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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-1-11
pubmed:abstractText
Analysis of APC mutations in colonic and duodenal tumours from familial adenomatous polyposis (FAP) patients has shown that the site of the first hit, the germline mutation, can predict the type and position of the somatic mutation or 'second hit'. The two APC mutations are selected on the basis of a 'just right' level of beta-catenin signalling in intestinal tumours achieved through retention of some of the seven 20-amino-acid beta-catenin degradation repeats. Desmoids are a life threatening extra-colonic manifestation in FAP patients. These aggressive tumours of mesenchymal origin are, at present, poorly characterized in terms of mutational APC spectra. We have investigated somatic mutations in the largest cohort of FAP-associated desmoids to date, and combined our results with previously published data. Somatic mutations were found to occur non-randomly and the position of the germline mutation shown to be a major determinant of the somatic mutation, a characteristic shared with intestinal tumours from FAP patients. In contrast to colonic polyps, loss of heterozygosity in desmoids involved deletion rather than mitotic recombination. While tumours from the colorectum and upper gastrointestinal tract usually retain one to two and three to four beta-catenin degradation repeats, respectively, most desmoids preferentially retain two repeats (P < 0.001, chi2 test). In addition, most desmoids with two APC hits (87%, 26/30) had one mutated allele with no 20-amino acid repeats (P < 0.001). This feature, unique among FAP tumours, indicates that a mutation deleting all repeats from one allele may be an important component in maintaining appropriate levels of beta-catenin signalling levels in desmoid tumour cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0964-6906
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
78-82
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
APC mutations in FAP-associated desmoid tumours are non-random but not 'just right'.
pubmed:affiliation
Polyposis Registry, Cancer Research UK, St Mark's Hospital, Harrow, Middlesex HA1 3UJ, UK.
pubmed:publicationType
Journal Article