title: Do estrogens always increase breast cancer risk?
abstract: The etiology of breast cancer is closely linked to the female hormone estrogen, with high life-time exposure being suggested to increase breast cancer risk [Nature 303 (1983) 767]. However, there appears to be a disparity between studies attempting to establish an association between high estrogen levels and breast cancer risk. This disparity becomes smaller by taking into consideration a timing factor, and we propose that estrogens can increase, decrease, or have no effect on breast cancer risk, depending on the timing of estrogen exposure. We further propose that the timing of estrogenic exposures may play at least as important a role in affecting breast cancer risk as life-time exposure.
authors.affiliation: Lombardi Cancer Center and Department of Oncology, Georgetown University, Room W405, 3970 Reservoir Road NW, Washington, DC 20007, USA. clarkel@gunet.georgetown.edu
authors.forename: Leena
authors.initials: L
authors.lastname: Hilakivi-Clarke
authors.forename: Anna
authors.initials: A
authors.lastname: Cabanes
authors.forename: Susan
authors.initials: S
authors.lastname: Olivo
authors.forename: Leslie
authors.initials: L
authors.lastname: Kerr
authors.forename: Kerrie B
authors.initials: KB
authors.lastname: Bouker
authors.forename: Robert
authors.initials: R
authors.lastname: Clarke
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D004781:Environmental Exposure; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens / Q000502:physiology*; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000502:physiology; D012307:Risk Factors
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D011960:Receptors, Estrogen