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

A characteristic feature of colorectal cancer genesis is its stepwise progression, which offers unique possibilities for studying its development. There are two principal kinds of mutation leading to uncontrolled cell proliferation and cancer. The first renders a stimulatory gene hyperactive--generation of an oncogene--and the second is the inactivation of a tumour suppressor gene. Current knowledge suggest that the change from normal mucosa to a small adenoma may be mediated by mutations of the APC gene and MCC gene on chromosome 5, by chromosome 5 deletion, by c-myc activation, and by DNA hypomethylation. The development to a large adenoma may be caused by Ki-ras mutation and further change to a dysplastic adenoma by deletion of the DCC gene on chromosome 18. The ability to become an invasive carcinoma may then be mediated by p53 mutations and deletion of chromosome 17p. Identification of genetic markers for metastatic disease is under progress.
 ...
PMID:Genetic aspects of colorectal cancer: the surgeon's view. 889 51

The development and progression of cancer are known to be regulated by various oncogenes and tumour suppressor genes. We analysed 63 primary malignant salivary gland tumours for the expression of p53 and c-erbB-2 proteins. Immunohistochemically, 7 of 63 tumours (11%) showed diffuse nuclear staining for p53 protein, and all 7 were also positive for c-erbB-2 protein. The overexpression of p53 protein correlated closely with the overexpression of c-erbB-2 protein (P<0.001). Overexpression of both p53 and c-erbB-2 proteins (coexpression) was found in tumours of certain histological types, such as adenocarcinoma, carcinoma in pleomorphic adenoma, and salivary duct carcinoma. Furthermore, it is noteworthy that coexpression was associated with high-grade carcinoma, advanced tumour stage, and a high Ki-67 labelling index (%) which is a marker of cell proliferation. In adenocarcinoma, we attempted to clarify the relationship between coexpression and histological grade. Coexpression was associated with histological grades showing high mitotic indices and necrotic areas, which reflected high cell-proliferative activity. These results suggest that the accumulation of genetic alterations, such as those involving p53 and c-erbB-2, plays an important part in the progression of malignant salivary gland tumours.
 ...
PMID:Coexpression of p53 and c-erbB-2 proteins is associated with histological type, tumour stage, and cell proliferation in malignant salivary gland tumours. 892 28

The development of colorectal carcinoma from adenomas is recognized as the dominant mechanism of colon carcinogenesis. However, early colon carcinomas are being increasingly detected which have no adenomatous elements in their vicinity, and which, despite their small size, already show submucosal invasion. Such tumours (so-called 'de novo' carcinomas) have renewed consideration of the de novo colorectal carcinogenesis pathway. The goal of this study was to evaluate the expression of tumour suppressor gene p53 and apoptosis control gene bcl-2 in de novo carcinomas, compared with early carcinomas developing in the background of an adenoma (ex-adenoma). Fifty cases each of de novo and ex-adenoma carcinomas (pT1) were studied. p53 expression was significantly higher in the de novo carcinomas than in the ex-adenoma carcinomas (62 per cent vs. 42 per cent), while bcl-2 tended to be weaker in the de novo than in the ex-adenoma carcinomas. These differences' support the concept that de novo carcinomas are a unique pathological entity, with a phenotype reflecting their more aggressive behaviour.
 ...
PMID:Expression of bcl-2 and p53 in de novo and ex-adenoma colon carcinoma: a comparative immunohistochemical study. 895 2

Many human cancer susceptibility genes have been successfully mapped by genetic linkage studies. One that has so far eluded researchers is that for Peutz-Jeghers (P-J) syndrome, a condition characterized by intestinal hamartomatous polyposis and melanin spots of the lips, buccal mucosa and digits. A dramatically elevated risk of malignancy has also been documented. Gastrointestinal tumours as well as cancers of the breast, ovary, testis and uterine cervix appear to be overrepresented in families with this syndrome. The nature of hamartomatous polyps is equivicol. Hamartomas are usually considered histologically benign, but in the case of Peutz-Jeghers patients, there are reports of adenomatous and malignant changes in the polyps, and the possibility of a hamartoma-carcinoma sequence has been discussed. A search for a putative tumour suppressor locus was made using comparative genomic hybridization (CGH) of Peutz-Jeghers polyps, combined with loss of heterozygosity (LOH) study. Genetic linkage analysis in 12 families using markers from a deletion site demonstrated the presence of a high-penetrance locus in distal 19p with a multipoint lod score of 7.00 at marker D19S886 without evidence of genetic heterogeneity. The study demonstrates the power of CGH combined with LOH analysis in identifying putative tumour suppressor loci, and provides molecular evidence of malignant potential in hamartomas.
 ...
PMID:Localization of a susceptibility locus for Peutz-Jeghers syndrome to 19p using comparative genomic hybridization and targeted linkage analysis. 898 57

Abnormalities in the p53 tumour suppressor gene and in the expression of its protein are common in colorectal carcinoma. The prognostic significance of these p53 abnormalities was studied in 66 patients with colorectal cancer, followed for more than 10 years. Single-strand conformation polymorphism (SSCP) analysis was used to detect alterations in exons 5-8 of the p53 gene. Paraffin sections were examined immunohistochemically for p53 overexpression with the monoclonal antibody DO-7 (Dako) both with and without microwave antigen retrieval. Abnormalities of the p53 gene were found in 41 per cent of cases by SSCP analysis. Outcome was unrelated to SSCP abnormalities (P = 0.19), except for the Dukes' A and B subgroup, where decreased survival was found in cases with abnormal SSCP (P = 0.01). Overexpression of p53 protein was seen by immunohistochemistry in 47 per cent of cases without, and in 52 per cent of cases with microwave antigen retrieval. Immunohistochemical overexpression of p53 protein either with or without microwave antigen retrieval was an independent prognostic indicator of poor survival. These results suggest that for routine purposes, immunohistochemical detection of the p53 protein product may be more useful than SSCP analysis of the encoding p53 gene in identifying those at high risk of colorectal cancer recurrence and death.
 ...
PMID:Prognostic significance of p53 abnormalities in colorectal carcinoma detected by PCR-SSCP and immunohistochemical analysis. 901 55

The molecular mechanism of gastric tumourigenesis has not yet been clarified, although investigators have postulated that differentiated adenocarcinoma may arise from pre-existing adenoma, similarly to the colorectal adenoma-carcinoma sequence. An allelotype analysis has been performed to identify chromosomal regions which are frequently deleted in gastric tumours and to examine the significance of the adenoma-carcinoma sequence in gastric tumourigenesis. Forty-five gastric tumours, 20 adenomas, and 25 differentiated adenocarcinomas were examined for loss of heterozygosity (LOH) using 39 microsatellite markers covering each non-acrocentric chromosome arm. Frequent LOH in the adenocarcinomas was observed on chromosomes 2q (33 per cent), 4p (33 per cent), 5q (50 per cent), 6p (33 per cent), 7q (43 per cent), 11q (36 per cent), 14q (38 per cent), 17p (45 per cent), 18q (36 per cent), and 21q (40 per cent). In contrast, the incidence of LOH in adenomas did not exceed 10 per cent at any of the loci examined. In addition to the p53 gene on 17p and the DCC gene on 18q, which are known to be frequently deleted in differentiated adenocarcinomas of the stomach, other unknown tumour suppressor genes on the above-mentioned chromosomes may also be inactivated. These observations suggest that the adenoma-carcinoma sequence is not a major pathway in gastric tumourigenesis.
 ...
PMID:Allelotype of adenoma and differentiated adenocarcinoma of the stomach. 901 56

Breast cancer emerges as a multistep process with transformation of normal cells via steps of hyperplasia, premalignant change and in situ carcinoma. Cytogenetic and molecular genetic analyses of breast cancer samples indicate that tumour development involves the accumulation of various genetic alterations, including amplification of oncogenes and mutation or loss of tumour suppressor genes. Microdissection of histological sections is needed to correlate the specific histological change and the genetic alteration. For detection of oncogene amplification quantitative differential polymerase chain reaction (PCR) can be used. For assessment of loss of heterozygosity PCR-based microsatellite polymorphisms detecting differences in short tandem repeat sequences are much more informative than standard two-allele restriction fragment length polymorphism markers. Still, the direct correlation of the genetic alterations to specific histological findings is the key to reveal insight into tumour biology and thereby gain prognostic information for the individual breast cancer patient.
 ...
PMID:Detection of sequential genetic alterations relevant for breast cancer development. 906 Dec 83

Deletions involving regions of chromosome 10 occur in the vast majority (> 90%) of human glioblastoma multiformes. A region at chromosome 10q23-24 was implicated to contain a tumour suppressor gene and the identification of homozygous deletions in four glioma cell lines further refined the location. We have identified a gene, designated MMAC1, that spans these deletions and encodes a widely expressed 5.5-kb mRNA. The predicted MMAC1 protein contains sequence motifs with significant homology to the catalytic domain of protein phosphatases and to the cytoskeletal proteins, tensin and auxilin. MMAC1 coding-region mutations were observed in a number of glioma, prostate, kidney and breast carcinoma cell lines or tumour specimens. Our results identify a strong candidate tumour suppressor gene at chromosome 10q23.3, whose loss of function appears to be associated with the oncogenesis of multiple human cancers.
 ...
PMID:Identification of a candidate tumour suppressor gene, MMAC1, at chromosome 10q23.3 that is mutated in multiple advanced cancers. 909 Mar 79

We report on an adenoid cystic-carcinoma (ACC) with a clonal deletion of 17p as the only karyotypic abnormality. Using different chromosome 17-derived probes we showed by FISH that the deletion encompassed the p53 tumour suppressor gene. Immunohistochemical analysis revealed overexpression of p53 protein in a subpopulation of cells, suggesting a mutation in the remaining p53 allele in these cells. Our findings provide novel information about possible progressional pathways in ACC, and demonstrate the value of combining conventional cytogenetic analysis with-molecular cytogenetic and immunohistochemical methods. This approach is particularly useful in cases with minor cytogenetic abnormalities at the border of visibility.
 ...
PMID:Observations by chromosome banding, FISH and immunohistochemistry in an adenoid cystic carcinoma with del(17)(p13) as the sole deviation. 913 46

We have previously shown that expression of gp200-MR6, a molecule that is functionally associated with the interleukin-4 receptor (IL-4R), is lost from breast carcinoma cells as malignancy increases. Here we have analysed a series of colorectal carcinoma cell lines and show a similar decrease with increasing malignancy. Moreover, analysis of the HRA-19 cell line, which can exhibit a poorly or a well-differentiated phenotype according to culture conditions, shows that gp200-MR6 is weakly expressed on the former but strongly expressed on the latter. Functional analysis using either IL-4 or monoclonal antibody (MAb) MR6 and the well-differentiated cell line SW1222 revealed that MAb MR6 acts as an agonist for IL-4, with both reagents causing a dose-dependent inhibition of cell division, but greatly enhancing the glandular differentiation of SW1222 in three-dimensional collagen gels. These observations suggest that the gp200-MR6 molecule may act as the product of a tumour suppressor gene and that its loss may be a primary event in tumourigenesis.
 ...
PMID:Inhibition of growth and enhancement of differentiation of colorectal carcinoma cell lines by MAb MR6 and IL-4. 917 15


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>