical utility.
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PMID:[Evaluations of protein p53 overexpression in cancer of the bladder: prognostic value]. 897 42

Occurrence or specific types of mutations found in oncogenes or tumor suppressor genes may partially be determined by activities of toxifying or detoxifying enzymes, such as glutathione S-transferases (GST) M1 and T1, arylamine N-acetyltransferase (NAT2), microsomal epoxide hydrolase, and the cytochrome P-450 enzymes 2D6, 1A1, 2A6, and 2E1. In an explorative observational study, 69 bladder cancer patients were analysed for acquired mutations in the p53 tumor suppressor gene. The same patients were studied for the polymorphic traits of xenobiotic metabolism given above which were characterized from blood cell DNA by molecular methods. In 20 patients, single point mutations in p53 were detected whereas five patients carried two mutations; thus in total 25 mutations were detected. Twelve of these were G:C-->A:T transitions, six were A:T-->G:C transitions and seven were transversions (three G:C-->T:A, two A:T-->T:A, one G:C-->C:G, and one A:T-->C:G). There was no correlation between the types of p53 mutations and lifetime smoking or occupational history. In correlation with xenobiotic metabolism, 86% of the seven transversion mutations were found in homozygously deficient individuals for GSTM1 compared to only 44% of GSTM1 deficiency in the carriers of the 18 transition mutations of p53 (p = 0.06). A similar trend was seen for NAT2: six of the seven carriers of transversion mutations had two slow NAT2 alleles. No apparent associations were seen for the other polymorphic traits which were studied. In conclusion, low or deficient activities of two conjugating enzymes of foreign compound metabolism, GSTM1 and NAT2, may influence types of acquired mutations in p53 in bladder cancer.
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PMID:Polymorphic enzymes of xenobiotic metabolism as modulators of acquired P53 mutations in bladder cancer. 901 3

Bladder cancer is the result of a clonal expansion of cancer cells in which multiple genetic alterations have accumulated. Point mutations of the p53 gene are frequently observed in bladder cancer. Loss of a retinoblastoma (Rb) allele is also common in bladder cancer. Recent data have shown frequent loss of heterozygosity (LOH) and homozygous deletion of 9p21, including the region of p16INK4A, a putative tumor suppressor gene, in bladder cancer. LOH is also observed frequently at several other chromosome regions in bladder cancer. These genetic changes have proved useful as clonal markers in the detection of cancer cells in urine. Because of their complexity, most molecular diagnostic approaches are not considered promising cancer screening tools in patients or high-risk populations. However, a new molecular approach, the examination of microsatellite alterations in bladder cancer and urine specimens, is a promising screening tool for the disease. The common genetic alterations in bladder cancer and their use as clonal markers in screening or diagnosis strategies will be discussed.
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PMID:Genetic alterations as clonal markers for bladder cancer detection in urine. 902 18

Immunoreactivity of bcl-2, p53, the epidermal growth factor (EGFr) and Ki-67 (MIB-1) proteins was assessed by immunohistochemistry in 185 patients with superficial bladder cancer (SBC) in order to evaluate their usefulness as indicators of tumor progression. Forty-one percent of the tumors were bcl-2 positive, 36% of them were positive for p53 (over 20% of nuclei), while 41% were positive for EGFr, and 30% of the tumors were MIB-1 positive (proliferation index > 15%). Immunoreactivity of all analyzed proteins was highly significantly related to tumor grade and stage. Tumors which were bcl-2, p53 or EGFr positive were also rapidly proliferative (MIB-1 score >15%). The obtained results suggest that all analyzed proteins may have prognostic significance in SBC. The prognostic value of the abnormal immunolabeling of the analyzed proteins will be established after an adequate follow-up period of this same cohort of patients.
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PMID:Immunoreactivity of bcl-2, p53 and EGFr is associated with tumor stage, grade and cell proliferation in superficial bladder cancer. Finnbladder III Group. 907 39

Overexpression of p53, as determined by immunohistochemical staining with the murine monoclonal antibody DO7, was determined in specimens of 46 primary superficial transitional cell bladder tumours (14 TaG2, 10 T1G2, 22 T1G3). A colon cancer specimen served as a positive control and normal mesenchymal cells in the specimens served as an internal negative control. An exceptionally high proportion 36/46 (78%) of the specimens were found to stain positively for p53 in over 20% of the cell nuclei. After a median follow-up of 7 years, ten patients developed progressive disease. Of these ten patients nine demonstrated p53 positivity, resulting in a sensitivity of 90%. However, 27 of the overall 36 patients (75%) with p53-positive tumours did not progress to a higher stage or metastatic disease. These findings suggest that p53 overexpression is not of predictive prognostic value in superficial transitional cell carcinoma. With 7 of 14 specimens (50%) of Ta tumours overexpressing p53, the results were suggestive of p53 mutation being an early event in carcinogenesis. When the threshold was set at 50% of the cell nuclei overexpressing p53, 16/46 (35%) classified as p53 positive. Of the 16 tumours staining positively for p53, 7 (46%) progressed and 9 (56%) did not. None of the Ta and 16 (50%) of the T1 tumours classified as positive. This more stringent definition of positivity still does not identify p53 positivity as a single prognostic factor. With 50% of T1 tumours classifying as positive, we still find that p53 mutation may be an early event in carcinogenesis of bladder cancer.
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PMID:Immunohistochemical determination of p53 overexpression. An easy and readily available method to identify progression in superficial bladder cancer? 907 54


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