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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2001-6-6
pubmed:abstractText
Deletions of chromosome band 18q21 appear with very high frequency in a variety of carcinomas, especially in colorectal cancer. Potent tumor suppressor genes located in this region encode transforming growth factor beta (TGF-beta) signal transducers SMAD2 and SMAD4, and inactivation of either one leads to impaired TGF-beta-mediated cell growth/apoptosis. Following the assignment of SMAD7 to 18q21, we first refined the SMAD7 gene position within this region by genetically mapping SMAD7 between SMAD2 and SMAD4. Further, to compare the respective frequencies of genetic alterations of these three SMAD genes in colorectal cancer, we undertook a large-scale evaluation of the copy status of each of these genes on DNA samples from colorectal tumor biopsy material. Among a subset of 233 DNA samples for which data were available for all four genes, SMAD4, SMAD2, and the nearby gene DCC showed high deletion rates (66%, 64%, and 59%, respectively), whereas SMAD7 was deleted in only 48% of the tumors. Unexpectedly, we found some gene duplications; SMAD7 appears to be more frequently amplified (10%) than the three other genes (4-7%). Compiled data for SMAD genes in each tumor show that the most common combination (26% of all the tumors) consists of the simultaneous deletions of SMAD2 and SMAD4 associated with normal diploidy or even duplication of SMAD7. Since SMAD7 normally counteracts SMAD2 and SMAD4 in TGF-beta signaling, we hypothesize that the tumor might not benefit from simultaneous SMAD7 inactivation, thereby exerting selective pressure to retain or even to duplicate the SMAD7 gene.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1045-2257
pubmed:author
pubmed:copyrightInfo
Copyright 2001 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
240-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Combined copy status of 18q21 genes in colorectal cancer shows frequent retention of SMAD7.
pubmed:affiliation
Department of Research, University Hospital of Basel, Basel, Switzerland. jean-louis.boulay@unibas.ch
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't