Erschienen in:
01.12.1999 | Commentary
Endogenous hormones and the aetiology of breast cancer
verfasst von:
Timothy J Key, Pia K Verkasalo
Erschienen in:
Breast Cancer Research
|
Ausgabe 1/1999
Einloggen, um Zugang zu erhalten
Excerpt
After several decades of epidemiological and laboratory research, how well do we understand the role of endogenous hormones in the aetiology of breast cancer? Early studies showed that risk varies with several hormonal events: risk is increased by early menarche and late menopause, and decreased by giving birth at a young age and by high parity. The protective effect of pregnancy is probably due to hormonally induced differentiation of breast epithelial cells, causing a reduction in the number of susceptible cells. The effects of age at menarche and menopause indicate that the duration of exposure to cyclic ovarian function is an important determinant of breast cancer risk, but it has proved difficult to establish whether oestradiol and/or progesterone is responsible, or to show whether variations in hormone levels between women have any important effect on risk. …