title: Mammary tumor development is directly inhibited by lifelong n-3 polyunsaturated fatty acids.
abstract: BACKGROUND
  Despite the advocacy that diet may be a significant contributor to cancer prevention, there is a lack of direct evidence from epidemiological and experimental studies to substantiate such claims. Experimental studies suggest that n-3 polyunsaturated fatty acids (n-3 PUFA) from marine oils may reduce breast cancer risk, however, findings are equivocal. Thus, in this study, novel transgenic mouse models were employed to provide, for the first time, direct evidence for an anti-cancer role of n-3 PUFA in mammary tumorigenesis.
  
  
  METHODS
  fat-1 Mice, which are capable of endogenous n-3 PUFA synthesis, were bred with mouse mammary tumor virus (MMTV)-neu(ndl)-YD5 mice, an aggressive breast cancer model. The resultant offspring, including novel hybrid progeny, were assessed for tumor onset, size and multiplicity as well as n-3 PUFA composition in mammary gland and tumor tissue. A complementary group of MMTV-neu(ndl)-YD5 mice were fed n-3 PUFA in the diet.
  
  
  RESULTS
  Mice expressing MMTV-neu(ndl)-YD5 and fat-1 displayed significant (P<.05) reductions in tumor volume (~30%) and multiplicity (~33%), as well as reduced n-6 PUFA and enriched n-3 PUFA in tumor phospholipids relative to MMTV-neu(ndl)-YD5 control mice. The effect observed in hybrid progeny was similarly observed in n-3 PUFA diet fed mice.
  
  
  CONCLUSIONS
  Using complementary genetic and conventional dietary approaches we provide, for the first time, unequivocal experimental evidence that n-3 PUFA is causally linked to tumor prevention.
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
authors.forename: Mira B
authors.initials: MB
authors.lastname: MacLennan
authors.forename: Shannon E
authors.initials: SE
authors.lastname: Clarke
authors.forename: Kate
authors.initials: K
authors.lastname: Perez
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Wood
authors.forename: William J
authors.initials: WJ
authors.lastname: Muller
authors.forename: Jing X
authors.initials: JX
authors.lastname: Kang
authors.forename: David W L
authors.initials: DW
authors.lastname: Ma
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D008297:Male; D008321:Mammary Glands, Animal / Q000737:chemistry; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000473:pathology* / Q000517:prevention & control*; D051379:Mice; D008822:Mice, Transgenic; D009929:Organ Size / Q000187:drug effects
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3