Lu DL, et al. - Researchers used a cohort of the European Investigation into Cancer and Nutrition (EPIC) to determine the association between prediagnosis circulating 27-hydroxycholesterol (27HC; the first identified endogenous selective estrogen receptor modulator) and breast cancer risk in women. In this first prospective study, a lower risk of breast cancer in postmenopausal women was observed in relation to higher circulating 27HC.

Methods

• Using the well-characterized Heidelberg, Germany, cohort of the European Investigation into Cancer and Nutrition (EPIC) including 530 incident invasive breast cancer cases, each matched to up to two control participants (n=1,036), a nested case–control study was performed.
• Blood samples were collected at study recruitment and were analyzed for serum 27HC by using liquid chromatography–mass spectrometry (LC-MS).
• Using multivariable conditional logistic regression models, researchers quantified the link between circulating 27HC and breast cancer risk overall, by tumor hormone receptor status (ie estrogen and progesterone receptors), and by menopausal status at blood collection.
• All statistical tests were two-sided.

Results

• Findings revealed that 27HC was not related to breast cancer risk overall (relative risk [RR]_{Quartile4vsQuartile1 [Q4vsQ1]} = 0.90, 95% confidence interval [CI] = 0.66 to 1.22).
• On the basis of menopausal status at blood collection, the link between 27HC and breast cancer risk differed (P_het = .02), but not by age at diagnosis (P_het = .78).
• The association of higher serum 27HC levels with lower breast cancer risk was observed among women who were postmenopausal at blood collection (RR_Q4vsQ1 = 0.56, 95% CI = 0.36 to 0.87).
• Data showed no link between 27HC and breast cancer risk (RR_Q4vsQ1 = 1.33, 95% CI = 0.75 to 2.38) among women who were premenopausal at blood collection.