Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Loss of heterozygosity (LOH) involving 3p occurs in many carcinomas but is complicated by the identification of four distinct homozygous deletion regions. One putative target, 3p14.2, contains the common fragile site, FRA3B, a hereditary renal carcinoma-associated 3;8 translocation and the candidate tumor suppressor gene, FHIT. Using a approximately 300 kb comsid/lambda contig, we identified homozygous deletions in cervix, breast, lung and colorectal carcinoma cell lines. The smallest deletion (CC19) was shown not to involve FHIT coding exons and no DNA sequence alterations were present in the transcript. We also detected discontinuous deletions as well as deletions in non-tumor DNAs, suggesting that FHIT is not a selective target. Further, we demonstrate that some reported FHIT aberrations represent normal splicing variation. DNA sequence analysis of 110 kb demonstrated that the region is high in A-T content, LINEs and MER repeats, whereas Alu elements are reduced. We note an intriguing similarity in repeat sequence composition between FRA3B and a 152 kb segment from the Fragile-X region. We also identified similarity between a FRA3B segment and a small polydispersed circular DNA. In contrast to the selective loss of a tumor suppressor gene, we propose an alternative hypothesis, that some putative targets including FRA3B may undergo loss as a consequence of genomic instability. This instability is not due to DNA mismatch repair deficiency, but may correlate in part with p53 inactivation.
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PMID:Chromosome 3p14 homozygous deletions and sequence analysis of FRA3B. 906 39

Alterations of the TP53 gene were analyzed in samples from 87 primary breast cancer patients, using molecular and immunohistochemical approaches. Mutations were detected in 17% of the samples, using polymerase chain reaction (PCR) and constant denaturant gel electrophoresis (CDGE) on exons 5-8 of the TP53 gene, and were confirmed by sequencing. Abnormal TP53 protein staining was found in 55% of the primary samples, using the monoclonal TP53 antibody DO7. A statistically significant association was found between TP53 mutations and abnormal protein staining (p = 0.002). Our results suggest that dysfunction of the TP53 protein is associated with tumor progression, as we found an association between TP53 abnormalities and accumulation of genetic lesions, measured as overall allelic imbalance (AI), homogeneously staining regions (HSR) and strong ERBB2 overexpression. Furthermore, patients with TP53 mutation had a highly elevated risk of dying from breast cancer during the study period (p < 0.001, RR = 10.68) at a median follow-up time of 42 months. Abnormal TP53 staining was much more frequent than the mutations, but it was not of prognostic significance, whereas strong staining was an independent prognostic factor. We therefore conclude that loss of functional TP53 leads to genetic instability, resulting in poorer short-term prognosis, and that only strong staining of TP53, and not abnormal protein staining in general, is of prognostic significance.
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PMID:Genomic instability and poor prognosis associated with abnormal TP53 in breast carcinomas. Molecular and immunohistochemical analysis. 911 74

The recent highlighted points in prognostic factors after breast cancer operation include: 1) the emergence of many genetic and biochemical markers, including c-erbB-2, int-2, EGFR, p53, nm23, LOH, E cadherin, s-phase fraction. The prognostic value of these factors is related to their role in cell cycle regulation, invasion/metastasis mechanisms, etc. The agents related to therapeutic effectiveness, namely p-glycoprotein, pS2, and bcl-2 may become important stratification factors when conducting clinical trials. Pathologic factors, like nodal status, however, are the most useful prognostic factors at the moment. Many newly developed prognostic factors should be examined by multivariate analysis and validated prospectively before clinical use.
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PMID:[Recent prognostic factors for breast cancer]. 912 98

Thirty percent of human breast cancers have amplification of ERBB2, often in conjunction with mutations in p53. The most common p53 mutation in human breast cancers is an Arg-to-His mutation at codon 175, an allele that functions in a dominant oncogenic manner in tumorigenesis assays and is thus distinct from loss of p53. Transgenic mice expressing mouse mammary tumor virus-driven neu transgene (MMTV-neu) develop clonal mammary tumors with a latency of 234 days, suggesting that other events are necessary for tumor development. We have examined the role of mutations in p53 in tumor development in these mice. We have found that 37% of tumors arising in these mice have a missense mutations in p53. We have directly tested for cooperativity between neu and mutant p53 in mammary tumorigenesis by creating bitransgenic mice carrying MMTV-neu and 172Arg-to-His p53 mutant (p53-172H). In these bitransgenic mice, tumor latency is shortened to 154 days, indicating strong cooperativity. None of the nontransgenic mice or the p53-172H transgenic mice developed tumors within this time period. Tumors arising in the p53-172H/neu bitransgenic mice were anaplastic and aneuploid and exhibited increased apoptosis, in distinction to tumors arising in p53-null mice, in which apoptosis is diminished. Further experiments address potential mechanisms of cooperativity between the two transgenes. In these bitransgenic mice, we have recapitulated two common genetic lesions that occur in human breast cancer and have shown that p53 mutation is an important cooperating event in neu-mediated oncogenesis.
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PMID:neu/ERBB2 cooperates with p53-172H during mammary tumorigenesis in transgenic mice. 915 14

Chromosome 17 is one of the most frequently altered chromosomes in malignant breast cancer. At least four genes implicated in breast cancer reside on chromosome 17 (p53, 17p13; Her-2/neu/ERBB2, 17q12; BRCA1, 17q21; and nm23, 17q22). In addition, allelic imbalance has been described for at least five regions of chromosome 17. We have previously shown that the introduction of a normal human chromosome 17 into the breast cancer cell line MCF7 by microcell mediated chromosome transfer (MMCT) results in the in vitro growth arrest of these cells within 8 weeks, suggesting the presence of a growth suppressor on chromosome 17. Additionally, we have shown that the tumor suppressor gene p53 is not responsible for this phenotype, as it is wild type in MCF7 cells, and overexpression has no effect on either the in vitro or in vivo growth of these cells. We have further localized this growth suppressor gene to 17q24-q25 by transfer of chromosome 17 hybrids containing defined deletions. Whereas transfer of hybrids that contained an intact 17q (delta43/A9 and delta26/A9) resulted in growth arrest, two hybrids with overlapping deletions at 17q24-q25, had no effect on growth of MCF7 cells. Molecular analyses revealed that 50/70 (71%) of the resulting delta2/MCF7 or delta624/MCF7 MMCT clones retained an intact introduced chromosome 17. In contrast, only 8/34 (24%) of delta43/MCF7 revertants (deleted for 17p13.1-pter) which escaped growth arrest showed no breakage of the introduced chromosome 17. We did not observe a preferential loss of an intragenic BRCA1 marker in the MMCT hybrids, excluding BRCA1 as the gene responsible for this growth arrest phenotype. These data therefore implicate a new growth suppressor gene involved in breast cancer that is localized to chromosome 17q24-q25.
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PMID:Localization of a growth suppressor activity in MCF7 breast cancer cells to chromosome 17q24-q25. 917 10

Glioblastoma multiforme (GBM) can be divided into genetic subsets: approximately one-third of GBM, primarily in older adults, have EGFR amplification; another one-third, primarily in younger adults, have TP53 mutation. The majority of GBM also have homozygous deletions of the CDKN2 (p16/MTS1) gene, resulting in cell cycle deregulation and elevated proliferation indices. We evaluated the relationship between CDKN2 deletions and the GBM subsets as defined by EGFR amplification or TP53 mutation in 70 GBM. Twenty-eight cases (40%) had EGFR amplification, 21 (30%) had TP53 mutation, and 21 (30%) had neither change. CDKN2 deletions were present in 36 (51%) GBM. Of the 28 GBM with EGFR amplification, 20 (71%) had CDKN2 deletion (p = 0.0078). The remaining 16 cases with CDKN2 loss were divided between GBM with TP53 mutations (6 cases) and GBM with neither EGFR amplification nor TP53 mutation (10 cases). Thus, CDKN2 deletions occur twice as commonly in GBM with EGFR amplification (71%) than in GBM with TP53 mutation (29%). CDKN2 deletions occurred in GBM from patients somewhat older than those patients with GBM lacking CDKN2 deletion (mean age 53 vs. 48 years). Specifically among GBM with EGFR amplification, those with CDKN2 deletions also occurred in patients slightly older than those few GBM without CDKN2 deletions (mean age 55 vs. 51 years). The presence of CDKN2 deletions in most GBM with EGFR amplification and in generally older patients may provide one explanation for the potentially more aggressive nature of such tumors.
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PMID:Association of EGFR gene amplification and CDKN2 (p16/MTS1) gene deletion in glioblastoma multiforme. 921 72

The evolution of cancer is a multistep phenomenon, and multiple cellular genetic lesions are involved in the emergence of the malignant neoplasm. Several early events have been implicated in the neoplastic transformation of thyrocytes, and recent reports have described the involvement of specific genetic alterations in different types of thyroid neoplasms: ras point mutations are frequently observed in tumours with follicular histology, gsp-the mutated form of the alpha subunit of the Gs-protein-is encountered in up to 73% of papillary or follicular thyroid carcinomas, and a high prevalence of p53 point mutations has been found in anaplastic thyroid carcinomas but not in differentiated follicular tumours. More recent studies revealed that the RET proto-oncogene is involved in the oncogenesis of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) by activation of its tyrosine kinase either by point mutation or rearrangement. In this review the most important recently published data on alterations of the RET proto-oncogene in heritable and sporadic MTCs and in PTCs will be summarized. Emphasis will be directed to the pathophysiological mechanisms of tumour initiation, the indications and limitations of DNA testing, and the clinical implications of identified RET defects in thyroid lesions.
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PMID:The RET proto-oncogene in medullary and papillary thyroid carcinoma. Molecular features, pathophysiology and clinical implications. 924 27

Glioblastomas (GBMs) are a heterogeneous group of tumors. Recently, distinct molecular genetic alterations have been linked to subgroups of patients with GBM. Giant cell (gc)GBMs are a rare variant of GBM characterized by a marked preponderance of multinucleated giant cells. Several reports have associated this entity with a more favorable prognosis than the majority of GBMs. To evaluate whether gcGBM may also represent a genetically defined subgroup of GBM, we analyzed a series of 19 gcGBMs for mutations in the TP53 gene for amplification of the EGFR and CDK4 genes and for homozygous deletions in the CDKN2A (p16/MTS1) gene. Seventeen of nineteen gcGBMs carried TP53 mutations whereas EGFR and CDK4 gene amplification was seen in only one tumor each and homozygous deletion of CDKN2A was not observed at all. The strikingly high incidence of TP53 mutations and the relative absence of other genetic alterations groups gcGBM together with a previously recognized molecular genetic variant of GBM (type 1 GBM). It is tempting to speculate that the better prognosis of gcGBM patients may result from the low incidence of EGFR amplification and CDKN2A deletion, changes known for their growth-promoting potential.
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PMID:Molecular genetic analysis of giant cell glioblastomas. 928 34

Primary glioblastomas develop rapidly de novo through a genetic pathway characterized by amplification/overexpression of EGFR and of MDM2 genes. Secondary glioblastomas develop more slowly through progression from low grade or anaplastic astrocytoma and show a high incidence of a p53 mutation. In the present study, primary and secondary glioblastomas were analyzed for p16 deletions and CDK4 amplification by differential PCR and for loss of expression of the retinoblastoma (RB) gene by immunohistochemistry. Except for one case, alterations in the structure or expression of p16, CDK4 and RB were mutually exclusive. The overall incidence of aberrant expression of these genes coding for components of the cell-cycling-regulatory system was similar in primary (14/28; 50%) and secondary glioblastomas (9/23; 39%). However, p16 deletions were significantly more frequent in the former (10/28; 36%) than in the latter (1/23, 4%; P = 0.0075), suggesting that this alteration constitutes an additional genetic hallmark of the primary (de novo) glioblastoma.
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PMID:Alterations of cell cycle regulatory genes in primary (de novo) and secondary glioblastomas. 934 29

We studied a family in which thyroid neoplasms appeared to occur through genetic inheritance. Six blood relations, including the two probands, had thyroid carcinoma, and six others had benign thyroid tumors. When both parents had a thyroid neoplasm, their children frequently had thyroid neoplasms; this was confirmed through two generations of this family. To clarify the mechanism of inheritance, we performed chromosomal analysis, Southern blot analysis of three variable number of tandem repeats markers and HLA typing on two probands, and examined their RET proto-oncogenes, and p53 and RB tumor suppressor genes. We could not find any positive data on genetic analysis, although our data were limited. In conclusion, we studied a family in which thyroid neoplasms have occurred partly through genetic inheritance, although environmental factors may have influenced the occurrence of thyroid diseases. A search for a predisposing gene, using the microsatellite technique, is required to clarify the gentic factors involved.
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PMID:Clinical and genetic analysis of an inherited case of thyroid adenoma/cancer. 936 3


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