An enzyme immunoassay compared with a ligand-binding assay for measuring progesterone receptors in cytosols from breast cancers.

1988 ◽  
Vol 34 (6) ◽  
pp. 1116-1118 ◽  
Author(s):  
C M Smyth ◽  
D E Benn ◽  
T S Reeve
Keyword(s):  
Breast Cancer ◽  
Ligand Binding ◽  
Least Squares ◽  
Enzyme Immunoassay ◽  
Binding Assay ◽  
Progesterone Receptors ◽  
Ligand Binding Assay ◽  
Breast Cancers ◽  
Best Fit ◽  
Very High

Abstract To assay progesterone receptor (PR), we compared Abbott's enzyme immunoassay (PR-EIA) with a ligand-binding assay involving dextran-coated charcoal (PR-DCC), using cytosols prepared from 109 breast-cancer biopsies. Results by the two PR methods agreed well. Least-squares analysis produced a line of best fit having a slope of 0.88, an intercept on the PR-EIA axis of 16 fmol per milligram of protein, and a correlation coefficient (r2) of 0.87. To evaluate whether accurate PR-EIA measurements could be obtained on stored cytosols, we compared PR-EIA values for fresh cytosols with values for cytosols stored for various lengths of time up to 13 weeks. Agreement was excellent, especially when the samples showing very high binding (greater than 600 fmol per milligram of protein) were excluded. The lines of best fit after least-squares analyses of the remaining values had slopes between 1.0 and 1.1, intercepts less than 3 fmol/mg, and r2 all greater than 0.91.

Estrogen Receptor Status by Immunohistochemistry Is Superior to the Ligand-Binding Assay for Predicting Response to Adjuvant Endocrine Therapy in Breast Cancer

1999 ◽  
Vol 17 (5) ◽  
pp. 1474-1474 ◽  
Author(s):  
Jennet M. Harvey ◽  
Gary M. Clark ◽  
C. Kent Osborne ◽  
D. Craig Allred
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Clinical Outcome ◽  
Ligand Binding ◽  
Endocrine Therapy ◽  
Binding Assay ◽  
Adjuvant Endocrine Therapy ◽  
Ligand Binding Assay ◽  
Breast Cancers ◽  
Er Status

PURPOSE: Immunohistochemistry (IHC) is a newer technique for assessing the estrogen receptor (ER) status of breast cancers, with the potential to overcome many of the shortcomings associated with the traditional ligand-binding assay (LBA). The purpose of this study was to evaluate the ability of ER status determination by IHC, compared with LBA, to predict clinical outcome—especially response to adjuvant endocrine therapy—in a large number of patients with long-term clinical follow-up. PATIENTS AND METHODS: ER status was evaluated in 1,982 primary breast cancers by IHC on formalin-fixed paraffin-embedded tissue sections, using antibody 6F11 and standard methodology. Slides were scored on a scale representing the estimated proportion and intensity of positive-staining tumor cells (range, 0 to 8). Results were compared with ER values obtained by the LBA in the same tumors and to clinical outcome. RESULTS: An IHC score of greater than 2 (corresponding to as few as 1% to 10% weakly positive cells) was used to define ER positivity on the basis of a univariate cut-point analysis of all possible scores and disease-free survival (DFS) in patients receiving any adjuvant endocrine therapy. Using this definition, 71% of all tumors were determined to be ER-positive by IHC, and the level of agreement with the LBA was 86%. In multivariate analyses of patients receiving adjuvant endocrine therapy alone, ER status determined by IHC was better than that determined by the LBA at predicting improved DFS (hazard ratios/P = 0.474/.0008 and 0.707/.3214, respectively) and equivalent at predicting overall survival (0.379/.0001 and 0.381/.0003, respectively). CONCLUSION: IHC is superior to the LBA for assessing ER status in primary breast cancer because it is easier, safer, and less expensive, and has an equivalent or better ability to predict response to adjuvant endocrine therapy.

scholarly journals Single-point versus five-point biochemical method for determination of estrogen and progesterone receptors

2002 ◽  
Vol 21 (1) ◽  
pp. 15-20
Author(s):  
Dragica Nikolic-Vukosavljevic ◽  
Milan Markicevic ◽  
Sladjana Todorovic
Keyword(s):  
Quality Control ◽  
Breast Carcinoma ◽  
Ligand Binding ◽  
Binding Assay ◽  
Single Point ◽  
Progesterone Receptors ◽  
Medical Decision ◽  
Ligand Binding Assay ◽  
Estrogen And Progesterone Receptors

Receptors for estrogen and progesterone are accepted by international consensus as biomarkers of breast carcinoma responsiveness to endocrine therapy. Numerous current studies are aimed at consideration of importance of "the new generation" of estrogen-regulated biomarkers in treatment of breast cancer patients. Simultaneous knowledge of all these biomarkers may help in medical decision making. However, the amount of tumor material available from breast carcinoma can make impossible determination of estrogenregulated biomarkes together with estrogen and progesterone receptors. To assess whether we could replace our current five-point ligand binding assay for measurement of estrogen and progesterone receptors with a single- point ligand binding assay, we compared simultaneous measurements in same samples of breast carcinomas by both methods. A linear regression analysis shows that single-point assay can be confidently used instead of five-point assay. In addition, there were no variations over time in estrogen and progesterone receptors phenotypes, as well as in estrogen and progesterone receptors contents determined by single-point assay. Accordingly, the results clearly demonstrate the validity of intralaboratory quality control and give a possibility for the establishment of interlaboratory quality control of single-point ligand binding assay.

TBG MEASUREMENTS BY COMPETITIVE LIGAND BINDING ASSAY (CLBA)

1975 ◽  
Vol 80 (1_Suppla) ◽  
pp. S15
Author(s):  
K. H. Rudorff ◽  
H. J. Kröll ◽  
J. Herrmann
Keyword(s):  
Ligand Binding ◽  
Binding Assay ◽  
Ligand Binding Assay ◽  
Competitive Ligand
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