Biomarkers Of Fatty Acids And Breast Cancer Risk, Overall And By Hormonal Receptor Status: Report From The European Prospective Investigation Into Cancer And Nutrition (EPIC) Study

Veronique CHAJES, International Agency for Research on Cancer, France
ROMIEU I. 1 , ASSI N. 1 , BIESSY C. 1 , FERRARI P. 1 , RINALDI S. 1 , COLLIN M. 2 , SLIMANI N. 1

1 Nutrition and Metabolism, International Agency for Research on Cancer, Lyon, France
2 Plateforme Lipidomique, Institut Gustave Roussy, Villejuif, France

Purpose. Intakes of specific fatty acids have been postulated to impact breast cancer (BC) risk but epidemiological data based on biomarkers of exposure and metabolism are scarce. The objective of this study was to assess the association between biomarkers of fatty acids and BC risk in a large case-control study nested within the EPIC study.
Methods. Fatty acids were measured by gas chromatography in plasma phospholipids from 2,982 BC cases matched to 2,982 controls for center, age, menopausal status, exogenous hormone use, time of the day at blood collection, fasting status, and phase of the menstrual cycle. Conditional logistic regression models adjusted for date at blood collection, years of education, body mass index, height, menopausal hormone use at baseline, alcohol, age at first birth and parity combined, energy intake, and family history of BC were used to estimate odds ratios by quartiles of fatty acids. Subgroup analyses were performed by menopausal status and estrogen receptor (ER, 1,649 ER+, 398 ER-) and progesterone receptor (PR, 1,150 PR+, 579 PR-) expression in tumors.
Results. Overall, increased risk of BC was associated with increasing ratio of cis-monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) (odds ratio (OR)=1.28; 95% confidence interval (CI)=1.07-1.54; p for trend =0.002), as biomarkers of endogenous synthesis of MUFA. Stratification by menopausal status revealed no substantial difference. Increased risk of ER- BC was specifically and statistically significantly associated with increasing levels of industrial trans fatty acids (ITFA) (OR=2.01; 95% CI=1.03-3.90; p for trend=0.047), while no association remained with ER+ BC (OR=82; 95% CI=0.62-1.10; p for trend=0.102) (P-heterogeneity=0.015).
Conclusions. These findings suggest that increased endogenous synthesis of MUFA may increase BC risk, independently of menopausal or hormonal receptor status. Dietary ITFA may specifically increase ER- BC development.
Funding sources. Ligue Nationale contre le Cancer, Fondation de France, WCRF.