title: Mammographic density and epithelial histopathologic markers.
abstract: BACKGROUND
  We explored the association of mammographic density, a breast cancer risk factor, with hormonal and proliferation markers in benign tissue from tumor blocks of pre-and postmenopausal breast cancer cases.
  
  
  METHODS
  Breast cancer cases were recruited from a case-control study on breast density. Mammographic density was assessed on digitized prediagnostic mammograms using a computer-assisted method. For 279 participants of the original study, we obtained tumor blocks and prepared tissue microarrays (TMA), but benign tissue cores were only available for 159 women. The TMAs were immunostained for estrogen receptor alpha (ERalpha) and beta (ERbeta), progesterone receptor (PR), HER2/neu, Ki-67, and Proliferating Cell Nuclear Antigen (PCNA). We applied general linear models to compute breast density according to marker expression.
  
  
  RESULTS
  A substantial proportion of the samples were in the low or no staining categories. None of the results was statistically significant, but women with PR and ERbeta staining had 3.4% and 2.4% higher percent density. The respective values for Caucasians were 5.7% and 11.6% but less in Japanese women (3.5% and -1.1%). Percent density was 3.4% higher in women with any Ki-67 staining and 2.2% in those with positive PCNA staining.
  
  
  CONCLUSIONS
  This study detected little evidence for an association between mammographic density and expression of steroid receptors and proliferation markers in breast tissue, but it illustrated the problems of locating tumor blocks and benign breast tissue samples for epidemiologic research. Given the suggestive findings, future studies examining estrogen effects in tissue, cell proliferation, and density in the breast may be informative.
authors.affiliation: Cancer Research Center, University of Hawaii, Honolulu, HI, USA. m.verheus@nki.nl
authors.forename: Martijn
authors.initials: M
authors.lastname: Verheus
authors.forename: Gertraud
authors.initials: G
authors.lastname: Maskarinec
authors.forename: Eva
authors.initials: E
authors.lastname: Erber
authors.forename: Jana S
authors.initials: JS
authors.lastname: Steude
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Killeen
authors.forename: Brenda Y
authors.initials: BY
authors.lastname: Hernandez
authors.forename: J Mark
authors.initials: JM
authors.lastname: Cline
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D049109:Cell Proliferation; D047628:Estrogen Receptor alpha / Q000096:biosynthesis; D047629:Estrogen Receptor beta / Q000096:biosynthesis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008327:Mammography / Q000379:methods*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D017698:Postmenopause; D017697:Premenopause; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D011980:Receptors, Progesterone / Q000096:biosynthesis
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D018809:Proliferating Cell Nuclear Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011980:Receptors, Progesterone; C506487:ESR1 protein, human; C508053:ERBB2 protein, human