N-3 and N-6 fatty acids in breast adipose tissue and relative risk of breast cancer in a case-control study in Tours, France

Authors

  • Virginie Maillard,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Philippe Bougnoux,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Pietro Ferrari,

    1. Unit of Nutrition and Cancer, International Agency for Research on Cancer, Lyon, France
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  • Marie-Lise Jourdan,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Michelle Pinault,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Flore Lavillonnière,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Gilles Body,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Olivier Le Floch,

    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
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  • Véronique Chajès

    Corresponding author
    1. Laboratoire de Biologie des Tumeurs, Clinique d'Oncologie-Radiothérapie, Service de Gynécologie-Obstétrique, E.A. 2103, Unité de Recherche Associée Université-INRA, CHU, Tours, France
    • Nutrition, Croissance et Cancer, UPRES-EA 2103, Université F. Rabelais, 2, bis bd Tonnellé, F-37032 Tours, France
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    • Fax: +33-0-247-47-62-26


Abstract

Experimental studies have indicated that n-3 fatty acids, including alpha-linolenic acid (18:3 n-3) and long-chain n-3 polyunsaturated fatty acids inhibit mammary tumor growth and metastasis. Earlier epidemiological studies have given inconclusive results about a potential protective effect of dietary n-3 polyunsaturated fatty acids on breast cancer risk, possibly because of methodological issues inherent to nutritional epidemiology. To evaluate the hypothesis that n-3 fatty acids protect against breast cancer, we examined the fatty acid composition in adipose tissue from 241 patients with invasive, nonmetastatic breast carcinoma and from 88 patients with benign breast disease, in a case-control study in Tours, central France. Fatty acid composition in breast adipose tissue was used as a qualitative biomarker of past dietary intake of fatty acids. Biopsies of adipose tissue were obtained at the time of surgery. Individual fatty acids were measured as a percentage of total fatty acids, using capillary gas chromatography. Unconditional logistic regression modeling was used to obtain odds ratio estimates while adjusting for age, height, menopausal status and body mass index. We found inverse associations between breast cancer-risk and n-3 fatty acid levels in breast adipose tissue. Women in the highest tertile of alpha-linolenic acid (18:3 n-3) had an odds ratio of 0.39 (95% confidence intervals [CI] = 0.19–0.78) compared to women in the lowest tertile (trend p = 0.01). In a similar way, women in the highest tertile of docosahexaenoic acid (22:6 n-3) had an odds ratio of 0.31 (95% CI = 0.13-0.75) compared to women in the lowest tertile (trend p = 0.016). Women in the highest tertile of the long-chain n-3/total n-6 ratio had an odds ratio of 0.33 (95% confidence interval = 0.17–0.66) compared to women in the lowest tertile (trend p = 0.0002). In conclusion, our data based on fatty acids levels in breast adipose tissue suggest a protective effect of n-3 fatty acids on breast cancer risk and support the hypothesis that the balance between n-3 and n-6 fatty acids plays a role in breast cancer. © 2001 Wiley-Liss, Inc.

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