Breast Cancer Research and Treatment

, Volume 48, Issue 1, pp 87–92 | Cite as

Predictive value of SRC-1 for tamoxifen response of recurrent breast cancer

  • Els M.J.J. Berns
  • Iris L. van Staveren
  • Jan G.M. Klijn
  • John A. Foekens


Tamoxifen causes an objective response in about one-third of metastatic breast cancer and in only half of the breast cancer patients with estrogen receptor (ER) positive tumors. Steroid-receptor coactivator-1 (SRC-1) appears to be a general coactivator for steroid receptors and rate limiting factor necessary for efficient ER transactivation. We aimed to evaluate whether SRC-1 expression is an additional factor for prediction of response to first-line tamoxifen therapy in patients who developed recurrent disease. Here for the first time, we report on SRC-1 expression using a semi-quantitative RT-PCR in 21 primary breast tumors, seven mammary tumor cell-lines, 12 fibroblast cultures, and six normal breast tissues. The highest levels of SRC-1 were observed in normal tissues, intermediate levels in tumor tissues, and the lowest levels in breast tumor cell-lines. There was no relationship between the levels of SRC-1 in these primary tumors and the proportion of tumor cells within the surgical samples, nor with ER status. The median SRC-1 level was, however, lower in tumors from patients that did not respond to tamoxifen. Our findings suggest that high levels of SRC-1 indicate a favorable response to tamoxifen of patients with recurrent breast cancer. Abbreviations: PgR, progesterone receptor; ER, estrogen receptor; GR, glucocorticoid receptor; TR, thyroid hormone receptor; RXR, retinoid X receptor; SRC-1, steroid-receptor coactivator-1; EGF, epidermal growth factor; TGF, transforming growth factor; IGF, insulin like growth factor; UPA, urokinase-type plasminogen activator

breast cancer SRC-1 RT-PCR response tamoxifen 


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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Els M.J.J. Berns
    • 1
  • Iris L. van Staveren
    • 1
  • Jan G.M. Klijn
    • 1
  • John A. Foekens
    • 1
  1. 1.Division of Endocrine Oncology (Department of Medical Oncology)Rotterdam Cancer Institute (Daniel den Hoed Kliniek)/University Hospital RotterdamRotterdamThe Netherlands

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