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Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human papillomaviruses (HPVs) appear to play a role in the etiology of the vast majority of virus-associated human malignancies. Studies of viral gene expression in carcinomas suggest the importance of two HPV encoded proteins, E6 and E7, in malignant development and these proteins have been shown to encode transforming and immortalising activities. The two proteins show some functional resemblance to the transforming proteins of other small DNA tumour viruses such as adenovirus and SV40. Recent evidence suggests that one important function of these virus-encoded proteins is binding the products of the cellular tumour suppressor genes RB and p53, revealing an exciting link between oncogenes and anti-oncogenes.
Semin Cancer Biol 1990 Dec
PMID:Human papillomavirus oncoproteins. 196 93

c-erbB-2 gene amplification and protein over-expression were investigated in 89 primary tumours and 24 metastases from Norwegian breast cancer patients. Amplification occurred in 22.5% of the primary tumours and 50% of the metastases. The amplification was negatively correlated to the oestrogen receptor (ER) content in both the primary tumours and the metastases. No significant differences between amplified and non-amplified tumours were observed with regard to node status, clinical stage, tumour size or menopausal status, although correlations of borderline significance were found between node status, clinical stage and high degree of gene amplification. All the amplified tumours were of the invasive ductal type. Follow-up data of patients observed for more than 1 year showed a significantly higher recurrence rate in the c-erbB-2 amplified group. Allele loss of chromosome 17p and of 7q was seen in 55% and 48% of the tumours respectively. No significant correlation was found between these losses and clinico-histological parameters. More than 50% of the tumours with a loss of 17q sequences had an amplification of c-erbB-2 which is located on 17q12-21, indicating that only one of the chromosomes may be involved in the amplification of the c-erbB-2. A trend towards a correlation between loss of 17q and high degree of amplification were found. No correlation was found between positive family history of breast cancer and c-erbB-2 gene amplification, nor loss of 17p or 17q sequences. Our data support the hypothesis that amplification correlates with aggressive tumour behaviour, and thus may be used as a prognostic factor in breast carcinomas. The allele losses on 17p and 17q points to tumour suppressor gene or genes on this chromosome, although not as predisposing genes in families.
Br J Cancer 1990 Oct
PMID:Amplification and protein over-expression of the neu/HER-2/c-erbB-2 protooncogene in human breast carcinomas: relationship to loss of gene sequences on chromosome 17, family history and prognosis. 197 66

We have used 14 DNA probes, which detect 19 different restriction enzyme length polymorphisms, to search for heterozygosity on chromosome 3 in five cell lines isolated from patients with small cell lung carcinoma. The cell lines on karyotype analysis did not show the deletion in chromosome 3 characteristic of this disease. Our objective was to determine if allelic loss had occurred by some chromosomal mechanism other than deletion. Two of the cell lines are consistent with allelic loss having occurred by whole chromosome loss and reduplication. The third may have lost only the short arm due to i(3q) formation. The fourth cell line has an i(3q) chromosome, together with a translocation product involving the distal portion of the short arm of chromosome 3. Lack of evidence of heterozygosity for this distal portion of 3p suggests that a copy of the 3p homologue is involved in the translocation and therefore does not explain allelic loss of of the other homologue. The fifth, while also likely to have lost one chromosome homologue, has a submicroscopic deletion on all chromosome 3s, only detectable by RFLP analysis. Such homozygous deletions have recently proved useful in the isolation of tumour suppressor genes.
Genes Chromosomes Cancer 1990 Sep
PMID:A submicroscopic homozygous deletion at the D3S3 locus in a cell line isolated from a small cell lung carcinoma. 198 39

The technique of somatic cell hybridization and the concept of tumour suppressor genes share a common history. Somatic cell hybrids between mammalian tumour cells and their normal cellular counterparts invariably are non-tumorigenic, establishing the recessive genetic nature of tumorigenicity. The development of cytogenetics and microcell hybridization has provided methods for localization of the tumour suppressor genes to specific chromosomal regions. Continuing studies of this type will facilitate the isolation of these genes by molecular methods including differential cDNA screening and 'reverse genetics'.
Cancer Surv 1990
PMID:Genetic behaviour of tumorigenicity in human cancer. 198 9

Recent circumstantial evidence has implicated Insulin-like growth factor II in the genesis of several tumour types, notably developmental tumours (Scott et al., 1985; Schofield & Tate, 1987; Wilkins et al., 1989). This type of tumour, thought to originate during the defective differentiation of organ precursors (Miereau et al., 1987), often expresses greatly elevated levels of mRNA for IGF-II, a known mitogen for these cells and abundantly expressed in their presumed normal counterparts (Scott et al., 1985; Schofield & Tate, 1987; Gray et al., 1987). It has been proposed that continued, inappropriate expression of this gene drives tumour growth by an autocrine mechanism. In order to examine the potential role of IGF-II in the growth of tumour cells an IGF-II cDNA was introduced into a retroviral expression vector, and used to infect a cloned fibroblast cell line. Expression of IGF-II conferred a degree of serum independence of growth in cell culture, however, when cells were injected into nude mice as subcutaneous grafts, clones expressing IGF-II from the retrovirus were found to have a greatly increased (five fold) latency of sarcoma formation. After a prolonged lag all cell lines eventually gave rise to tumours in which the introduced IGF-II genes had either been lost or inactivated, suggesting that in this system IGF-II acts as a tumour suppressor gene.
Br J Cancer 1991 May
PMID:Tumour suppression associated with expression of human insulin-like growth factor II. 203 93

Genetic and molecular analyses of Drosophila have shown that tumorigenesis may arise from inactivation of single genes controlling cell growth and differentiation. Recessive mutations in a series of genes interrupt the differentiation of primordial cells and result in overgrowth, producing either hyperplasia or neoplasia. In mutant animals tumours form in either the optic centres of the larval brain, the imaginal discs or the haemopoietic organs. In Drosophila 17 genetic loci giving rise to neoplasia and six loci producing hyperplasia have been identified. The lethal(2)giant larvae gene constitutes the prototype of these genes. Its molecular cloning and analysis have demonstrated that the tumor phenotype results from a lack of gene function. Furthermore, tumour prevention was achieved by introducing a normal copy of l(2)gl into the genome of l(2)gl- deficient animals, showing that the l(2)gl gene behaves as a tumour suppressor or anti-oncogene. Melanomas of genetic origin develop in interspecies hybrids of the fish Xiphophorus. The melanoma appears when a sex linked chromosomal gene (Tu) is present among the progeny animals lacking an autosomal locus Differentiation, which acts as a tumour suppressor gene. A sequence homologous to the erb-B gene can be associated to the sex chromosomal Tu locus. This gene encodes a receptor tyrosine kinase related to the EGF-receptor, and its activation and overexpression are thought to play a critical part in melanoma formation.
Cancer Surv 1990
PMID:The fruit fly Drosophila and the fish Xiphophorus as model systems for cancer studies. 210 23

The goal of genetic analysis of malignant melanoma is to identify genes involved in the transformation of melanocytes and melanoma tumour progression. Three basic approaches have been used to analyze tumour progression in melanoma, and these include: (1) performing genetic linkage analysis on familial melanoma to identify the chromosomal location of genes which predispose individuals to melanoma; (2) examining tumours cytogenetically to identify frequently rearranged regions of the genome which presumably mark the location of genes involved in the evolution of melanoma; and (3) screening melanomas, using molecular techniques, to identify mutated oncogenes or tumour suppressor genes that play crucial roles in melanoma development. These studies provide strong evidence that genes on chromosomes 1, 6, 7 and 9 are involved in the aetiology of human melanoma.
Cancer Surv 1990
PMID:Genetics of melanoma. 210 27

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.
Br J Cancer 1990 Apr
PMID:Evidence for allosteric variants of wild-type p53, a tumour suppressor protein. 213 77

A novel class of oncogene has been recognised whose loss-of-function results in the expression of the malignant phenotype. Two examples of such genes are the human retinoblastoma predisposition gene (RB1) and the gene encoding the cellular protein p53. These genes are thought to regulate and limit normal proliferation of cells and, as a consequence, can suppress tumorigenicity when introduced into transformed cells. They are hence frequently described as 'tumour suppressor genes'. Both RB1 and p53 gene products are bound by various transforming early proteins encoded by the DNA tumour viruses SV40, adenovirus and human papilloma virus. It is thought that they are thus sequestered and rendered inactive. Thus, a coherent model is emerging whereby inactivation, either by mutation of sequestration, of these tumour suppressor genes may contribute to natural and experimental carcinogenic processes.
Semin Cancer Biol 1990 Dec
PMID:The nuclear oncoproteins: RB and p53. 215 36

In hereditary cancers the responsible inherited cancer genes are defective (mutated) anti-oncogenes (tumour suppressor genes). This inherited mutation is present in all cells of the organism, and only leads to cancer if in a somatic cell a complete set of specific cancer mutations is accumulated. Since one defective anti-oncogene has been inherited, only three additional somatic cancer mutations are required, according to our previously published view (Anticancer Res 10:1990). The number of de novo arising tumour cells in such a person is thus multiplied by a factor equal to the reverse of the mutant frequency, that is about 10(4)-10(5). This can be observed e.g. in retinoblastoma. Mutations occur in proliferating cells only. Consequently cancer mutations also depend on cell proliferation. If an inherited cancer mutation predisposes to cancer formation in certain organs, then the cancer risk in these organs is enhanced by 10(4)-10(5) times. Tumours in these organs will appear simultaneously if the number of cells and the growth kinetics are similar. This is of course observed in paired organs, like the retina and the female breast. In cancer family syndromes different organs may be affected at the same time. Examples are type I and type II cancer family syndrome and multiple endocrine neoplasia type 1 2a, and 2b. The secondly diagnosed tumours are not caused by metastatic spread. Tumours in two organs will arise at difference times if the number of end cells per organ and the growth kinetics differ. In this case the second tumour is called a second primary malignancy and is not caused by metastatic spread. A good example are the second primary malignancies in hereditary retinoblastoma. The inherited defective anti-oncogene is a recessive gene. This defective inherited gene causes a 10(4)-10(5) fold increase of the normal tumour incidence. This means that nearly always one or more tumours will arise. Evidently, this pattern of inheritance has led to the erroneous conclusion that the genetic abnormality is dominant at the level of the chromosome. The 10(4)-10(5) times enhanced tumour incidence in hereditary cancer is helpful for the clinical recognition of hereditary cancer. That is, hereditary cancer can be recognized not only by family history, but also by early occurrence, the multifocal and bilateral localisation, its occurrence as cancer family syndrome or by second primary malignancies. It is thus recommended to screen patients and families with hereditary cancer for first and second primary tumours. Treatment of patients with hereditary tumours requires extra care to avoid additional cancer mutations.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hereditary cancer and its clinical implications: a view. 219 May 27


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