Early life events and conditions and breast cancer risk: From epidemiology to etiology

Authors

  • Dimitrios Trichopoulos,

    Corresponding author
    1. Department of Epidemiology, Harvard School of Public Health, Boston, MA
    • Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
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    • Fax: +1-617-566-7805

  • Hans-Olov Adami,

    1. Department of Epidemiology, Harvard School of Public Health, Boston, MA
    2. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
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  • Anders Ekbom,

    1. Department of Medicine, Unit of Clinical Epidemiology, Karolinska Institutet/Karolinska University Hospital, Stockholm, Sweden
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  • Chung-Cheng Hsieh,

    1. Department of Epidemiology, Harvard School of Public Health, Boston, MA
    2. Department of Cancer Biology and Cancer Center, University of Massachusetts Medical School, Worcester, MA
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  • Pagona Lagiou

    1. Department of Epidemiology, Harvard School of Public Health, Boston, MA
    2. Department of Hygiene and Epidemiology, School of Medicine, University of Athens, Greece
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  • Based on the Third Richard Doll lecture given at the International Agency for Research on Cancer by DT on May 9, 2007 and relying on the collective work of all authors.

Abstract

Risk factors for breast cancer—documented by intensive epidemiological investigations and viewed in the context of general principles of carcinogenesis—can be integrated to an etiologic model comprising 3 principal components: the likelihood of breast cancer occurrence depends on the number of mammary tissue-specific stem cells, which is determined in early life; all growth-enhancing mammotropic hormones affect the rate of expansion of initiated clones; and while a pregnancy stimulates the replication of already initiated cells, it conveys long-term protection through differentiation of mammary tissue-specific stem cells. This perspective accommodates much of what is known about the epidemiology and natural history of breast cancer and highlights the role of early life in the origin of this cancer. © 2007 Wiley-Liss, Inc.

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