Linked Life Data

9067273

Source:http://linkedlifedata.com/resource/pubmed/id/9067273

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1997-4-9
pubmed:abstractText
Estrogen receptors (ER) are routinely measured in tissue extracts from breast cancer using a radioligand binding assay (RBA) and an enzyme immunoassay (EIA). Although good correlation was found between the two methods, they are expected to measure, at least in part, different ER amounts in individual samples, because the RBA should detect unfilled ER only, whereas EIA should recognize both unfilled receptors and those filled by endogenous estrogens. The purpose of the present investigation was to evaluate if ER-EIA mainly detects ER filled by endogenous estrogens when using an estrogen-free buffer to dilute cytosol samples. Indeed, the commercially available EIA assay kit (ER-EIA; Abbott) is equipped with a sample dilution buffer containing a high concentration of 17beta-estradiol which should allow for the saturation of all the ERs. ER was measured in 57 cytosol samples from primary breast cancer with RBA and ER-EIA. In the latter case, samples were diluted using both the estradiol-rich dilution buffer of the kit and an estrogen-free low salt phosphate buffer. RBA and ER-EIA showed tightly correlated results. However, ER-EIA detected higher ER levels than RBA in the majority of cases. Results obtained by low salt ER-EIA were also correlated to both RBA and ER-EIA, showing, however, lower ER concentrations. ER levels measured by ER-EIA were not significantly different from the sum of ER concentrations found by RBA and low salt ER-EIA. These findings suggest that ER-EIA detects ER only in the conformational status that is achieved after saturation by estrogens. These findings were confirmed by sedimentation shift experiments, which showed that the monoclonal antibody D547 used in the kit binds ER in the occupied form only. This leads to the conclusion that ER-EIA detects functioning (in terms of binding with estradiol) ERs. From the present investigation, we suggest that it is possible and probably worthwhile to optimize the EIA method by using different buffers to measure: (a) the total number of ERs capable of binding estradiol; (b) the ER filled by endogenous estrogens; and (c) by difference, the unfilled ER concentrations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
57
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1066-72
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Detection of different estrogen receptor forms in breast cancer cytosol by enzyme immunoassay.
pubmed:affiliation
Centro Regionale Specializzato per lo Studio degli Indicatori Biochimici di Tumore, Ospedale Civile, Campo SS. Giovanni e Paolo, Venezia, Italy.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't