UNIPROT:P04637 - FACTA Search

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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

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

Using monoclonal antibodies, we have identified a series of tumor-associated antigens selectively expressed on tumor subtypes with distinct clinical behaviours. The mucinous antigen M344 and the gp200 surface antigen 19A211 are preferentially expressed on papillary superficial tumors and carcinoma in situ lesions of the bladder. The combination of these two antigenic markers in immunocytology and flow cytometry studies of exfoliated cells has improved the sensitivity of detection for bladder tumors. Moreover, the detection of M344- and 19A211-positive exfoliated cells from previously treated but currently tumor-free patients appears to be predictive of tumor recurrence on follow-up. These results, as well as results of bladder mapping studies in tumor patients, suggest that these antigenic changes occur in a premalignant stage and may provide tools to monitor the efficacy of chemopreventive measures. Other markers, such as the surface antigen T138 and the soluble molecules autocrine motility factor (AMF) and tumor collagenase stimulating factor (TCSF), are produced by primary or recurrent tumors with a higher metastatic potential. They may be useful in identifying high risk patients for distant failure. The highly restricted antigen 19A211 is also expressed on cervix condylomas and carcinoma. This observation led us to investigate a possible viral etiology of some bladder cancers. Using PCR techniques, we detected the presence of human papillomavirus (HPV) 16 DNA sequences in a significant proportion of bladder tumors. HPV positivity was inversely correlated with the presence of p53 mutations in exons 5-9 of the same tumors as measured by PCR-SSCP technique. This combination of markers may provide a basis for chemoprevention strategies targeted to distinct etiological events.
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PMID:Strategies of chemoprevention based on antigenic and molecular markers of early and premalignant lesions of the bladder. 130 95

In this study, structural changes of the p53 gene in primary specimens of human colorectal carcinomas were analyzed by polymerase chain reaction mediated-DNA sequencing method. Point mutations of p53 gene, including an intronic mutation case, were detected in 8 of 14 carcinomas (57%). Point mutations of the gene were also observed in 2 of 2 adenomas, suggesting that mutations occur prior to the carcinoma stage. These results support that p53 gene plays an important role in the development of colorectal cancer. The frequency of Ki-ras oncogene mutations was also studied by polymerase chain reaction-single strand conformation polymorphism analysis (PCR-SSCP). This resulted in the rate of 42% (10/24), a quite similar value obtained by other methods. As PCR-SSCP analysis is a convenient method to detect point mutation, we have now examined 24 colorectal cancers for the p53 gene by this method, and detected the mutations. Furthermore, expression of the DCC gene, a candidate of tumor suppressor gene involved in colorectal carcinogenesis, was examined by reverse transcriptase-mediated PCR (RT-PCR) assay, resulting in significant reduction on the DCC expression in 8 of 14 carcinoma cases (57%).
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PMID:Mutations of the p53 gene and other genes involving in human colorectal carcinogenesis. 130 99

Aflatoxin B1 has been suggested as a causative agent for a G to T mutation at codon 249 in the p53 gene in human hepatocellular carcinomas from southern Africa and Qidong in China. To test this hypothesis, nine tumors induced by aflatoxin B1 in nonhuman primates were analyzed for mutations in the p53 gene. These included four hepatocellular carcinomas, two cholangiocarcinomas, a spindle cell carcinoma of the bile duct, a hemangioendothelial sarcoma of the liver, and an osteogenic sarcoma of the tibia. None of the tumors showed changes at the third position of codon 249 by cleavage analysis of the HaeIII enzyme site at codon 249. A point mutation was identified in one hepatocellular carcinoma at the second position of codon 175 (G to T transversion) by sequencing analysis of the four conserved domains (II to V) in the p53 gene. These data suggest that mutations in the p53 gene are not necessary in aflatoxin B1 induced hepatocarcinogenesis in nonhuman primates. The occurrence of mutation in codon 249 of the p53 gene in selective samples of human hepatocellular cancers may indicate involvement of environmental carcinogens other than aflatoxin B1 or that hepatitis B virus-related hepatitis is a prerequisite for aflatoxin B1 induction of G to T transversion in codon 249.
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PMID:Low frequency of p53 gene mutation in tumors induced by aflatoxin B1 in nonhuman primates. 131 Jun 37

Mutation and loss of heterozygosity (LOH) in the p53 gene were analyzed in 274 colorectal tumors of 4 histopathological grades. Among 160 tumors from 40 familial adenomatous polyposis patients, none of 58 adenomas with moderate dysplasia had p53 mutations, whereas 8% (3 of 37) of severe adenomas, 15% (6 of 40) of intramucosal carcinomas, and 40% (10 of 25) of invasive carcinomas had p53 mutations. Only 3% (1 of 33) of severe adenomas showed both mutation and LOH, while 25% (6 of 24) of intramucosal carcinomas and 40% (10 of 25) of invasive carcinomas had both mutation and LOH. All intramucosal and invasive carcinomas that had mutations lost the other allele of the p53 gene. In 114 tumors from 86 non-familial adenomatous polyposis patients, similar results were obtained; no adenoma showed both mutation and LOH, but both alterations occurred in intramucosal and invasive carcinoma. As regards specificity in 56 mutations detected in the present study, the frequently affected codons were codons 175, 238, 245, 248, 273, and 282, 4 of these amino acids being arginine, and 72% (39 of 54) of all mutations were GC to AT transition. Although expression into p53 polyadenylated RNA was high in every invasive carcinoma irrespective of the presence of mutation or LOH, there was a correlation between mutation and protein level; immunostaining of p53 protein was negative in almost all adenomas, but it was positive in 86% of invasive carcinomas exhibiting p53 mutation. These data suggest that genetic changes on both alleles of the p53 gene through mutation and LOH, which result in abnormal protein accumulation, are involved in the conversion of adenoma to early carcinoma. Also, carcinoma cells with p53 mutations existing within adenoma tissues are detectable by immunostaining, even in formalin-fixed, paraffin-embedded specimens.
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PMID:Genetic changes of both p53 alleles associated with the conversion from colorectal adenoma to early carcinoma in familial adenomatous polyposis and non-familial adenomatous polyposis patients. 131 35

The HPVs associated with anogenital cancers encode two oncoproteins, E6 and E7. Both E6 and E7 can form specific complexes with tumour suppressor gene products. The E7 protein binds to the retinoblastoma tumour suppressor gene product pRB, with a preference for the underphosphorylated, "active" form of pRB. The E7 proteins derived from the "high risk" HPVs bind to pRB with a higher affinity than the E7 proteins from the "low risk" HPVs. The "high risk" HPV E6 proteins can associate with the p53 tumour suppressor protein. This interaction promotes the degradation of p53 in vitro, which presumably accounts for the very low levels of p53 in cervical carcinoma cell lines. The functional inactivation of pRB and p53 by the HPV oncoproteins E7 and E6, respectively, are likely to be important steps in cervical carcinogenesis, since mutations in the RB and p53 genes were detected in HPV negative but not HPV positive cervical carcinoma cell lines. Cytogenetic studies strongly suggest, however, that additional chromosomal changes may be necessary for carcinogenic progression of HPV induced anogenital lesions.
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PMID:Interactions of HPV E6 and E7 oncoproteins with tumour suppressor gene products. 132 42

Low grade breast cancers i.e. mucinous (17 cases--3.2%), tubular (7 cases--1.3%) and invasive cribriform carcinomas (3 cases--0.5%) have been identified within a series of 524 breast cancers only by histotyping in hematoxylin-eosin stained sections: the reactivities of immunohistochemical prognosticators as estrogen/progesterone receptors (ER, PgR), growth fraction (GF: Ki67), p53 and c-erbB-2 oncoproteins are in agreement with clinical behaviours. Invasive papillary carcinomas (9 cases--1.6%) are not to be considered low grade carcinomas. Intermediate grade cancers are also determined by histotyping. Medullary carcinoma (13 cases--3.4%) has a paradoxical behaviour displaying a favourable clinical prognosis together with high grading and GF, absence of ER, PgR, high p53 and c-erbB-2 values, as compared with invasive ductal carcinomas: an extensive tissue immune response as suggested by a heavy lymphocyte infiltration may explain this behaviour. Invasive lobular carcinoma (62--11.6%) shows an intermediate immunohistochemical pattern, paralleling an intermediate prognosis, when compared with low and high grade carcinomas: ER, PgR and GF positivities are nearly the same as in ductal carcinomas whereas grading, p53 and c-erbB-2 are less expressed. These data are confirmed both for lobular carcinomas as a whole and for all variants of this kind of tumors. Invasive ductal carcinomas (413 cases--79%) may be stratified on three prognostic classes corresponding to histological grading (G1, G2, G3). Significant relationships of grading with all the immunohistochemical prognosticators studied has been observed. It may be concluded that grading is a parameter of paramount importance in this group of tumors.
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PMID:Low, intermediate and high grade breast carcinomas as determined by histotyping, immunohistochemical prognosticators and histological grading. 132 96

Little is known regarding the molecular genetic events in head and neck carcinoma. Epidemiological evidence suggests that both alcohol and tobacco use are related to the development of these neoplasms, and viral infections have also been postulated to play a role in some tumors. Loss of p53 tumor suppressor gene function has been found in many malignancies and can occur through either gene mutation or by interaction with the E6 protein of oncogenic human papilloma viruses (HPV). Because the mucosal surfaces of the head and neck are exposed to mutagens and HPVs, we studied DNA derived from 30 stage I-IV squamous cell carcinomas of the head and neck (9 primary tumors and 21 early passage cell lines) for p53 gene mutations as well as for the presence of oncogenic HPV DNA. Exons 2 through 11 of the p53 gene were examined using single strand conformation polymorphism analysis followed by direct genomic sequencing of all variants. HPV detection was done using polymerase chain reaction amplification with HPV E6 region type specific primers as well as L1 region degenerate ("consensus") primers; HPV type was determined by restriction fragment length polymorphism analysis of the amplified fragment as well as by Southern blotting of genomic DNA. Sixteen of 30 tumors (53%) had p53 mutations and oncogenic HPV DNA was detected in 3 of 30 (10%) tumors, none of which had p53 mutations. The p53 mutational spectrum observed was characterized by equal frequencies of transversions (6 of 16), transitions (5 of 16), and deletions (5 of 16). This distribution of mutations differs from the spectrum of p53 mutation reported in esophageal (P = 0.05) and lung (P = 0.02) cancers, two other tobacco associated neoplasms. A previously undescribed clustering of 3 mutations at codon 205 was also observed. A trend toward a shorter time to tumor recurrence after treatment was noted for those patients with tumors exhibiting p53 gene mutations, and no relationship between p53 mutations and tumor stage or node status was noted. Alteration in p53 gene function appears common in head and neck cancer, and the mutational spectrum observed may reflect the role of different mutagens or mutagenic processes than those responsible for the p53 mutations in lung and esophageal neoplasms.
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PMID:Occurrence of p53 gene deletions and human papilloma virus infection in human head and neck cancer. 132 97

A previous report using cervical carcinoma cell lines suggests that the inactivation of two tumor suppressor gene products, p53 and pRB, either by complex formation with the E6 and E7 proteins of oncogenic human papillomaviruses (HPVs) or by mutation, may be an important step in cervical carcinogenesis (M. Scheffner et al., Proc. Natl. Acad. Sci. USA, 88: 5523-5527, 1991). The present study was designed to clarify the association between p53 inactivation and infection with oncogenic HPVs in primary carcinomas of human uterine cervix. We examined 36 primary cervical carcinomas for the presence of HPV DNAs by Southern blot analysis with probes specific for HPV-16, -18, -31, -33, -52, -56, and -58. HPV DNA sequences were detected in 19 of 36 tumors: 10 cases with HPV-16; 3 cases with -18; 3 cases with -58; 2 cases with -56; and one case with -52. The presence of HPV-16 and -18 in cervical carcinomas was further reexamined using polymerase chain reaction. HPV DNA sequences were detected in an additional 10 cases: 9 cases with -16 and one case with -18. The inactivation of the p53 gene by allelic loss or by point mutation was also examined. No allelic loss at the polymorphic site in codon 72 of the p53 gene was detected in any of 10 informative cases. Missense point mutations in the highly conserved regions of the p53 gene were demonstrable as single-stranded conformational polymorphisms of polymerase chain reaction-amplified DNA fragments and subsequently identified by direct DNA sequencing. Point mutations were detected in only two cases: one with an ATG----CTG transversion in codon 133 of exon 5, resulting in a Met----Leu substitution, and another with a CGG----TGG transition in codon 248 of exon 7, resulting in an Arg----Trp substitution. Both tumors with point mutations in p53 genes were among 10 tumors which contained a small copy number of HPV-16 DNA sequences (1 copy of HPV/10(1) to 10(5) cells) detectable by polymerase chain reaction amplification but not by Southern blot analysis of genomic DNAs derived from the tumors. None of 19 tumors with a large copy number of HPV DNA sequences detectable by Southern blot analysis (more than 1 copy of HPV/2 to 10 cells) nor any of 7 tumors with undetectable HPV DNA sequences contained p53 gene mutations in the regions examined.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Alterations of the p53 gene in human primary cervical carcinoma with and without human papillomavirus infection. 132 6

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