title: The association of measured breast tissue characteristics with mammographic density and other risk factors for breast cancer.
abstract: BACKGROUND
  We have examined the relationships between the measured properties of breast tissue and mammographic density and other risk factors for breast cancer, using breast tissue obtained at forensic autopsy and not selected for the presence of abnormalities.
  
  
  METHODS
  We used randomly selected tissue blocks taken from breast tissue slices obtained by s.c. mastectomy at the time of forensic autopsy to measure histologic features using quantitative microscopy. The proportions of the biopsy occupied by cells (estimated by nuclear area), glandular structures, and collagen were determined. These measurements were examined in relation to the percent density in the faxitron image of the tissue slice from which the biopsy was taken and other risk factors for breast cancer.
  
  
  RESULTS
  The percent mammographic density was associated with the proportion of the area of the biopsy occupied by nuclei, both epithelial and nonepithelial, and by collagen and the area of glandular structures. Several other risk factors for breast cancer, notably body weight, parity, and number of births, and menopausal status, that are associated with variations in mammographic density, were also associated with differences in one or more of these tissue features.
  
  
  CONCLUSIONS
  All risk factors for breast cancer must ultimately exert their influence by an effect on the breast, and these findings suggest that, for some risk factors, this influence includes an effect on the number of cells and the quantity of collagen.
authors.affiliation: Division of Epidemiology and Statistics, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario, Canada M5G 2M9.
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.forename: Limei
authors.initials: L
authors.lastname: Sun
authors.forename: Naomi
authors.initials: N
authors.lastname: Miller
authors.forename: Trudey
authors.initials: T
authors.lastname: Nicklee
authors.forename: Jennifer
authors.initials: J
authors.lastname: Woo
authors.forename: Lee
authors.initials: L
authors.lastname: Hulse-Smith
authors.forename: Ming-Sound
authors.initials: MS
authors.lastname: Tsao
authors.forename: Rama
authors.initials: R
authors.lastname: Khokha
authors.forename: Lisa
authors.initials: L
authors.lastname: Martin
authors.forename: Norman
authors.initials: N
authors.lastname: Boyd
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D002452:Cell Count; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D003094:Collagen