Mouse Anti-Estrone 3 glucuronide monoclonal antibody, clone IN768

Background Epidemiological studies have provided strong evidence for a role of endogenous sex steroids in the etiology of breast cancer. Our aim was to identify common variants in genes involved in sex steroid synthesis or metabolism that are associated with hormone levels and the risk of breast cancer in premenopausal women. Methods We measured urinary levels of estrone glucuronide (E1G) using a protocol specifically developed to account for cyclic variation in hormone levels during the menstrual cycle in 729 healthy premenopausal women. We genotyped 642 single-nucleotide polymorphisms (SNPs) in these women; a single SNP, rs10273424, was further tested for association with the risk of breast cancer using data from 10 551 breast cancer case patients and 17 535 control subjects. All statistical tests were two-sided. Results rs10273424, which maps approximately 50 kb centromeric to the cytochrome P450 3A (CYP3A) gene cluster at chromosome 7q22.1, was associated with a 21.8% reduction in E1G levels (95% confidence interval [CI] = 27.8% to 15.3% reduction; P = 2.7 x 10(-9)) and a modest reduction in the risk of breast cancer in case patients who were diagnosed at or before age 50 years (odds ratio [OR] = 0.91, 95% CI = 0.83 to 0.99; P = .03) but not in those diagnosed after age 50 years (OR = 1.01, 95% CI = 0.93 to 1.10; P = .82). Conclusions Genetic variation in noncoding sequences flanking the CYP3A locus contributes to variance in premenopausal E1G levels and is associated with the risk of breast cancer in younger patients. This association may have wider implications given that the most predominantly expressed CYP3A gene, CYP3A4, is responsible for metabolism of endogenous and exogenous hormones and hormonal agents used in the treatment of breast cancer.

Objective: The purpose of this study was to develop an integrative assessment of pituitary follicle-stimulating hormone (FSH) secretion and to validate these measurements in a population of perimenopausal (PERI) and postmenopausal (POST) women. Design: In this cross-sectional study, 170 POST and 20 PERI women collected first-void morning urine samples and had a single blood sample drawn on the same day. For comparison, I I midreproductive-aged women had urine samples collected for one menstrual cycle. In addition, one 48.5-year-old woman collected daily urine samples for 4 consecutive years during her menopausal transition. Urine samples were assayed for estrone glucuronide (E(1)G) and pregnanediol-3-glucuronide (PdG) and were normalized to creatinine. An ELISA assay was developed for measurement of the free beta-FSH subunit in urine. Results: Mean age (+/- SD) of the PERI and POST women were 48.1 +/- 3.0 and, 52.8 +/- 4.1 years, respectively. Mean serum FSH levels were 9.5 +/- 5.8 and 79.3 +/- 32 IU/L (P < 0.00 1) in the PERI and POST women. Mean urinary beta-FSH/Cr for the PERI were 1.8 +/- 1.2 ng/mg; for the POST, 9.3 +/- 4.5 ng/mg (P < 0.001). Mean estradiol, E(1)G/Cr, and PdG/Cr levels were also significantly different between the two groups. There was a high correlation between serum FSH and urinary beta-FSH/Cr for the PERI (r = 0.584, P = 0.007) and POST (r = 0.54, P < 0.001), with minimal overlap in the urinary beta-FSH/Cr levels between the PERI and POST groups. A significant correlation between PdG/Cr and urinary beta-FSH/Cr was observed for POST (r = 0.58 1, P = 0.002). No correlation was seen between urinary beta-FSH/Cr and E(1)G/Cr or estradiol levels. In the perimenopausal participant, who collected 4 years of daily urine samples, urinary beta-FSH/Cr levels progressively increased during the follicular phase and, by the fourth year, there were persistent, almost tonically high elevations of beta-FSH/Cr in the urine. Conclusions: Urinary beta-FSH subunit measurements are a useful marker for monitoring ovarian function during the menopausal transition. Urinary free beta-FSH subunit concentrations reflect pituitary FSH secretion and serve as a biomarker for ovarian reserve.