Expression of prolactin receptor mRNA in oestrogen receptor positive breast cancers pre- and post-tamoxifen therapy

Eur J Surg Oncol. 2004 Jun;30(5):515-9. doi: 10.1016/j.ejso.2003.03.001.


Aim: Previous in vitro studies have shown that tamoxifen down-regulates prolactin receptors in breast cancer cells. The aim of this study was to determine whether similar changes might provide the basis for a predictive test in patients.

Methods: Biopsy specimens were obtained from 28 post-menopausal women immediately before initiation of treatment with tamoxifen (20 mg daily) and after treatment for 7 days. Prolactin receptor mRNA, determined by reverse-transcription polymerase chain reaction, was then expressed relative to 18S ribosomal RNA.

Results: There was good evidence for a decline in receptor expression in response to treatment with tamoxifen in the whole group (p = 0.036) but with a particularly marked decrease (>60%) in a sub-group of 11 patients. No clear correlation with tumour type or grade, or with several other markers (progesterone receptor, c-erb B-2, pS2, or Bcl-2) was apparent.

Conclusion: Tamoxifen reduces expression of mRNA encoding the prolactin receptor in a sub-group of breast tumours and might provide the basis for a predictive test for tamoxifen therapy.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / biosynthesis
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Female
  • Humans
  • Immunohistochemistry
  • Middle Aged
  • Neoplasm Staging
  • Postmenopause / drug effects
  • Postmenopause / metabolism
  • RNA, Messenger / metabolism
  • RNA, Neoplasm / metabolism*
  • Receptors, Estrogen / metabolism*
  • Receptors, Progesterone / metabolism
  • Receptors, Prolactin / genetics*
  • Selective Estrogen Receptor Modulators / therapeutic use*
  • Tamoxifen / therapeutic use*
  • Women's Health


  • Biomarkers, Tumor
  • RNA, Messenger
  • RNA, Neoplasm
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Receptors, Prolactin
  • Selective Estrogen Receptor Modulators
  • Tamoxifen