title: Within-person variability of the ratios of urinary 2-hydroxyestrone to 16alpha-hydroxyestrone in Caucasian women.
abstract: The ratio of urinary 2-hydroxyestrone (2-OHE1) to 16alpha-hydroxyestrone (16alpha-OHE1) has been suggested as a potential biomarker for breast cancer risk. We evaluated within-person variability of this biomarker in ten healthy Caucasian women aged 23-58 years. Each study participant was asked to provide an overnight fasting morning urine sample once a week for an average of 8 weeks. These urine samples were assayed for 2-OHE1 and 16alpha-OHE1 by using competitive enzyme immunoassay kits purchased from the ImmunaCare Corporation. The coefficients of variation for urinary 2-OHE1/16alpha-OHE1 over the study period ranged from 13.7 to 59.6% (mean, 33.3%) in our study participants. There was a good correlation between the level of the urinary 2-OHE1/16alpha-OHE1 ratio in any single urine sample and the average ratio over the 8-week study period from the same woman, with the mean correlation coefficient of 0.85. These results indicated that the within-person variation of the 2-OHE1 to 16alpha-OHE1 ratio for most women was moderate and the level of this ratio in a single urine sample, in general, reflects reasonably well the level of this biomarker over a 2-month period.
authors.affiliation: Molecular Epidemiology Unit, University of South Carolina School of Public Health and South Carolina Cancer Center, Columbia 29203, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: W
authors.initials: W
authors.lastname: Zheng
authors.forename: L M
authors.initials: LM
authors.lastname: Dunning
authors.forename: K G
authors.initials: KG
authors.lastname: Anderson
authors.forename: R S
authors.initials: RS
authors.lastname: Parrish
authors.forename: J L
authors.initials: JL
authors.lastname: Holtzman
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000652:urine*; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D015203:Reproducibility of Results; D044465:White People
chemical_list: D006894:Hydroxyestrones; C026702:16-hydroxyestrone; C024980:2-hydroxyestrone