Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-12-6
pubmed:abstractText
Choroidal melanoma has a high mortality rate and responds poorly to existing chemotherapy, but unexpected ex vivo sensitivity of a subset of these tumours to topoisomerase II inhibitors has been noted. Since chemoresistance may be mediated by the molecular phenotype of tumours, immunohistochemistry has been used to study the expression of both isoforms of topoisomerase II (alpha and beta) in 29 choroidal melanomas for which chemosensitivity assay data for doxorubicin or mitoxantrone are also available. Of these, eight tumours were topoisomerase II beta-positive and 11 were topoisomerase II alpha-positive. Recent studies showing genetic abnormality (often monosomy of chromosome 3) in choroidal melanoma suggest that loss of immunostaining could be due to genomic loss rather than down-regulation of topoisomerase II beta in these tumours. There was no convincing excess of anthracycline resistance in the topoisomerase II beta-negative group. Addition of topoisomerase II alpha, MDR1 (11/17 positive), LRP (16/28 positive), and MRP (5/29 positive) data in multivariate analysis did not reliably predict sensitivity or resistance. Vincristine chemosensitivity showed no relation to MDR1, LRP or MRP in 18 tumours tested. While it is possible that some tumours which do express topoisomerase II beta may respond to anthracyclines, the molecular basis of resistance or sensitivity to anthracyclines or vincristine in uveal melanoma is complex and remains incompletely understood.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-3417
pubmed:author
pubmed:copyrightInfo
Copyright 2000 John Wiley & Sons, Ltd.
pubmed:issnType
Print
pubmed:volume
192
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
174-81
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed-meshheading:11004693-Adult, pubmed-meshheading:11004693-Aged, pubmed-meshheading:11004693-Aged, 80 and over, pubmed-meshheading:11004693-Antibiotics, Antineoplastic, pubmed-meshheading:11004693-Antineoplastic Agents, pubmed-meshheading:11004693-Antineoplastic Agents, Phytogenic, pubmed-meshheading:11004693-Choroid Neoplasms, pubmed-meshheading:11004693-DNA Topoisomerases, Type I, pubmed-meshheading:11004693-Doxorubicin, pubmed-meshheading:11004693-Drug Resistance, Neoplasm, pubmed-meshheading:11004693-Drug Screening Assays, Antitumor, pubmed-meshheading:11004693-Female, pubmed-meshheading:11004693-Humans, pubmed-meshheading:11004693-Isoenzymes, pubmed-meshheading:11004693-Male, pubmed-meshheading:11004693-Melanoma, pubmed-meshheading:11004693-Middle Aged, pubmed-meshheading:11004693-Mitoxantrone, pubmed-meshheading:11004693-Neoplasm Proteins, pubmed-meshheading:11004693-Predictive Value of Tests, pubmed-meshheading:11004693-Vincristine
pubmed:year
2000
pubmed:articleTitle
Relationship between expression of topoisomerase II isoforms and chemosensitivity in choroidal melanoma.
pubmed:affiliation
Department of Pathology, Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK.
pubmed:publicationType
Journal Article