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BackgroundOvarian granulosa cells (GC) are essential for the development and maturation of a proper oocyte. GC are sensitive to endocrine disruptors, including bisphenol A (BPA) and its analogue bisphenol S (BPS), plasticisers present in everyday consumer products. BPA exhibits greater binding affinity for the membrane oestrogen receptor (GPER) than for the nuclear oestrogen receptors (ERα and ERβ). Here, we analysed the effects of BPA and BPS on the steroidogenesis of ovine GC in vitro, as well as their early mechanisms of action, the ovine being a relevant model to study human reproductive impairment. Disruption of GC steroidogenesis might alter oocyte quality and consequently fertility rate. In addition, we compared the effects of a specific GPER agonist (G-1) and antagonist (G-15) to those of BPA and BPS. Ewe GC were cultured with BPA or BPS (10 or 50 µM) or G-1 (1 µM) and/or G-15 (10 µM) for 48 h to study steroidogenesis.ResultsBoth BPA and BPS (10 µM) altered the secretion of progesterone, however, only BPS (10 µM) affected oestradiol secretion. RNA-seq was performed on GC after 1 h of culture with BPA or BPS (50 µM) or G-1 (10 µM), followed by real-time PCR analyses of differentially expressed genes after 12, 24 and 48 h of culture. The absence of induced GPER target genes showed that BPA and BPS did not activate GPER in GC after 1 h of treatment. These molecules exhibited mainly independent early mechanisms of action. Gene ontology analysis showed that after 1 h of treatment, BPA mainly disrupted the expression of the genes involved in metabolism and transcription, while BPS had a smaller effect and impaired cellular communications. BPA had a transient effect on the expression ofCHAC1(NOTCH signalling and oxidative balance),JUN(linked to MAPK pathway),NR4A1(oestradiol secretion inhibition),ARRDC4(endocytose of GPCR) andKLF10(cell growth, differentiation and apoptosis), while expression changes were maintained over time for the genesLSMEM1(linked to MAPK pathway),TXNIP(oxidative stress) andLIF(cell cycle regulation) after 12 and 48 h, respectively.ConclusionIn conclusion, although they exhibited similar effects, BPA and BPS impaired different molecular pathways in GC in vitro. New investigations will be necessary to follow the temporal changes of these genes over time, as well as the biological processes involved.

Bisphenol S (BPS) affects terminal folliculogenesis by impairing steroidogenesis in granulosa cells from different species. Nevertheless, limited data are available on its effects during basal folliculogenesis. In this study, we evaluate in vitro the effects of a long-term BPS exposure on a model of basal follicular development in a mono-ovulatory species. We cultured ovine preantral follicles (180–240 μm, n = 168) with BPS (0.1 μM (possible human exposure dose) or 10 μM (high dose)) and monitored antrum appearance and follicular survival and growth for 15 days. We measured hormonal secretions (oestradiol (at day 13 [D13]), progesterone and anti-Müllerian hormone [D15]) and expression of key follicular development and redox status genes (D15) in medium and whole follicles, respectively. BPS (0.1 µM) decreased oestradiol secretion compared with the control (−48.8%, p < 0.001), without significantly impairing antrum appearance, follicular survival and growth, anti-Müllerian hormone and progesterone secretion and target gene expression. Thus, BPS could also impair oestradiol secretion during basal folliculogenesis as it is the case during terminal folliculogenesis. It questions the use of BPS as a safe BPA substitute in the human environment. More studies are required to elucidate mechanisms of action of BPS and its effects throughout basal follicular development.

International audience; In mammalian ovaries, the theca layers of growing follicles are critical for maintaining their structural integrity and supporting androgen synthesis. Through combining the postnatal monitoring of ovaries by abdominal magnetic resonance imaging, endocrine profiling, hormonal analysis of the follicular fluid of growing follicles, and transcriptomic analysis of follicular theca cells, we provide evidence that the exposure of ovine fetuses to testosterone excess activates postnatal follicular growth and strongly affects the functions of follicular theca in adulthood. Prenatal exposure to testosterone impaired androgen synthesis in the small antral follicles of adults and affected the expression in their theca cells of a wide array of genes encoding extracellular matrix components, their membrane receptors, and signaling pathways. Most expression changes were uncorrelated with the concentrations of gonadotropins, steroids, and anti-Müllerian hormone in the recent hormonal environment of theca cells, suggesting that these changes rather result from the long-term developmental effects of testosterone on theca cell precursors in fetal ovaries. Disruptions of the extracellular matrix structure and signaling in the follicular theca and ovarian cortex can explain the acceleration of follicle growth through altering the stiffness of ovarian tissue. We propose that these mechanisms participate in the etiology of the polycystic ovarian syndrome, a major reproductive pathology in woman.

Study question Do plastic laboratory consumables and cell culture media used in human ART contain bisphenols? Summary answer Human embryo development media contained bisphenols close to the nanomolar concentration range while no release of bisphenols by plastic consumables was detected under routine conditions. What is known already The deleterious effect of the endocrine disruptor bisphenol A (BPA) on female fertility raised concerns regarding ART outcome. BPA was detected neither in media nor in the majority of plastic consumables used in ART, however it might have already been replaced by its structural analogs, including bisphenol S (BPS). Study design, size, duration Seventeen plastic consumables and 18 cell culture and ART media were assessed for the presence of bisphenols. Participants/materials, setting, methods Ten different bisphenols (bisphenol A, S, AF, AP, B, C, E, F, P, and Z) were measured using an isotopic dilution according to an on-line solid phase extraction / liquid chromatography/mass spectrometry method. Main results and the role of chance While all the plastic consumables of this study did contain bisphenols, none of them did release bisphenols under routine conditions. Moreover, 16 of the 18 cell culture and ART media assessed contained bisphenols, including 8 among the 10 media used in human ART. Five human ART media exhibited bisphenol concentrations higher than 0.8 nM and reached up to 3.2 nM (799 ng/L). Limitations, reasons for caution Further studies are required to investigate a greater number of ART media to identify less potentially harmful ones, in terms of bisphenol content. Wider implications of the findings As BPS has already been reported to impair oocyte quality at nanomolar concentrations, its presence in ART media, at a similar concentration range, could contribute to a decrease in the ART success rate. Thus far, there has been no regulation of these compounds in the ART context. Trial registration number Not applicable

Bisphenols, plasticisers used in food containers, can transfer to food. Bisphenol A (BPA) has been described as an endocrine disruptor and consequently banned from the food industry in several countries. It was replaced by a structural analogue, Bisphenol S (BPS). BPA action on the steroidogenesis is one of the mechanisms underlying its adverse effects on the efficiency of female reproduction. This study aimed to determine whether BPS is a safe alternative to BPA regarding GC functions. Antral follicles (2–6 mm), of approximatively 1000 adult ewe ovaries, were aspired and GC purified. For 48 h, ovine GC were treated with BPA or BPS (from 1 nM to 200 µM) and the effects on cell viability, proliferation, steroid production, steroidogenic enzyme expression and signalling pathways were investigated. Dosages at and greater than 100 μM BPA and 10 µM BPS decreased progesterone secretion by 39% (P P = 0.040), respectively. BPA and BPS 10 μM and previously mentioned concentrations increased oestradiol secretion two-fold (P P = 0.082, respectively). Only 100 µM BPA induced a decrease (P ESR1 and ESR2 gene expression, effects that were not observed with BPS. BPA and BPS altered steroidogenesis of ovine GC. Thus, BPS does not appear to be a safe alternative for BPA. Further investigations are required to elucidate BPA and BPS mechanisms of action.

The objective of this study was to determine whether fish oil supplement has an effect on adipose tissue lipid profiles and gene expression in postpartum dairy cows. Holstein cows were supplemented with either long-chain n-3 polyunsaturated fatty acid (PUFA; protected fish oil) or control PUFA (n-6; toasted soybeans) for 2mo after calving (n=23 per diet). These cows showed no difference in milk production or metabolic parameters, but exhibited a tendency toward a decrease in early embryo mortality rate after artificial insemination. We hypothesized that, in addition to this effect, modifications in adipose tissue (AT) gene expression and lipid profiles would occur in response to diet. Subcutaneous AT samples were thus collected from the dewlaps of n-3 and n-6 dairy cows at 1mo antepartum, and 1wk, 2mo, and 5mo postpartum for the analysis of lipids and gene expression. Lipid profiles were obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in both positive and negative modes. We found 37 lipid species in the 200 to 1,200 m/z range, which differed between the n-3 and control groups, suggesting that the n-3 supplement affected the lipid composition through the enrichment of lipids integrating long-chain PUFA from fish oil sources: eicosapentaenoic and docosahexaenoic acid. Moreover, a decrease in triacylglycerolipids was observed in AT of n-3 supplemented cows. The expression of 44 genes involved in fatty acid metabolism and the adipokine system was assessed by real-time reverse-transcription PCR. Hierarchical clustering, according to either postpartum stage or diet, enabled us to group genes exhibiting similar kinetic properties during lactation or by those that varied in similar ways after n-3 supplementation, respectively. Among the genes exhibiting a dietary effect, FABP4, LIPE, CD36, and PLIN1 were overexpressed in n-3 AT samples compared with the control, suggesting an increase in lipolysis due to n-3 supplementation, which was reflected on lipolytic activity at the protein level (i.e., protein expression of fatty acid binding protein 4, phosphorylated perilipin 1, and phosphorylated hormone-sensitive lipase). This increase in lipolysis is relevant to the decrease in triglycerides observed in these samples. Gene expression analyses between n-3 and control AT samples also suggested that the n-3 diet could modulate the secretory functions of AT, possibly by affecting adipokine expression; however, this has to be confirmed at the protein level.

Bisphenol S (BPS) is a structural analog of the endocrine disruptor bisphenol A (BPA), it is the main BPA replacement in the plastics industry. Previous studies have shown that BPA and BPS exhibit similar effects on reproduction in fish and rodent species. BPS reportedly alters steroidogenesis in bovine granulosa cells. Luteinised granulosa cells collected from 59 women who were undergoing an in vitro fertilization procedure were cultured for 48 h in the presence or absence of BPS (10 nM, 100 nM, 1 &micro, M, 10 &micro, M or 50 &micro, M). BPS exposure was investigated by assessing follicular fluids from these 59 women for their BPS content. Culture medium, cells, total messenger RNA (mRNA) and total protein extracted from the luteinised granulosa cells were examined for oestradiol and progesterone secretion, cellular proliferation, viability, gene expression, steroidogenic enzyme expression and cell signaling. BPS was measured in follicular fluids using mass spectrometry. Exposure of granulosa cells to 10 or 50 &micro, M BPS for 48 h induced a 16% (p = 0.0059) and 64% (p &lt, 0.0001) decrease, respectively, in progesterone secretion, 50 &micro, M BPS decreased oestradiol secretion by 46% (p &lt, 0.0001). Ten &micro, M BPS also tended to reduce CYP11A1 protein expression by 37% (p = 0.0947) without affecting HSD3B1 and CYP19A1 expression. Fifty &micro, M BPS increased ERRg expression. Environmental levels of BPS (nanomolar range) did not induce changes in steroidogenesis in human granulosa cells. The effects of BPS were observed after only 48 h of BPS exposure. These acute effects might be similar to chronic effects of physiological BPS levels.

Remerciements : INRA, UMR1331 ToxAlim Toxicologie Alimentaire; Plateforme GENOTOUL, Toulouse; Gene loss is one of the main drivers in the evolution of genomes and species. The demonstration that a gene has been lost by pseudogenisation is truly complete when one finds the pseudogene in the orthologous genomic region with respect to active genes in other species. In some cases, the identification of such orthologous loci is not possible because of chromosomal rearrangements or if the gene of interest has not yet been sequenced. This question is particularly important in the case of birds because the genomes of avian species possess only about 15,000 predicted genes, in comparison with 20,000 in mammals. Yet, gene loss raises the question of which functions are affected by the changes in gene counts. We describe a systematic approach that makes it possible to demonstrate gene loss in the chicken genome even if a pseudogene has not been found. By using phylogenetic and synteny analysis in vertebrates, genome-wide comparisons between the chicken genome and ESTs, RNAseq data analysis, statistical analysis of the chicken genome, and Radiation Hybrid mapping, we show that resistin, TNFα and PAI-1 (SERPINE1), three genes encoding adipokines inhibiting insulin sensitivity, have been lost in chicken as well as zebra finch genomes. Moreover, omentin, a gene encoding an adipokine that enhances insulin sensitivity, has also been lost in the chicken genome. Overall, only one adipokine inhibiting insulin sensitivity, and five adipokines enhancing insulin sensitivity, are still present in the chicken genome. These genetic differences between mammals and chicken, given the functions of the genes in mammals, would have dramatic consequences on chicken endocrinology, leading to novel equilibriums especially in the regulation of energy metabolism, insulin sensitivity, as well as appetite and reproduction.

In this study, we systematically compared the morphological, functional and molecular characteristics of granulosa cells and oocytes obtained by a three-dimensional

Les derives diene-conjugues de l’acide linoleique correspondent a une famille d’isomeres geometriques et positionnels de l’acide linoleique (isomeres diene-conjugues) collectivement denommes CLA (pour conjugated linoleic acid). Ce groupe d’acides gras, present dans les aliments d’origine animale comme la viande de ruminants ou dans certains produits laitiers [1], est egalement genere au cours de la cuisson [2], ainsi que sous l’action de la flore bacterienne intestinale [3]. L’isomere principal est le 9-cis,11-trans CLA. Cet isomere resulte aussi de la conversion endogene de l’acide vaccenique trans-11 18 :1, egalement present dans le lait. Les derives conjugues de l’acide linoleique (CLA) semblent avoir des proprietes inhibitrices de la cancerogenese, notamment mammaire. L’utilisation de differentes especes animales (souris, rates, hamsters), de diverses lignees cellulaires cancereuses, et de plusieurs modeles de cancerogenese (cancers chimio-induits avec des cancerigenes directs ou indirects, tumeurs transplantees) ont permis de confirmer le role protecteur des CLA en cancerogenese pour differents sites : peau [2], estomac [4], pancreas [5], foie [6], poumon [7], glandes mammaires [8-11] et colique [11-15]. Il a ete rapporte un effet inhibiteur des CLA aux differentes phases : initiation [9, 16, 17], promotion et croissance tumorales [8, 16], formation de metastases [18, 19]. Dans le modele de tumeurs mammaires chimio-induites, des rates prepuberes dont le regime etait supplemente en CLA avant l’initiation par un agent cancerigene (dimethylbenz(a)anthracene ou N-nitroso-N-methyluree), ont developpe significativement moins de tumeurs que les rates temoins (47 %) [9, 20], suggerant que la presence de CLA dans les tissus mammaires les rendraient moins sensibles a l’initiation ulterieure par un agent cancerigene. De meme, si la supplementation en CLA etait realisee apres l’initiation par un agent cancerigene pendant 20 semaines, les rates developpent significativement moins de tumeurs que les rates du lot temoin (32 a 60 % de tumeurs en moins) [8, 9]. Ces effets inhibiteurs de la promotion tumorale sont independants de la nature de l’agent cancerigene utilise ou des lipides (nature et quantite) administres dans le regime [21, 22]. L’apport de CLA dans la diete sous la forme d’acides gras libres semble avoir un effet similaire a celui des

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.

En France, comme dans la plupart des pays occidentaux, le cancer du sein est la première cause de mortalité, avec un nombre annuel de décès proche de 10 000. Chez les femmes, le cancer du sein est celui dont le taux d’incidence est le plus élevé dans la plupart des pays occidentaux. En France, il y a approximativement 35 000 nouveaux cas chaque année. Le taux d’incidence est de 80 pour 100 000 femmes/an. Il existe une disparité géographique dans les taux d’incidence du cancer du sein. Ils sont élevés dans tous les pays développés, à l’exception du Japon et de la Chine. Ajusté sur l’âge, il est le plus élevé aux États-Unis, et le plus bas en Chine, en Inde, au Japon. La France se situe à une position intermédiaire en Europe. L’incidence du cancer du sein est globalement plus faible dans les pays du Sud de l’Europe. Cette disparité géographique ne peut pas être expliquée uniquement par les facteurs génétiques. L’étude des populations migrantes, dont les taux d’incidence du cancer du sein se modifient pour atteindre celui du pays dans lequel elles migrent, a permis de mettre en évidence le rôle des facteurs environnementaux dans l’apparition du cancer du sein. Parmi ceux-là, la part de l’alimentation est estimée à environ 35 % (entre 20 à 60 %, en fonction du site du cancer) [1]. Il existe donc un réel potentiel de prévention du cancer du sein, sous réserve que les aliments protecteurs soient mis en évidence et que les nutriments responsables de ces effets protecteurs soient individualisés.

Background Adiponectin is an adipokine, mainly produced by adipose tissue. It regulates several reproductive processes. The protein expression of the adiponectin system (adiponectin, its receptors, AdipoR1 and AdipoR2 and the APPL1 adaptor) in bovine ovary and its role on ovarian cells and embryo, remain however to be determined. Methods Here, we identified the adiponectin system in bovine ovarian cells and embryo using RT-PCR, immunoblotting and immunohistochemistry. Furthermore, we investigated in vitro the effects of recombinant human adiponectin (10 micro g/mL) on proliferation of granulosa cells (GC) measured by [3H] thymidine incorporation, progesterone and estradiol secretions measured by radioimmunoassay in the culture medium of GC, nuclear oocyte maturation and early embryo development. Results We show that the mRNAs and proteins for the adiponectin system are present in bovine ovary (small and large follicles and corpus luteum) and embryo. Adiponectin, AdipoR1 and AdipoR2 were more precisely localized in oocyte, GC and theca cells. Adiponectin increased IGF-1 10(-8) M-induced GC proliferation (P < 0.01) but not basal or insulin 10(-8) M-induced proliferation. Additionally, adiponectin decreased insulin 10(-8) M-induced, but not basal or IGF-1 10(-8) M-induced secretions of progesterone (P < 0.01) and estradiol (P < 0.05) by GC. This decrease in insulin-induced steroidogenesis was associated with a decrease in ERK1/2 MAPK phosphorylation in GC pre-treated with adiponectin. Finally, addition of adiponectin during in vitro maturation affected neither the percentage of oocyte in metaphase-II nor 48-h cleavage and blastocyst day 8 rates. Conclusions In bovine species, adiponectin decreased insulin-induced steroidogenesis and increased IGF-1-induced proliferation of cultured GC through a potential involvement of ERK1/2 MAPK pathway, whereas it did not modify oocyte maturation and embryo development in vitro.

Evidence of a protective effect of fruit and vegetable intake on breast cancer risk is inconsistent. Epidemiologic cohort studies based on blood carotenoid intakes as biomarkers of consumption of fruits and vegetable in individuals are still scare and findings are discrepant. The study population included women in the E3N Study, the large French component of the European Prospective Investigation into Cancer and Nutrition (EPIC). During an average of 7 years follow-up, 366 cases of incident invasive breast cancer (84 premenopausal women and 282 postmenopausal women) among 19,934 women who completed a dietary questionnaire and had available blood samples at baseline (1995-1998) were included in the study. Controls were randomly matched on age, menopausal status at blood collection, fasting status at blood collection, date and collection center. Serum carotenoids, tocopherols and retinol concentrations were assessed by high pressure liquid chromatography. Odds ratios for breast cancer risk adjusted for established breast cancer risk factors were calculated by quintile of serum micronutrient concentrations. No significant associations between breast cancer risk and serum carotenoids (highest versus lowest quintile, odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.47-1.16, p for trend 0.38), tocopherols (OR = 0.68, 95% CI = 0.41-1.10, p for trend 0.26) and retinol (OR = 0.85, 95% CI = 0.53-1.35, p for trend 0.34) were found. Our findings did not support the hypothesis that lipophilic antioxidant micronutrients found in fruits and vegetables protect against breast cancer, at least in postmenopausal women.

The association between the level of conjugated linoleic acid (CLA) in breast adipose tissue at the time of diagnosis and the subsequent development of metastasis was examined in a cohort of 209 patients presenting with an initially localized breast cancer. CLA level in breast adipose tissue was used as a qualitative biomarker of its past dietary intake. Biopsies of adipose tissue were obtained at the time of initial surgery. A CLA-enriched fraction was prepared by high performance liquid chromatography and CLA measured as a percentage of total fatty acids, using capillary gas chromatography. Mean CLA level was low (0.44% of total fatty acids) and the range between patients was narrow (0.19-0.85). With a median follow-up time of 7.5 yr, 45 patients developed metastases. A Cox proportional hazard regression model was used to identify prognostic factors. We did not find any significant association between CLA level in adipose fat and either the prognostic factor (tumor size, nodal status, histoprognostic grade, mitotic index, and estrogen or progesterone receptors) or the risk of metastasis or death. We concluded that CLA are unlikely to be involved in survivorship. However, the hypothesis that a higher intake of CLA might have a protective effect on the risk of metastasis cannot be ruled out from these data, since the level of CLA in breast cancer patients' adipose tissue is likely to be too low and the range of CLA distribution too narrow for any protection to be detectable.

Oocyte maturation relies on energy from different nutrients, including fatty acids (FA). Cumulus cells (CC) are metabolically coupled with enclosed oocyte and active FA metabolism occurs in both compartments. Excess of lipids in oocyte environment alters its developmental competence. Lipid droplets (LD), mainly composed of triacylglycerides (TG), are formed inside of CC and in oocyte to store lipids. Liberation of free FA from TG requires lipolysis, which is catalyzed by lipases and involves FA-binding proteins (FABP) and perilipins (PLIN), which interact at the surface of LD as shown in lipogenic tissues. The objective was to elucidate the main factors involved in lipolysis in bovine cumulus-oocyte complex (COC) during oocyte maturation. Gene expression before and after maturation was analysed in CC by microarray hybridization and validated by real time RT-PCR; proteins were detected by Western blot and immunofluorescence. For statistics, ANOVA and Mann-Whitney (M-W) tests were used. In CC, adipose triglyceride lipase PNPLA2, lipoprotein lipase LPL, and monoacylglycerol lipase ABHD6 showed the highest mRNA expression level among 7 detected lipases. Both PLIN5 and PLIN2 were the most abundant perilipins, and among 8 FA-binding proteins, FABP3 and FABP5 were predominant. During in vitro maturation (IVM), expression of most of these genes increased at 6 h of IVM (P

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.

National audience