title: Estradiol measurement in translational studies of breast cancer.
abstract: Plasma estrogen measurement with use of radioimmunoassays has been instrumental in the development of aromatase inhibitors for endocrine therapy of postmenopausal breast cancer. However, due to low plasma estrogen concentrations in postmenopausal women, direct radioimmunoassays lack the sensitivity required. While certain laboratories have developed highly sensitive assays for research purposes revealing plasma estrogen suppression consistent with results from tracer studies, such assays are time and labor-consuming due to need for pre-analytical chromatographic purification, sample concentration and sometimes conversion of precursors to products. While novel chromatographic methods involving mass spectrometry analysis are likely to replace such radioimmunoassays in the future, so far a limited number of laboratories have developed suitable assays with a detection limit (around 1 pM) that is required for analyzing plasma estrogen levels in patients during treatment with potent aromatase inhibitors.
authors.affiliation: Institute of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway; Department of Oncology, Haukeland University Hospital, Bergen, Norway. Electronic address: per.lonning@helse-bergen.no.
authors.forename: Per Eystein
authors.initials: PE
authors.lastname: Lønning
mesh_terms: D047072:Aromatase Inhibitors / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy; D004958:Estradiol / Q000032:analysis / Q000097:blood*; D005260:Female; D006801:Humans; D057230:Limit of Detection; D011863:Radioimmunoassay / Q000379:methods*
chemical_list: D047072:Aromatase Inhibitors; D004958:Estradiol
keywords: Aromatase; Breast cancer; Estradiol; Estrogens; Estrone; Radioimmunoassay