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An Ex vivo Model to Study Hormone Action in the Human Breast
12:31

An Ex vivo Model to Study Hormone Action in the Human Breast

Published on: January 8, 2015

Extranuclear expression of hormone receptors in primary breast cancer

R Kim1, M Kaneko, K Arihiro

  • 1International Radiation Information Center, Department of Pathology, Hiroshima Asa City Hospital and Hiroshima University Hospital, Japan. rkim@hiroshima-u.ac.jp

Annals of Oncology : Official Journal of the European Society for Medical Oncology
|June 9, 2006
PubMed
Abstract

Insights

Extranuclear progesterone receptor (PR) is more common than estrogen receptor (ER) in breast cancer, suggesting PR

Area of Science:

  • Oncology
  • Endocrinology
  • Molecular Biology

Background:

  • Hormone receptor (HR)-positive breast cancer growth involves estrogen receptor (ER) signaling.
  • ER signaling has both genomic and nongenomic actions, interacting with growth factors.
  • This interaction can lead to resistance to tamoxifen treatment.

Purpose of the Study:

  • To investigate the cross-talk between extranuclear ER and progesterone receptor (PR) expression.
  • To examine the relationship with growth factor signaling pathways in primary breast cancer.

Main Methods:

  • Examined extranuclear ER and PR expression in 219 primary breast cancers using immunohistochemical staining.
  • Assessed co-expression of pAkt and aromatase in specimens with extranuclear HR expression.
  • Scored staining intensity and distribution for quantitative analysis.

Main Results:

  • Extranuclear ER or PR expression found in 9.5% of cases (21/219).
  • HER-2, pAkt, and aromatase positivity observed in 66.6%, 61.9%, and 66.6% of these cases, respectively.
  • Elevated pAkt and aromatase were significantly associated with ER-positive/PR-negative cases (90.9% and 81.8%, respectively).

Conclusions:

  • Extranuclear PR expression is more frequent than ER in primary breast cancer.
  • Extranuclear HRs interact with Akt/HER-2 signaling pathways and aromatase activation.
  • Findings may explain improved outcomes with aromatase inhibitors over tamoxifen in ER-positive/PR-negative patients.

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