Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A tumour suppressor function for p53 is indicated in human lung cancer and in carcinoma of the colorectum. Loss of suppressor function, by mutation of the p53 gene, is associated with activation of p53 as an oncogene. The suppressor (wild type) and oncogenic (mutant) forms of the murine p53 protein are distinguishable at the molecular level by reactivity with anti-p53 monoclonal antibodies. For example, activated mutant p53 fails to react with PAb246 (p53-246 degrees). We now demonstrate that wild type p53 mRNA can be expressed either as p53-246+ or p53-246 degrees. We propose that p53-246 degrees may represent an allosteric variant of wild type p53 compatible with positive growth control. Thus, for wild type p53 the variants p53-246+ and p53-246 degrees may reflect suppressor and activator functions of p53 in the normal control of cell proliferation. For human p53 we present evidence that the epitope recognised by PAb1620 is analogous to that for PAb246 on murine p53. Thus the epitope for PAb1620 may prove to be of use as a marker for wild type human p53 with anti-oncogenic function.
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PMID:Evidence for allosteric variants of wild-type p53, a tumour suppressor protein. 213 77

This investigation of oral squamous carcinoma in five individuals revealed that four of the patients were constitutionally heterozygous at the c-Ha-ras-1 locus and that the tumour from one patient had lost that heterozygosity. The loss of c-Ha-ras-1 alleles provides a useful marker for detecting deletions of genetic material located on the short arm of chromosome 11 (11p) and has been found in association with a number of malignant tumours but has not been previously described in carcinoma of the head and neck. The repeated association of 11p deletions with malignancies has led to the postulation of a recessive cancer gene or tumour suppressor gene at this location involved in carcinogenesis and tumour progression. This study indicates that such a mechanism may contribute to the development of oral squamous carcinoma.
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PMID:Loss of Harvey ras heterozygosity in oral squamous carcinoma. 256 83

Mutations in a human homologue of the yeast DNA mismatch repair gene MSH2 (equivalent to bacterial MutS) cause the condition hereditary non-polyposis colorectal cancer (HNPCC). Cancers in HNPCC originate within benign neoplastic polyps termed adenomas. Adenomas are clonal and each may serve as a marker of a single initiating mutation. The progression of adenomas is marked by increasing size, dysplasia and villosity. These characteristics can be taken as the morphological counterparts of the stepwise accumulation of mutations implicating oncogenes and tumour suppressor genes. The aim of this study was to link the morphogenesis of hereditary colorectal cancer with recent insights into the role of DNA mismatch repair genes. The frequency and anatomical distribution of adenomas in at-risk members of HNPCC families was the same as in an autopsy population. This suggests that the HNPCC gene does not initiate the process of neoplastic transformation. On the other hand, adenomas in at-risk members of HNPCC families were more likely to show villosity (p < 0.001), high grade dysplasia (p = 0.002) and probably increased size (p = 0.15). These findings are consistent with the observation that the HNPCC gene causes DNA replication errors to develop and accumulate within neoplastic but not normal tissues. The effect of the HNPCC gene is to accelerate the progression of adenoma to carcinoma, but not to initiate adenoma development.
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PMID:Hereditary non-polyposis colorectal cancer--morphologies, genes and mutations. 752 76

The present study analyses tumour samples from 41 patients with squamous cell carcinoma of the head and neck (SCCHN) using the polymerase chain reaction (PCR) to detect genetic alterations on chromosome 18. Microsatellite markers were used to examine each sample for loss of heterozygosity (LOH) and microsatellite instability. Genetic alterations were most commonly noted on the long arm of chromosome 18 (18q). LOH/microsatellite instability occurred on 18q in 20/41 (49%) of patients. The highest single incidence of LOH was found at 18q21.1-21.3 using the microsatellite marker D18S35. LOH occurred in 10/30 (33%) informative cases while LOH/microsatellite instability occurred in 13/30 (43%) informative cases using this marker. Interestingly the tumour suppressor gene known as the 'deleted in colonic carcinoma' (DCC) gene is located in this region at 18q21.3 but is not commonly lost. This suggests that the marker D18S35 is mapping close to a second as yet unidentified tumour suppressor gene in this area.
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PMID:Chromosome 18: a possible site for a tumour suppressor gene deletion in squamous cell carcinoma of the head and neck. 755 43

We report a clinical case of a double primitive tumour (right kidney clear cell carcinoma and gastric carcinoma) in two brothers. There is no history of cancer in the parents. Both patients were previously affected by gastric ulcer. No report of association between the two neoplasms was found in literature. The age of the patients (61 and 70 years) and the singleness of the kidney tumour seem to exclude the case of a familial kidney cancer. The neoplastic transformation of the gastric ulcer is instead a quite frequent report with an incidence of about 1%. Alterations of oncogenes or tumour suppressor genes shared from both neoplasm are at present still unknown. Nevertheless molecular analysis of patients' neoplastic genome could point out typical chromosome translocations/deletions or gene mutations.
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PMID:[Appearance in 2 brothers of double primary neoplasms: right renal carcinoma and gastric adenocarcinoma]. 757 Feb 61

The product of the retinoblastoma susceptibility tumour suppressor gene, pRb, is a negative regulator of cell proliferation. In order to investigate the interaction between pRb and the cell cycle machinery in more detail, a functional Rb gene was reintroduced into the Rb-deficient human mammary carcinoma cell line Bt549. Since constitutive high level expression of Rb turned out to be difficult to maintain, the tetracycline-dependent gene expression system was used. A number of clones was generated which all showed low level expression in the noninduced state. Considerable induction rates were obtained. The low level of noninduced Rb expression was sufficient to induce the expression of cyclin D1 the level of which was not further increased by upregulation of Rb expression. Concomittantly, an increase in cell doubling time was observed due to retardation of the cell cycle in the G1-phase. The data suggest that limiting amounts of cyclin D1 determine, at least partly, the extent of growth-repressing properties of pRb. The inducible system allows for maintenance of Rb-reconstituted cells at a low level of expression and for their use in the investigation of downstream functions of pRb.
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PMID:Regulated expression of the retinoblastoma susceptibility gene in mammary carcinoma cells restores cyclin D1 expression and G1-phase control. 757 42

The occurrence of the p 53 gene mutation in breast carcinoma tumour cells, leads to the accumulation of mutant p 53 protein types, whose consequence is the loss of the negative regulation normally exercised by the p 53 gene, which is considered to act as a tumour suppressor. It is possible to demonstrate the presence of mutant p 53 protein types in tumour cell nuclei by applying immunohistochemical procedures to paraffin sections (Clon DO 1, Dianova). We tested 482 primary breast carcinomas for the presence of these proteins, and positive immunohistochemical findings for mutant p 53 proteins were recorded in 21.6% of the cases. In another 14.3% of these breast carcinomas, less than 10% of the tumour cells exhibited positive staining. In the other 64.1% of cases, the immunohistochemical findings for p 53 proteins were entirely negative. Independent of the immunohistochemical staining results, we performed a retrospective analysis of the disease course of this group of primary breast carcinomas: it emerged, that p-53-positive breast carcinomas had a significantly less favourable prognosis as compared to primary tumours, which were negative or weakly positive for this protein group. The accumulation of p 53 proteins in tumour cell nuclei is correlated with negative oestrogen- and progesterone-receptor status, as well as with the degree of proliferation exhibited by the breast carcinoma. Such accumulation is, in contrast, unaffected by the tumour stage, its histological grading, menopausal status, and the overexpression of c-erb B2.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Immunohistochemical detection and prognostic significance of p53 in the primary tumor of breast carcinoma patients]. 760 81

The concept of field cancerisation assumes that in head and neck cancer patients (HNCP) with multiple malignancies the second primary cancers may arise independently from the entire upper aerodigestive tract as a consequence of massive exposure to common carcinogens. Since mutations and/or overexpression of the p53 tumour suppressor gene represent a genetic alteration frequently occurring in HNCP, we analysed immunocytochemically p53 oncoprotein expression in first primary, second primary cancers and in macroscopically uninvolved normal epithelium from different sites of the upper aerodigestive tract from 12 HNCP with multiple malignancies, in comparison with p53 expression in biopsy specimens of the upper aerodigestive tract from 5 non-neoplastic heavy smokers, as controls. In patients with multiple malignancies 6 cases (50%) showed positive staining of both first and second primaries, whereas 3 (25%) had positive labelling of first primary cancer but not of the subsequent second primary, 2 (17%) patients showed p53 expression only in the second primary cancer, and finally only 1 patient (8%) showed no p53 immunoreactivity in both first and second primary tumours. Moreover, 10 out of 12 (83%) HNCP with multiple cancers showed p53-positive staining in the normal epithelium from different sites of the upper aerodigestive tract, also at a significant distance from the site of first and second primary malignancies. contrast, sporadic p53 immunostaining was observed only in three out of 35 (8.5%) specimens from non-neoplastic controls. In addition, in 4 HNCP with multiple tumours the histological examination of apparently normal epithelium from the upper aerodigestive tract revealed signs of moderate or severe dysplasia, and in 1 case an in situ carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:p53 expression: a potential biomarker for risk of multiple primary malignancies in the upper aerodigestive tract. 762 89

Loss of heterozygosity (LOH) at the deleted in colorectal carcinoma gene (DCC), a tumour suppressor gene that encodes a protein with high homology to the neural cell adhesion molecule, was investigated in 42 surgical specimens of primary breast carcinoma. LOH was analysed in breast carcinoma by amplifying the DNA, spanning a variable number of tandem repeats site and a restriction fragment length polymorphism site within DCC, using the polymerase chain reaction (PCR). Cell sorting was used to enrich carcinoma cells. The expression of the DCC gene was also investigated using a reverse transcription-PCR method followed by Southern blot hybridization. LOH at the DCC locus was detected in 15 (51.7%) of 29 informative cases and 10 of 13 cases having DCC-LOH showed distinct reduction or loss of DCC expression. The DCC-LOH was closely associated with certain histological phenotypes: DCC-LOH was more frequent in scirrhous carcinomas than in solid-tubular ones (P < 0.05), and was also more frequent in carcinomas with infiltration into fat tissue over the mammary gland than in those without infiltration (P < 0.05). DCC-LOH was detected in invasive lobular carcinomas (2/2), but in none of the noninvasive ductal carcinomas (0/2). These observations suggest that malignant histological phenotypes are associated with DCC-LOH.
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PMID:Frequent loss of heterozygosity at the deleted in colorectal carcinoma gene locus and its association with histologic phenotypes in breast carcinoma. 763 54

Combined multi-point linkage analysis in seven Dutch families with FAMMM syndrome confirmed the location of a melanoma susceptibility (MLM) gene in the 9p21 area. The occurrence of a shared high-risk haplotype in six of the families strongly suggests a founder effect in the Leiden region. No indication for locus heterogeneity was observed. Recently, the CDKN2 (p16) gene, an important regulator of the cell cycle, was isolated from the 9p21 region. A 19-bp germline deletion in the CDKN2 gene was detected in the high-risk haplotype, suggesting CDKN2 to be identical to MLM. Loss of heterozygosity studies in melanoma and pancreatic carcinoma from gene carriers strongly support the view that CDKN2 is a general tumour suppressor gene predisposing not only to melanoma but also to other malignancies. Interestingly, the occurrence of apparent clinical FAMMM cases with melanoma but without the high-risk deletion haplotype suggests the necessity of additional (naevus) genes to explain the complete FAMMM phenotype.
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PMID:CDKN2 explains part of the clinical phenotype in Dutch familial atypical multiple-mole melanoma (FAMMM) syndrome families. 764 May 18


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