title: Effects of soy protein and soy phytochemicals on mammary tumor development in female transgenic mice overexpressing human pituitary growth hormone.
abstract: The objective of this study was to determine the effect of soy-based diets on mammary tumors in female cancer- prone mice. Transgenic virgin female mice expressing human pituitary growth hormone and their respective phenotypically normal littermates were fed a diet containing either casein (C), low-isoflavone soy protein (LIS), or high-isoflavone soy protein (HIS). Indices of tumor development were measured throughout the study. Both days from birth until death and days on diet until death were increased [by 20% (P = .01) and 19% (P = .02), respectively] in the LIS group when compared with the C group. Both intervals were increased also (by 16% and 17%, respectively; P < .05) in the HIS group when compared with the C group. Days from birth to first tumor were increased by 7% (P < .05), as was days on diet to first tumor by 5% (P < .05), in the LIS group when compared with the C group. First-onset number of tumors was decreased (P = .02) by 41% and 34% in the LIS and C groups, respectively, when compared with the HIS group. Final onset of tumors was decreased (P < .05) by 44% and 9% in the LIS and HIS groups, respectively, when compared with the C group. Total area of final tumors was decreased (P < .05) by 30% in the LIS group when compared with the C group. Taken cumulatively, these data suggest that a diet rich in soy protein may provide protective benefits regarding tumor development in female cancer-prone mice. Furthermore, some bioactive compounds in the HIS diet appeared to confound the soy protein-induced beneficial effects.
authors.affiliation: Departments of Animal Science, Food & Nutrition, Southern Illinois University, Carbondale, IL 62901-4317, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hickey
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bartke
authors.forename: Todd
authors.initials: T
authors.lastname: Winters
authors.forename: Nancy
authors.initials: N
authors.lastname: Henry
authors.forename: William
authors.initials: W
authors.lastname: Banz
mesh_terms: D000818:Animals; D004032:Diet; D005260:Female; D015870:Gene Expression; D020022:Genetic Predisposition to Disease; D013006:Growth Hormone / Q000235:genetics*; D007529:Isoflavones / Q000008:administration & dosage*; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000517:prevention & control*; D051379:Mice; D008822:Mice, Transgenic; D030262:Soybean Proteins / Q000494:pharmacology*; D013025:Glycine max / Q000737:chemistry*
chemical_list: D007529:Isoflavones; D030262:Soybean Proteins; D013006:Growth Hormone