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Reproductive Biology and Endocrinology

, 8:93

First Online: 02 August 2010Received: 07 May 2010Accepted: 02 August 2010


BackgroundAn important aspect of the link between estrogen and breast cancer is whether urinary estrogen levels are representative of the intra-tissue levels of bioavailable estrogens.

MethodsThis study compares 15 estrogen and estrogen metabolite levels in breast tissue and urine of 9 women with primary breast cancer using a quantitative liquid chromatography-mass spectrometry method.

ResultsThe average levels of estrogens estrone, 17 beta-estradiol were significantly higher in breast tissue than in urine. Both the 2 and the 16-hydroxylation pathways were less represented in breast tissue than urine; no components of the 4-hydroxypathway were detected in breast tissue, while 4-hydroxyestrone was measured in urine. However, the 2-16 ratio was similar in urine and breast tissue. Women carrying the variant CYP1B1 genotype Leu-Val and Val-Val showed significantly lower overall estrogen metabolite, estrogen, and 16-hydroxylation pathway levels in breast tissue in comparison to women carrying the wild type genotype. No effect of the CYP1B1 polymorphism was observed in urinary metabolites.

ConclusionsThe urinary 2-16 ratio seems a good approximation of the ratio observed in breast tissue. Metabolic genes may have an important role in the estrogen metabolism locally in tissues where the gene is expressed, a role that is not readily observable when urinary measurements are performed.

Electronic supplementary materialThe online version of this article doi:10.1186-1477-7827-8-93 contains supplementary material, which is available to authorized users.

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Autor: Emanuela Taioli - Annie Im - Xia Xu - Timothy D Veenstra - Gretchen Ahrendt - Seymour Garte


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