title: Milk inhibits the regression of 7,12-dimethylbenz(a)anthracene-induced mammary tumors in ovariectomized rats.
abstract: Epidemiological studies have yielded inconsistent results regarding the relation between the milk consumption and breast cancer risk. In this study, rats were induced mammary tumors by 7,12-dimethylbenz(a)anthracene. When tumors developed to acceptable levels, rats were placed into 1 of 3 treatment groups. Those in the negative control group and the milk group were ovariectomized, whereas those in the positive control group were sham operated. After grouping, tumor incidence remained 100%, and tumor number and volume increased in the positive control group. However, tumors in the 2 ovariectomized groups regressed. Compared with the negative control group, tumor incidence and tumor number and volume per rat in the milk group became significantly higher from Week 6 and Week 4, respectively. Insulin-like growth factor-I levels were borderline significantly higher in the milk group than in the negative control group at autopsy. Although plasma 17beta-estradiol levels did not differ significantly, estrogenicity was found in the milk group because uterine weight was significantly heavier in the milk group than in the negative control group. In conclusion, commercial milk inhibited the regression of carcinogen-induced mammary tumors in ovariectomized rats.
authors.affiliation: School of Radiation Medicine and Public Health, Soochow University, Suzhou, China. qinliqiang0326@yahoo.com.cn
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Qin
authors.forename: Jia-Ying
authors.initials: JY
authors.lastname: Xu
authors.forename: Hideo
authors.initials: H
authors.lastname: Tezuka
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Wang
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hoshi
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002273:Carcinogens; D004958:Estradiol / Q000097:blood; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D015674:Mammary Neoplasms, Animal / Q000139:chemically induced / Q000453:epidemiology / Q000473:pathology*; D008892:Milk / Q000009:adverse effects* / Q000737:chemistry; D009929:Organ Size; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000473:pathology
chemical_list: D002273:Carcinogens; D004958:Estradiol; D015127:9,10-Dimethyl-1,2-benzanthracene; D007334:Insulin-Like Growth Factor I