An optimised, highly sensitive radioimmunoassay for the simultaneous measurement of estrone, estradiol and estrone sulfate in the ultra-low range in human plasma samples

Geisler, Jürgen; Ekse, Dagfinn; Helle, Hildegunn; Duong, Nhat K.; Lønning, Per Eystein

doi:10.1016/j.jsbmb.2007.12.011

Cited by 61 publications

(48 citation statements)

References 25 publications

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“…As previously reported [13], after monitored extraction of E 1 S, separation of E 1 S from DHEAS was carried out by chromatography on C 18 Hypersil phase minicolumns (Thermo Fisher, Villebon-sur-Yvette, 91963 Courtaboeuf, France). The chromatographic step was carried out using the Visiprep Vacuum Manifold (Supelco), in order to help the entry of the solvents through the hypersil phase.…”

Section: Ria With Chromatographic Separation (Methods Iii)mentioning

confidence: 99%

“…With method III, DHEAS (the principal steroid in plasma, the level of which was highest) cross-reactivity with the anti-E 1 S antibody was 0.002 %. Moreover, a pre-chromatographic separation of DHEAS from E 1 S on C 18 Hypersil phase minicolumns was carried out. For method IV (DSL-5400 kit), the specificity of this direct method was based only on anti-E 1 S specificity.…”

Section: Specificitymentioning

confidence: 99%

“…The use of radioimmunoassay (RIA) has been well documented in the literature. For routine analysis in clinical laboratories, several authors reported RIA methods [13][14][15][16][17][18]. We described, with accuracy and precision, a specific E 1 S radioimmunoassay involving a chromatographic purification C 18 step [13].…”

Section: Introductionmentioning

confidence: 99%

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Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC–MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Giton¹,

Caron²,

Bérubé³

et al. 2010

Clinica Chimica Acta

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, et al.. Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS).: Plasma estrone sulfate assay in men: comparison between four different assay methods. Clinica Chimica Acta, Elsevier, 2010, 411 (17-18) Acknowledgments:The authors thank Dr. Noah Hardy for editing the manuscript. Methods:We simultaneously assayed estrone sulfate in the plasma of one hundred men aged 30-50 years, according to LC-MS/MS, GC-MS after solvolysis of E 1 S, radioimmunoassay after a chromatographic purification step, and a direct RIA commercial kit.Results: Estrone sulfate plasma levels obtained with the first three methods were not significantly different. However, estrone sulfate levels measured by the direct RIA were threefold higher than those obtained by the first three methods. We showed that the excessively high estrone sulfate levels obtained with the direct RIA kit had two origins:interference by high dehydroepiandrosterone sulfate plasma levels in men, and estrone sulfate inaccurate low concentrations in the standards. Conclusion:The LC-MS/MS method can be considered as an optimum option for clinical laboratory. The GC-MS method requires solvolysis to estrone, but allows simultaneous unconjugated steroid measurement. RIA method, with chromatographic purification, is cumbersome, but less expensive. DSL-5400 kit yielded estrone sulfate plasma levels that were too high.Plasma estrone sulfate assay in men: comparison between four different assay methods 3

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Section: Ria With Chromatographic Separation (Methods Iii)mentioning

confidence: 99%

Section: Specificitymentioning

confidence: 99%

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Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC–MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Giton¹,

Caron²,

Bérubé³

et al. 2010

Clinica Chimica Acta

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“…Women over the age of 40 who have developed CRA or amenorrhea during tamoxifen should measure FSH and estradiol, preferably with a high-quality estradiol assay (i.e., mass spectrometry), which allows a high sensitivity (in the order of pg/ml) together with a high-specificity (no cross reaction with other steroidal molecules) [115]. Women with levels within the premenopausal range (i.e., FSH < 30 UI/L and estradiol > 20 pmol/L), should receive tamoxifen alone or tamoxifen + OFS.…”

Section: Ovarian Reserve Markers and The Choice Of Endocrine Therapy mentioning

confidence: 99%

Chemotherapy-induced ovarian toxicity in patients affected by endocrine-responsive early breast cancer

Torino

Barnabei²,

Vecchis

et al. 2014

Critical Reviews in Oncology/Hematology

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“…), many patients experienced suppression of estradiol below the detection limit of the method (11 out of 12 on anastrozole and 12 out of 12 on letrozole). To solve this problem related to methodologic limitations, we developed a novel, highly sensitive assay for plasma estrogen analysis characterized by the lowest detection limits for plasma estrogens reported thus far (31). Using this improved method, we reanalyzed plasma samples from our cross-over trial (10), comparing anastrozole and letrozole on a head-to-head basis to see whether more sensitive assays may allow a better discrimination between the compounds in this setting.…”

mentioning

confidence: 99%

Letrozole is Superior to Anastrozole in Suppressing Breast Cancer Tissue and Plasma Estrogen Levels

Geisler

Helle

Ekse

et al. 2008

Clinical Cancer Research

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126

113

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Purpose: To evaluate the influence of the third-generation aromatase inhibitor letrozole (Femara) on breast cancer tissue levels of estrone (E 1 ), estradiol (E 2 ), and estrone sulfate (E 1 S) in postmenopausal women undergoing primary treatment for locally advanced estrogen receptor/progesterone receptor^positive breast cancers. Experimental Design: Breast cancer tissue samples were collected before and following 4 months of neoadjuvant therapy with letrozole (2.5 mg o.d.), and tissue estrogen levels measured using a highly sensitive RIA after high-pressure liquid chromatography purification. Results: Letrozole suppressed pretreatment tumor levels of E 2 , E 1 , and E 1 S by 97.6%, 90.7%, and 90.1%, respectively.These data reveal that letrozole suppresses tissue estrogen levels significantly below what has previously been recorded with anastrozole (89.0%, 83.4%, and 72.9% suppression, respectively) using the same methods. To confirm the differential effect of letrozole and anastrozole on each plasma estrogen fraction, we re-analyzed plasma samples obtained from a previous intrapatient cross-over study comparing letrozole and anastrozole using an improved RIA (detection limits of 0.67, 1.14, and 0.55 pmol/L for E 2 , E 1 , and E 1 S, respectively). Letrozole consistently suppressed each plasma estrogen fraction below the levels recorded for anastrozole: E 2 (average suppression by 95.2% versus 92.8%; P = 0.018), E 1 (98.8% suppression versus 96.3%; P = 0.003), and E 1 S (98.9% suppression versus 95.3%; P = 0.003). Conclusion: Our data reveals that letrozole (2.5 mg o.d.) is more effective compared with anastrozole (1.0 mg o.d.) with respect to tissue as well as plasma estrogen suppression in patients with postmenopausal breast cancer.Contemporary clinical studies have shown that three thirdgeneration aromatase inhibitors (anastrozole, letrozole, and exemestane) improve time to progression in metastatic disease (1 -3) and relapse-free as well as overall survival compared with tamoxifen for adjuvant therapy of patients with postmenopausal breast cancer (4 -6). These results are most likely related to their improved potency. The third-generation compounds inhibit total body aromatization by z98% in vivo (7 -10). In contrast, compounds belonging to the first and second generation of inhibitors cause 80% to 90% (11 -14) aromatase inhibition and do not improve clinical outcome compared with tamoxifen or megestrol acetate (see ref. 15).An ongoing controversy relates to potential differences between the three third-generation aromatase inhibitors with respect to mechanism of action (16) and resistance (17), as well as clinical efficacy and safety. Thus, studies in metastatic breast cancer have revealed a lack of complete cross-resistance between nonsteroidal aromatase inhibitors and the steroidal aromatase inactivators (18 -22). However, except for a single study comparing anastrozole and letrozole as second-line therapy in metastatic disease (23), we lack results from direct head-to-head comparisons.Alth...

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An optimised, highly sensitive radioimmunoassay for the simultaneous measurement of estrone, estradiol and estrone sulfate in the ultra-low range in human plasma samples

Cited by 61 publications

References 25 publications

Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC–MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC–MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Chemotherapy-induced ovarian toxicity in patients affected by endocrine-responsive early breast cancer

Letrozole is Superior to Anastrozole in Suppressing Breast Cancer Tissue and Plasma Estrogen Levels

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