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 accumulation of p53 protein in the nuclei of cancer cells is known to correlate well with the presence of mutations in the p53 gene. We therefore investigated the immunohistochemical reactivity of the anti-p53 antibody, PAb1801, in specimens taken from 149 cases of primary gastric cancer and processed by acetone fixation, in order to elucidate the incidence and clinicopathological significance of p53 alterations in gastric cancer. Thirty-four out of 99 (34%) advanced gastric cancers and 11 out of 50 (22%) early gastric cancers showed positive reactions in the nuclei. The nuclei of non-cancerous cells, including gastric glandular epithelial cells, however, were not stained. Histopathologically, a nuclear accumulation of p53 protein was seen frequently in papillary adenocarcinoma, well- to moderately-differentiated tubular adenocarcinoma and poorly-differentiated adenocarcinoma with solid nests or focal tubular structures (43/101, 43%), but was rarely seen in signet-ring cell carcinoma, mucinous adenocarcinoma or poorly-differentiated adenocarcinoma growing in a scattered manner (2/48, 4%). There was no correlation between stainability of p53 protein and clinicopathological features such as depth of tumor invasion, microscopic lymphatic invasion, microscopic venous invasion, nodal involvement and clinicopathological stage in papillary adenocarcinoma, well- to moderately-differentiated tubular adenocarcinoma and poorly-differentiated adenocarcinoma with solid nests or focal tubular structures. The results suggest papillary adenocarcinoma, well- to moderately-differentiated tubular adenocarcinoma and poorly-differentiated adenocarcinoma with solid nests or focal tubular structures to share a common carcinogenetic pathway in which mutation of the p53 gene has an important role to play at a relatively early stage. Additionally, we showed the applicability of immunohistochemical detection of p53 protein in endoscopic biopsy material routinely formalin-fixed. The current method may be of some help in routine practice in discriminating between normal, precancerous and cancer cells in the stomach.
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PMID:High incidence of nuclear accumulation of p53 protein in gastric cancer. 127 44

p53 was originally considered to be a nuclear oncogene, but several convergent lines of research have indicated that the wild-type gene functions as a tumor suppressor gene negatively regulating the cell cycle. Mutations in the p53 gene have been detected in many tumor types and seem to be the most common genetic alterations in human cancer. In this preliminary study, sera of 92 patients (pts) with breast disease were analyzed for the presence of the mutant p53 protein (mp53) with a selective immunoenzyme assay employing a monoclonal antibody (PAb 240) specific for the majority of mammalian m p53 but not for the wild-type protein. Of the 10 patients with benign breast disease, only two (20%) showed detectable m p53 levels in the serum. In the breast cancer group, sera from 7 of the 30 pts (23%) without lymph node involvement were positive for m p53, as were 7 out of the 45 pts (15%) with metastatic lymph nodes and 1 out of the 7 pts (14%) with disseminated disease. The specificity of m p53 assay evaluated in 20 healthy controls was 100%. These preliminary results showed that serum positivity for m p53 is not related to breast disease extension. Further studies to assess the utility of m p53 as a possible prognosis factor in breast cancer are currently in progress.
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PMID:The p53 tumor suppressor gene. A preliminary clinical study in breast cancer patients. 128 28

The results of the present study of the p53 antioncogene in a broad panel of human cell lines (n = 32) and biopsy specimens (n = 435) from both normal and tumour tissues can be summarized as follows: 1. Cells in primary cultures from normal tissues express very low levels of the p53 protein while strong nuclear accumulation of p53 can be seen in all SV 40 transformed human cell lines and the vast majority of tumour--derived cell lines studied. 2. Similarly, in human tissues strong nuclear p53 expression is found in high proportion of malignancies of various histogenesis, in contrast to benign lesions, nonmalignant tissues surrounding malignant tumours and normal tissues in which the p53 protein levels remain below the limits detectable by common immunohistochemical methods. 3. Sequence analysis of p53 mRNA amplified by polymerase chain reaction (PCR) revealed point mutations in the central region of the p53 gene in several cancer cell lines. Furthermore, very good correlation was found between the presence of such mutations and accumulation of the mutated p53 protein. This study confirms and extends our current view of p53 as the gene most frequently altered in human cancer and suggests that simple immunohistochemical methods can be used to screen for aberrations of this antioncogene.
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PMID:[Aberrations of the p53 antioncogene in malignant tumors]. 128 75

Nasopharyngeal carcinoma (NPC) is the third most common cancer in the southern provinces of China, but a rare cancer in other parts of the world. Epidemiological studies suggested a multifactorial etiology of NPC involving infection of Epstein Barr virus (EBV), genetic predisposition, environmental factors, such as consumption of salted fish, and other unknown factors. p53 mutation is a common event in many forms of human cancers but its possible involvement in the pathogenesis of NPC has not been examined. The presence of p53 mutation in NPC is studied by the sensitive PCR-SSCP analysis and direct DNA sequencing method. The frequent sites of p53 mutation (exons 4 to 8) reported in other human tumors were studied. Thirty-eight biopsied tumors of NPC and 4 NPC cell lines were examined for the presence of p53 mutation. No mutation of p53 resulting in change in amino acid sequence of the encoded p53 protein was identified in any of the biopsies tumors. RFLP studies of the biopsied materials of NPC also revealed no loss of heterozygosity at chromosome region 17p13 in 15 out of 15 informative cases, which further supports the conclusion that p53 mutation is an infrequent event in NPC. Apparently, p53 mutation has no significant role in the pathogenesis of this special group of human cancers. However, p53 mutation is frequently observed in cell lines derived from the primary NPC tumors. All the three NPC cell lines examined carry a missense p53 mutation, suggesting that mutation of the p53 gene may confer growth advantage to the tumor cells to become established in culture.
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PMID:p53 mutation in human nasopharyngeal carcinomas. 129 43

The p53 tumour suppressor gene is intensively studied because mutations in this gene are the most common genetic alteration so far identified in human cancer. Considerable emphasis has thus been placed on characterizing the biological differences between mutant and wild-type p53 protein. This has led to the realization that in cultured cells, mutant p53 behaves like an oncogene, whereas wild-type p53 is a tumor suppressor gene. The p53 protein is also a target for the tumour virus oncogene products SV40 large T, adenovirus E1B, and human papillomavirus type 16 E6, which are all capable of forming complexes to the p53 protein. Although p53 represents an extremely important cellular regulatory molecule which is well conserved, there exists two allelic variants of wild-type human p53 that differ both in primary and confirmational structure. One variant contains an arginine at amino acid 72 (p53Arg), whereas the other form contains a proline at this residue (p53Pro). The possible implications for more than one allelic variant of wild-type human p53 in the general population is unknown. The present study was undertaken to compare some of the biological features of the different wild-type p53 variants. We present data demonstrating that there was a post-transcriptional selection against accumulation of both variants of wild-type human p53 in 3T3-A31 cells, arguing that both forms are proliferation inhibitory in these cells. Both variants of human p53 were stabilized by SV40 large T, but did not displace mouse p53 from SV40 large T. Neither allelic variant of human p53 was able to reduce significantly SV40-mediated anchorage-independent growth of 3T3-A31 cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular analysis of different allelic variants of wild-type human p53. 129 28

p53 is a tumor suppressor gene that is mutated in diverse tumor types. Here we report the frequencies of common polymorphic variants at codon 72 of the p53 gene in germline DNA of lung cancer cases and controls as determined by a polymerase chain reaction strategy. The observed allelic distribution was found to be significantly different between African-Americans and Caucasians in this U.S. population. The frequency of polymorphic variants was similar in lung cancer cases and controls after adjustment for race. However, among lung cancer patients the proline variant at codon 72 was in excess in adenocarcinoma patients by comparison with other histologies.
Cancer Epidemiol Biomarkers Prev
PMID:Allelic frequency of a p53 polymorphism in human lung cancer. 130 61

Molecular abnormalities of the p53 gene in chromosome 17p may be among the most commonly observed in human cancer. Their role in gastric carcinogenesis is suggested by their frequent detection in invasive adenocarcinomas. To investigate the chronology with which these abnormalities appear in the gastric carcinogenesis process, the expression of p53 proteins was investigated in late stages of the process, namely dysplasia, and in superficial carcinomas. A polyclonal antibody, CM-1, against both wild-type and mutant proteins was applied to paraffin-embedded biopsy and gastrectomy specimens previously fixed in buffered formalin. Positive nuclear stain was obtained in 36.4% of 33 cases of gastric epithelial dysplasia, corresponding to 19% of mild, 27.3% of moderate, and 64.3% of severe dysplasias. Eight of 13 (61.5%) invasive carcinomas showed positive stain. The data indicate an increased incidence of p53 abnormalities in the late stages of gastric carcinogenesis.
Cancer Epidemiol Biomarkers Prev
PMID:Immunohistochemical evidence of p53 overexpression in gastric epithelial dysplasia. 130 67

The etiology of cancer is a complex interplay of various factors, including genetic alterations. Multiple studies have been carried out to identify and characterize mutations that frequently occur during tumorigenesis. In human breast cancer, amplification of proto-oncogenes (c-myc, c-erbB-2/neu) and chromosome 11q13, mutation of p53 and loss of heterozygosity (chromosomes 1, 3p, 6q, 7q, 11p, 13q, 16q, 17, 18q and 22q) represent the major types of genetic abnormalities that have been frequently observed in tumor DNAs. The genetic deletions and mutations could inactivate tumor-suppressor genes. In some studies, specific alterations have been associated with some clinical parameters. Recently, linkage analyses, on large families with a predisposition to breast cancer, have been performed to map putative breast cancer susceptibility genes. The survey of high risk patients should be organised to make an earlier diagnosis.
Bull Cancer 1992
PMID:[Molecular analysis of breast cancers: recent developments]. 130 32

There are few cytogenetic studies of early (non-invasive) bladder cancer, particularly in situ carcinoma, due to technical difficulties in examining such lesions. The best approach is to extrapolate from chromosomal changes in more advanced cancers. Although no specific chromosomal changes have been established in either early or fully developed bladder cancers, certain recurrent anomalies have been encountered. Anomalies such as +1, +7, -9, 5q- or i(5p), 11p- and -Y appear to constitute part of the multistep carcinogenetic process by which clinically and pathologically recognizable bladder cancers develop. Since loss of part or all of chromosome 9 (-9) is a common and early cytogenetic event in bladder cancer, the detection of -9 in bladder washings or urine by fluorescence in situ hybridization (FISH) may be a promising test for early or recurrent bladder cancer. Although less frequent than -9, trisomy 7 (+7) is common enough to serve a similar purpose. In contrast, loss of the Y chromosome may indicate an advanced stage of bladder cancer. Thus, FISH studies utilizing probes for chromosomes 7, 9, and Y should yield cogent information to identify early bladder cancer. Cytogenetic (including FISH) studies combined with certain molecular approaches (e.g., p53 mutations detected immunochemically) may not only serve to differentiate early cancer from benign tumors or conditions, but may also help establish cancer stage. This would supply data of considerable usefulness to the clinician and pathologist.
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PMID:Chromosome changes in early bladder neoplasms. 130 93

Evolutionary aspects of human cancer can be dealt with at two levels--on the one hand long-term evolution involving hereditary effects between generations; and on the other hand evolutionary processes operating within the organisms between tissues, cells and cell constituents, which also comprise genetic alterations, selection and adaptation. These two levels of evolution can be designated as phylogenetic and ontogenetic evolution, respectively. Concerning phylogenetic evolution there must have been a strong selection against neoplastic diseases occurring at reproductive age and a variety of protective mechanisms against carcinogenic agents have been developed. Cancer is therefore primarily a disease of old age, which does not constitute a significant risk in natural populations for the simple reason that the life length is too short. The development of an individual comprises selection forces between cells and tissues, which are particularly striking for the multistage development of tumours. The accumulation of several genetic alterations in the same cells, as illustrated by the analysis of colorectal tumours, must require a pronounced clonal expansion between each event. Such selective growth effect has recently been demonstrated for the tumour suppressor gene p53 in brain tumours. Cancer often implies a break down of between balanced systems antagonistic forces, such as oncogenes and suppressors of oncogenes. Examples of this are provided by the genetic regulation of metastasis, involving metalloproteinase as well as the inhibitor of metalloproteinase. The immortalization of cells by transformation points to the fact that programmed cell death and the balance between suicide genes and suppressors of such suicide genes is affected.
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PMID:Evolutionary aspects of human cancer. 130 36


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