title: The association of breast mitogens with mammographic densities.
abstract: Radiologically dense breast tissue (mammographic density) is strongly associated with risk of breast cancer, but the biological basis for this association is unknown. In this study we have examined the association of circulating levels of hormones and growth factors with mammographic density. A total of 382 subjects, 193 premenopausal and 189 postmenopausal, without previous breast cancer or current hormone use, were selected in each of five categories of breast density from mammography units. Risk factor information, anthropometric measures, and blood samples were obtained, and oestradiol, progesterone, sex hormone binding globulin, growth hormone, insulin-like growth factor-I and its principal binding protein, and prolactin measured. Mammograms were digitised and measured using a computer-assisted method. After adjustment for other risk factors, we found in premenopausal women that serum insulin-like growth factor-I levels, and in postmenopausal women, serum levels of prolactin, were both significantly and positively associated with per cent density. Total oestradiol and progesterone levels were unrelated to per cent density in both groups. In postmenopausal women, free oestradiol (negatively), and sex hormone binding globulin (positively), were significantly related to per cent density. These data show an association between blood levels of breast mitogens and mammographic density, and suggest a biological basis for the associated risk of breast cancer.
authors.affiliation: Division of Epidemiology and Statistics, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario, Canada M5G 1K9. boyd@oci.utoronto.ca
authors.forename: N F
authors.initials: NF
authors.lastname: Boyd
authors.forename: J
authors.initials: J
authors.lastname: Stone
authors.forename: L J
authors.initials: LJ
authors.lastname: Martin
authors.forename: R
authors.initials: R
authors.lastname: Jong
authors.forename: E
authors.initials: E
authors.lastname: Fishell
authors.forename: M
authors.initials: M
authors.lastname: Yaffe
authors.forename: G
authors.initials: G
authors.lastname: Hammond
authors.forename: S
authors.initials: S
authors.lastname: Minkin
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008327:Mammography; D008875:Middle Aged; D008934:Mitogens / Q000378:metabolism; D017698:Postmenopause; D017697:Premenopause; D011374:Progesterone / Q000097:blood; D011388:Prolactin / Q000097:blood; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D018972:Insulin-Like Growth Factor Binding Protein 3; D008934:Mitogens; D012738:Sex Hormone-Binding Globulin; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D011388:Prolactin