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)

Twenty-one invasive squamous-cell carcinomas (SCC) of the bladder from Schistosoma-hematobium-infected patients were examined immunohistochemically for the expression of p53, Rb, EGFR and c-erbB-2 proteins; and screened by single-strand conformation polymorphism and sequencing for mutations in the ras (H, N, K) codon hotspots (12, 13, 61) and p53 (exons 4-9) genes. Positive staining for p53, EGFR and c-erbB-2 was reported in 38, 67 and 28% of tumors respectively. Only one of the tumors, the only one that was poorly differentiated, displayed an absence of nuclear Rb staining. Ras alterations were detected in the H-ras gene in 3 tumors, 2 of which harbored a codon-13 (Gly-->Arg) and one a codon-12 (Gly-->Ser) point mutation. p53 mutations were recorded in 12 tumors (57%), 6 of which stained positively for p53. Four tumors had exon-7 mutations (codons 235, 241 and 249; one tumor had 2 exon-7 mutations). Eight tumors were mutated in exon 8 (codons 264, 271, 273, 285, 286, 288 and 294), 5 of which harbored multiple mutations. One tumor had an insertion/deletion event in exon 9. The frequency of detection of over-expression of EGFR and c-erbB-2 in bilharzial-bladder lesions is comparable to that reported in TCC, contrasting with the infrequent loss of Rb expression found in invasive lesions associated with schistosomiasis infection. However, the detection of multiple p53 mutations in these lesions is suggestive of the involvement of a carcinogenic agent with maintenance of preferential activation of the H-ras gene.
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PMID:Molecular events underlying schistosomiasis-related bladder cancer. 762 66

Much of bladder cancer in East Africa and the Middle East is attributed to chronic urinary infection with Schistosoma haematobium ('schistosomiasis'). Most schistosomal bladder cancer (SBC) is squamous cell carcinoma (SCC) and occurs in the fifth decade of life. In contrast, nonschistosomal bladder cancer (NSBC) in Western countries usually occurs in the seventh decade of life and is largely transitional cell carcinoma (TCC). To shed light on the mechanisms underlying these different patterns of bladder cancer we looked for mutations in the p53 gene in SBC from 92 patients in Egypt, where schistosomiasis is hyperendemic. Patients' mean age at presentation of bladder cancer was 49.4 +/- 9.9 years and 90% had a clinical history of schistosomiasis and/or histological evidence of schistosomal eggs adjacent to the carcinoma. There were 53 SCC, 23 TCC, 13 adenocarcinomas and three other carcinomas. Thirty patients had tumours with mutations in exons 5-8 of the p53 gene: 17/53 SCC, 8/23 TCC, 4/13 adenocarcinomas and 1/3 other tumours. Of 19 mutations in SCC, 16 were base pair substitutions (BPS), two were deletions and one an insertion. Two tumours each contained two mutations. Of the BPS, nine were transitions at CpG dinucleotides and two were G-->T transversions. All the mutations in TCC were BPS: four were transitions at CpG dinucleotides and three were G-->C transversions. One TCC had two mutations. Of four adenocarcinomas with mutations, two had transitions at CpG dinucleotides. Of the 30 BPS mutations, 16 were transitions at CpG dinucleotides, of which 12 were C-->T. We combined these 33 mutations with six obtained from Egyptian SCC reported by Habuchi et al. (Cancer Res., 53, 3795-3799, 1993) to compile a mutational spectrum. This was compared with a NSBC spectrum assembled from 118 mutations reported in the literature. The proportion of BPS at CpG dinucleotides was significantly higher in SBC than in NSBC (18/34 versus 25/103, P = 0.003). There was also a bias away from mutations in exons 7 and 8 towards mutations in exons 5 and 6. We suggest that the excess of transitions at CpG dinucleotides in SBC results from nitric oxide (NO) produced by the inflammatory response provoked by schistosomal eggs. NO could produce such mutations directly, by deamination of 5-methylcytosine, and indirectly, following conversion to nitrate, bacterial reduction to nitrite and endogenous formation of urinary N-nitroso compounds. These produce O6-alkylguanines in DNA, leading to very high rates of G:C-->A:T transitions, a process possibly augmented by inefficient repair of alkylated bases at CpG dinucleotides.
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PMID:Mutations in the p53 gene in schistosomal bladder cancer: a study of 92 tumours from Egyptian patients and a comparison between mutational spectra from schistosomal and non-schistosomal urothelial tumours. 776 83

Immunoreactivity for p53 and c-erbB-2 proteins was studied in 31 schistosomal urinary bladder carcinomas and 21 cases of schistosomal cystitis with hyperplastic, metaplastic and/or dysplastic (premalignant) lesions. The results were compared with 30 carcinomas and 21 premalignant lesions of the urinary bladder without schistosomiasis. Abnormal nuclear p53 protein accumulation was found in 17/31 schistosomal and in 15/30 non-schistosomal carcinomas and in 8/21 schistosomal cystitis with premalignant lesions of which five showed hyperplasia. No case of non-schistosomal hyperplasia or squamous metaplasia examined showed p53-positivity. In non-schistosomal carcinomas p53 positivity was significantly associated with tumour grade (grade I-II vs grade III tumours: P = 0.021) and greater age (P = 0.004) while in schistosomal carcinomas no such associations were found. Cytoplasmic membrane-bound positivity for c-erbB-2 oncoprotein was found in comparable percentages in schistosomal and non-schistosomal bladder carcinomas (10%), and in both groups was co-expressed with p53. p53 gene alteration is an important event in the development of both schistosomal and non-schistosomal bladder carcinoma.
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PMID:p53 and c-erbB-2 expression in schistosomal urinary bladder carcinomas and schistosomal cystitis with premalignant lesions. 791 81

The mutation patterns of the p53 tumor suppressor gene have been shown to reflect the specific carcinogen(s) involved, or the epidemiological background in some cancers. To elucidate the impact of cigarette smoking or bilharzial infection on the p53 gene mutation pattern, 61 cases of urothelial cancer from Japan and 7 cases of bladder cancer with schistosomiasis from Egypt were examined for mutations of the p53 gene. In total, p53 gene mutations were detected in 20 Japanese cases (33%) and 6 Egyptian cases (86%). Although the incidence of p53 gene mutation was not significantly influenced by habitual smoking, a different mutation pattern was observed as follows: 4 of 10 mutations in smokers in Japan were A:T to G:C transitions, whereas such mutations were not detected in any of 10 mutations in nonsmokers, or in any of 6 mutations associated with schistosomiasis. Although no specific mutation pattern was detected for the squamous cell carcinomas with schistosomiasis, all 8 base substitutions observed in tumors with squamous cell carcinomas occurred at G:C sites, whereas base substitutions at A:T sites were observed in 33% (6 of 18) of mutations in transitional cell carcinomas. Our results suggest that cigarette smoking may have a significant impact on the mutations of the p53 gene in urothelial cancers. Furthermore, the distinct spectrum of the p53 gene mutation found in tumors with squamous cell carcinomas may reflect their unique etiological backgrounds.
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PMID:Influence of cigarette smoking and schistosomiasis on p53 gene mutation in urothelial cancer. 833 93

Carcinoma of the urinary bladder is the most common malignancy in many tropical and subtropical countries and is mainly due to endemic schistosomal infection. Schistosomiasis-associated bladder cancer defines a characteristic pathology and cellular and molecular biology that differs from urothelial carcinoma of non-schistosomal origin. N-Nitroso compounds are suspected etiologic agents in the process of bladder cancer induction during schistosomiasis. Elevated levels of DNA alkylation damage have been detected in schistosome-infected bladders and are accompanied by an inefficient capacity of DNA repair mechanisms. Consequently, high frequency of G --> A transition mutations were observed in the H-ras gene and at the CpG sequences of the p53 tumor suppressor gene. Genetic changes have also been detected in the c-erbB-1 and c-erbB-2 oncogenes and in the cdkn2 and Rb tumor suppressor genes. The potential application of these mutational patterns in providing a biological marker suitable for the biomonitoring and early detection of this neoplasm could indicate new avenues of approach that might alleviate the problem in the future. It can also assist in elucidating the mechanisms by which schistosomiasis augments human bladder cancers.
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PMID:Molecular and genetic events in schistosomiasis-associated human bladder cancer: role of oncogenes and tumor suppressor genes. 869 35

Cyclophosphamide is a known bladder carcinogen, with cumulative dose directly related to increased risk. There is no consensus, however, on which major cyclophosphamide metabolite (i.e., acrolein or phosphoramide mustard) drives bladder carcinogenesis. We examined 19 cyclophosphamide-related bladder tumors to test the hypothesis that they might contain somatic mutations in the p53 tumor suppressor gene that could link a specific metabolite to the etiology of these cancers. Forty-three % (9 of 19) of the cases had a mutation in p53, with a predominance at G:C bp (7 of 9, 77%), a preference for non-CpG sites (6 of 7, 86%), and frequent G:C-->A:T transitions (5 of 7, 71%). The p53 mutation spectrum of these cyclophosphamide-associated bladder cancers differed significantly from patterns reported for sporadic (P = 0.020), smoking-related (0.043), and schistosomiasis-linked (P = 0.002) tumors but not arylamine-associated neoplasms (P = 0.860). Differences between the cyclophosphamide and arylamine-associated spectra included an unusual degree of clustering of exon 6 mutations (43% versus 17%, respectively) and an absence of multiple mutations in the former. Notably lacking in our series were G:C-->T:A transversions, the principal mutation associated with acrolein. Instead, the mutation spectrum matches the phosphoramide mustard adduction sequences determined by a repetitive primer-extension assay (P = 0.024), indicating that this metabolite might be a key mutagen in cyclophosphamide-related bladder cancer.
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PMID:p53 mutations in cyclophosphamide-associated bladder cancer. 961 Jul 89

Mutations in p53 tumor suppressor gene were examined in 44 Chinese patients with rectal cancer, including 22 cases with advanced schistosomiasis japonica and 22 cases without schistosomiasis. In schistosomal rectal cancer (SRC), 13 mutations were found in 10 cases, which included 11 base-pair substitutions and two deletions. Of 11 base substitutions, nine were transitions and two were transversions and seven of them were located at CpG dinucleotides. In non-schistosomal rectal cancer (NSRC), 13 mutations were found in nine cases, all of which were base-pair substitutions. Of 13 substitutions, 10 were transitions and three were transversions and three of them were located at CpG dinucleotides. The proportion of base-pair substitutions at CpG dinucleotides was higher in SRC patients than in NSRC patients, although this was not statistically significant (P = 0.054). Point mutation was frequent at codon 248 in SRC. A higher frequency of arginine missense mutations was observed in SRC than in NSRC. These observations suggest that the mutations in SRC are the result of genotoxic agents produced endogenously through the course of schistosomiasis japonica.
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PMID:p53 gene mutations in rectal cancer associated with schistosomiasis japonica in Chinese patients. 985 Dec 56

In Egypt and other regions of the Middle East where the trematode Schistosoma haematobium is endemic, bladder cancer is the most common adult cancer. Unlike bladder cancers in Western countries, which are predominantly transitional-cell carcinoma (TCC), these schistosomiasis-associated bladder cancers are predominantly squamous-cell carcinoma (SCC). Our aim was to assess a large series of schistosomiasis-associated bladder tumours for genetic alterations commonly found in TCC in the United Kingdom and the United States. We have carried out a partial allelotype of 70 tumours from patients with schistosomiasis. LOH was found on all chromosome arms studied (3p, 4p, 4q, 8p, 9p, 9q, 11p, 11q, 13q, 14q, 17p, 18q). The most frequent regions of LOH were 9p (65%), 17p (58%), 3p (40%), 9q (39%) and 8p (37%). LOH on 17p, where the TP53 gene is located, was more common in Egyptian TCC than in SCC. Similarly, 8p LOH was more common in TCC than SCC. The most striking difference between this group of tumours and TCCs from the United Kingdom and the United States was the high frequency of 9p LOH in the region of the CDKN2 gene (65%) and the relatively low frequency of 9q LOH (39%); 15 of 43 tumours with LOH of at least one marker on chromosome 9 showed LOH of 9p only. This suggests that a 9p gene, possibly CDKN2, may contribute to the development of the majority of schistosomiasis-associated bladder tumours but that genes on 9q play a much less important role.
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PMID:Partial allelotype of schistosomiasis-associated bladder cancer. 1004 62

Data concerning the expression of p53 in cervical carcinoma, one of the leading cause of death in developing countries, are still confusing. This study was designed to identify p53 in Egyptian cervical carcinoma in an attempt to evaluate its prognostic significance. Eleven chronic cervicitis and 38 invasive carcinoma (31 squamous cell carcinoma (sqcc) and 7 adenocarcinoma, ranging from stage IB to IVB), were stained with the monoclonal antibody anti p53, DO7, using the microwave for antigen retrieval. No immunoreactivity was detected in chronic cervicitis, while nuclear p53 reactivity was detected in all carcinoma and in squamous intra-epithelial lesions (SIL) overlying 8 sqcc. P53 immunohistochemical (IHC) expression was more pronounced in early clinical stages (p=0.007) and in adenocarcinoma compared to sqcc (p=0.015). A positive correlation was present between p53 and heat shock protein 70 (hsp70) expressions (p=0.005). No correlation could be found between p53 expression and tumor infiltrating lymphocytes, the presence or absence of either schistosomiasis or HPV infections. It can be concluded, that in the Egyptian population, p53 immunoreactivity appears to be an early event in cervical neoplasm, and seems to play an important role together with other cell regulatory proteins in the process of carcinogenesis, which could be different between sqcc and adenocarcinoma.
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PMID:p53 immunohistochemical expression of Egyptian cervical carcinoma. 1060 22

Colorectal carcinoma is uncommon in Egypt, but a high proportion of cases occurs before age 40 years and in the rectum. We compared the molecular pathology of 59 representative Egyptian patients aged 10-72 to Western patients with sporadic, young-onset, or hereditary non-polyposis colorectal cancer syndrome (HNPCC)-associated carcinoma and found significant differences. Most Egyptian cancers were rectal (51%) and poorly differentiated (58%). High levels of microsatellite instability (MSI-H) were frequent (37%) and attributable in some cases (36%) to methylation of the promoter of the hMLH1 mismatch repair gene, but no MSI-H cancer had loss of hMSH2 mismatch repair gene product of the type seen with germline hMSH2 mutation in HNPCC. K-ras mutation was uncommon (11%). In subset analyses, high frequencies of MSI-H in rectal carcinomas (36%) and p53 gene product overexpression in MSI-H cancers (50%) were found. MSI-H and K-ras mutation in Egyptians under age 40 were unusual (17% and 0%, respectively), and schistosomiasis was associated with MSI and K-ras mutation. Cluster analysis identified 2 groups: predominantly young men with poorly differentiated mucinous and signet-ring cell colorectal carcinoma lacking K-ras mutation; older patients who had well- or moderately differentiated adenocarcinoma often with MSI-H, K-ras mutation and schistosomiasis. Our findings show that the molecular pathology of colorectal cancer in older as well as younger Egyptians has unique differences from Western patients, and schistosomiasis influences the molecular pathogenesis of some tumours.
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PMID:Contrasting molecular pathology of colorectal carcinoma in Egyptian and Western patients. 1159 77


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