title: Oestrogens, progestins and breast proliferation.
abstract: Aspects of the relation between endogenous and exogenous female sex steroids and the normal and malignant growth of the human breast are described. Starting points are the natural history of tumours, distinguishing between initiation, promotion and progression, and the risk factors for breast cancer as identified by epidemiology. The role of sex steroid hormones during the pubertal growth of the breast, the importance of the time between first growth and first pregnancy and the effects of pregnancy on the composition of the lobular structures in the human breast are discussed. The background of the suggested role of growth promoting effects of locally produced active oestrogens, especially in postmenopausal women, is given. From the evidence obtained from biochemical studies on the importance of the oestrogen production by the breast itself a mechanism is suggested to explain the possible lack of effects of exogenous oestrogens on the incidence of breast cancer.
authors.affiliation: Department of Endocrinology, Academisch Ziekenhuis Go2.625, Utrecht, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Thijssen
mesh_terms: D000818:Animals; D001940:Breast / Q000187:drug effects / Q000503:physiopathology; D001943:Breast Neoplasms / Q000139:chemically induced / Q000503:physiopathology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002979:Climacteric / Q000187:drug effects / Q000502:physiology; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D004967:Estrogens / Q000502:physiology*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011374:Progesterone / Q000502:physiology*; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000009:adverse effects; D012307:Risk Factors
chemical_list: D004967:Estrogens; D045167:Progesterone Congeners; D011374:Progesterone