The role of steroid hormones in breast cancer stem cells

    1. Robert B Clarke1
    1. 1Breast Biology Group, Breast Cancer Now Research Unit, Institute of Cancer Sciences, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
      2Department of Medical Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, UK
    1. Correspondence should be addressed to B M Simões; Email: Bruno.Simoes{at}


    Breast cancer stem cells (BCSCs) are potent tumor-initiating cells in breast cancer, the most common cancer among women. BCSCs have been suggested to play a key role in tumor initiation which can lead to disease progression and formation of metastases. Moreover, BCSCs are thought to be the unit of selection for therapy-resistant clones since they survive conventional treatments, such as chemotherapy, irradiation, and hormonal therapy. The importance of the role of hormones for both normal mammary gland and breast cancer development is well established, but it was not until recently that the effects of hormones on BCSCs have been investigated. This review will discuss recent studies highlighting how ovarian steroid hormones estrogen and progesterone, as well as therapies against them, can regulate BCSC activity.

    • Revision received 11 September 2015
    • Accepted 15 September 2015
    • Made available online as an Accepted Preprint 17 September 2015
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