Breast Cancer Research and Treatment

, Volume 125, Issue 1, pp 243–252 | Cite as

Aromatase immunoreactivity is increased in mammographically dense regions of the breast

  • Celine M. VachonEmail author
  • Hironobu Sasano
  • Karthik Ghosh
  • Kathleen R. Brandt
  • David A. Watson
  • Carol Reynolds
  • Wilma L. Lingle
  • Paul E. Goss
  • Rong Li
  • Sarah E. Aiyar
  • Christopher G. Scott
  • V. Shane Pankratz
  • Richard J. Santen
  • James N. Ingle


Mammographic breast density (MBD) is one of the strongest risk factors for breast cancer. Unfortunately, the biologic basis underlying this association is unknown. This study compared aromatase expression or immunoreactivity (IR) in core biopsies from mammographically dense versus non-dense regions of the breast to examine whether estrogen synthesis in the breast is associated with MBD and one possible mechanism through which MBD may influence breast cancer. Eligible participants were 40+ years, had a screening mammogram with visible MBD and no prior cancer or current endocrine therapy. Mammograms were used to identify dense and non-dense regions and ultrasound-guided core biopsies were performed to obtain tissue from these regions. Immunostaining for aromatase employed the streptavidin–biotin amplification method and #677 mouse monoclonal antibody. Aromatase IR was scored in terms of extent and intensity of staining for each cell type (stroma, epithelium, adipocytes) on histologic sections. A modified histological H-score provided quantitation of aromatase IR in each cell type and overall. Repeated measure analyses evaluated average differences (βH) in H-score in dense versus non-dense tissue within and across cell types. Forty-nine women with mean age 50 years (range: 40–82), participated. Aromatase IR was increased in dense (vs. non-dense) tissue in both the stroma (βH = 0.58) and epithelium (βH = 0.12) (P < 0.01). Adipocytes from non-dense tissue, however, had a greater IR compared to those from dense tissue (βH = −0.24, P < 0.01). An overall H-score which integrated results from all cell types demonstrated that aromatase IR was twice as great for dense (mean H-score = 0.90, SD = 0.53) versus non-dense (mean H-score = 0.45, SD = 0.39) breast tissue (βH = 0.45; P < 0.001). Overall, aromatase IR was greater for mammographically dense versus non-dense tissue and may partly explain how MBD influences breast cancer.


Aromatase Breast density Dense area 



We thank the participants in this study, who provided samples for investigations of the determinants of breast density. This study was financially supported by the Mayo Clinic Breast SPORE, NIH CA116201; NIH K12 RR24151 for the KL2 Clinical and Translational Science Award-Mentored Career Development Program; and Friends for an Earlier Breast Cancer Test.

Supplementary material

10549_2010_944_MOESM1_ESM.doc (116 kb)
Supplementary material 1 (DOC 116 kb)


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Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  • Celine M. Vachon
    • 1
    Email author
  • Hironobu Sasano
    • 2
  • Karthik Ghosh
    • 1
  • Kathleen R. Brandt
    • 1
  • David A. Watson
    • 1
  • Carol Reynolds
    • 1
  • Wilma L. Lingle
    • 1
  • Paul E. Goss
    • 3
  • Rong Li
    • 5
  • Sarah E. Aiyar
    • 4
  • Christopher G. Scott
    • 1
  • V. Shane Pankratz
    • 1
  • Richard J. Santen
    • 4
  • James N. Ingle
    • 1
  1. 1.Mayo ClinicRochesterUSA
  2. 2.Tohoku University School of MedicineSendaiJapan
  3. 3.Massachusetts General HospitalBostonUSA
  4. 4.University of Virginia Health SystemCharlottesvilleUSA
  5. 5.University of Texas Health Science Center at San AntonioSan AntonioUSA

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